FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
avcodec.h
Go to the documentation of this file.
1 /*
2  * copyright (c) 2001 Fabrice Bellard
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVCODEC_AVCODEC_H
22 #define AVCODEC_AVCODEC_H
23 
24 /**
25  * @file
26  * @ingroup libavc
27  * Libavcodec external API header
28  */
29 
30 #include <errno.h>
31 #include "libavutil/samplefmt.h"
32 #include "libavutil/attributes.h"
33 #include "libavutil/avutil.h"
34 #include "libavutil/buffer.h"
35 #include "libavutil/cpu.h"
37 #include "libavutil/dict.h"
38 #include "libavutil/frame.h"
39 #include "libavutil/hwcontext.h"
40 #include "libavutil/log.h"
41 #include "libavutil/pixfmt.h"
42 #include "libavutil/rational.h"
43 
44 #include "version.h"
45 
46 /**
47  * @defgroup libavc libavcodec
48  * Encoding/Decoding Library
49  *
50  * @{
51  *
52  * @defgroup lavc_decoding Decoding
53  * @{
54  * @}
55  *
56  * @defgroup lavc_encoding Encoding
57  * @{
58  * @}
59  *
60  * @defgroup lavc_codec Codecs
61  * @{
62  * @defgroup lavc_codec_native Native Codecs
63  * @{
64  * @}
65  * @defgroup lavc_codec_wrappers External library wrappers
66  * @{
67  * @}
68  * @defgroup lavc_codec_hwaccel Hardware Accelerators bridge
69  * @{
70  * @}
71  * @}
72  * @defgroup lavc_internal Internal
73  * @{
74  * @}
75  * @}
76  */
77 
78 /**
79  * @ingroup libavc
80  * @defgroup lavc_encdec send/receive encoding and decoding API overview
81  * @{
82  *
83  * The avcodec_send_packet()/avcodec_receive_frame()/avcodec_send_frame()/
84  * avcodec_receive_packet() functions provide an encode/decode API, which
85  * decouples input and output.
86  *
87  * The API is very similar for encoding/decoding and audio/video, and works as
88  * follows:
89  * - Set up and open the AVCodecContext as usual.
90  * - Send valid input:
91  * - For decoding, call avcodec_send_packet() to give the decoder raw
92  * compressed data in an AVPacket.
93  * - For encoding, call avcodec_send_frame() to give the encoder an AVFrame
94  * containing uncompressed audio or video.
95  * In both cases, it is recommended that AVPackets and AVFrames are
96  * refcounted, or libavcodec might have to copy the input data. (libavformat
97  * always returns refcounted AVPackets, and av_frame_get_buffer() allocates
98  * refcounted AVFrames.)
99  * - Receive output in a loop. Periodically call one of the avcodec_receive_*()
100  * functions and process their output:
101  * - For decoding, call avcodec_receive_frame(). On success, it will return
102  * an AVFrame containing uncompressed audio or video data.
103  * - For encoding, call avcodec_receive_packet(). On success, it will return
104  * an AVPacket with a compressed frame.
105  * Repeat this call until it returns AVERROR(EAGAIN) or an error. The
106  * AVERROR(EAGAIN) return value means that new input data is required to
107  * return new output. In this case, continue with sending input. For each
108  * input frame/packet, the codec will typically return 1 output frame/packet,
109  * but it can also be 0 or more than 1.
110  *
111  * At the beginning of decoding or encoding, the codec might accept multiple
112  * input frames/packets without returning a frame, until its internal buffers
113  * are filled. This situation is handled transparently if you follow the steps
114  * outlined above.
115  *
116  * In theory, sending input can result in EAGAIN - this should happen only if
117  * not all output was received. You can use this to structure alternative decode
118  * or encode loops other than the one suggested above. For example, you could
119  * try sending new input on each iteration, and try to receive output if that
120  * returns EAGAIN.
121  *
122  * End of stream situations. These require "flushing" (aka draining) the codec,
123  * as the codec might buffer multiple frames or packets internally for
124  * performance or out of necessity (consider B-frames).
125  * This is handled as follows:
126  * - Instead of valid input, send NULL to the avcodec_send_packet() (decoding)
127  * or avcodec_send_frame() (encoding) functions. This will enter draining
128  * mode.
129  * - Call avcodec_receive_frame() (decoding) or avcodec_receive_packet()
130  * (encoding) in a loop until AVERROR_EOF is returned. The functions will
131  * not return AVERROR(EAGAIN), unless you forgot to enter draining mode.
132  * - Before decoding can be resumed again, the codec has to be reset with
133  * avcodec_flush_buffers().
134  *
135  * Using the API as outlined above is highly recommended. But it is also
136  * possible to call functions outside of this rigid schema. For example, you can
137  * call avcodec_send_packet() repeatedly without calling
138  * avcodec_receive_frame(). In this case, avcodec_send_packet() will succeed
139  * until the codec's internal buffer has been filled up (which is typically of
140  * size 1 per output frame, after initial input), and then reject input with
141  * AVERROR(EAGAIN). Once it starts rejecting input, you have no choice but to
142  * read at least some output.
143  *
144  * Not all codecs will follow a rigid and predictable dataflow; the only
145  * guarantee is that an AVERROR(EAGAIN) return value on a send/receive call on
146  * one end implies that a receive/send call on the other end will succeed, or
147  * at least will not fail with AVERROR(EAGAIN). In general, no codec will
148  * permit unlimited buffering of input or output.
149  *
150  * This API replaces the following legacy functions:
151  * - avcodec_decode_video2() and avcodec_decode_audio4():
152  * Use avcodec_send_packet() to feed input to the decoder, then use
153  * avcodec_receive_frame() to receive decoded frames after each packet.
154  * Unlike with the old video decoding API, multiple frames might result from
155  * a packet. For audio, splitting the input packet into frames by partially
156  * decoding packets becomes transparent to the API user. You never need to
157  * feed an AVPacket to the API twice (unless it is rejected with AVERROR(EAGAIN) - then
158  * no data was read from the packet).
159  * Additionally, sending a flush/draining packet is required only once.
160  * - avcodec_encode_video2()/avcodec_encode_audio2():
161  * Use avcodec_send_frame() to feed input to the encoder, then use
162  * avcodec_receive_packet() to receive encoded packets.
163  * Providing user-allocated buffers for avcodec_receive_packet() is not
164  * possible.
165  * - The new API does not handle subtitles yet.
166  *
167  * Mixing new and old function calls on the same AVCodecContext is not allowed,
168  * and will result in undefined behavior.
169  *
170  * Some codecs might require using the new API; using the old API will return
171  * an error when calling it. All codecs support the new API.
172  *
173  * A codec is not allowed to return AVERROR(EAGAIN) for both sending and receiving. This
174  * would be an invalid state, which could put the codec user into an endless
175  * loop. The API has no concept of time either: it cannot happen that trying to
176  * do avcodec_send_packet() results in AVERROR(EAGAIN), but a repeated call 1 second
177  * later accepts the packet (with no other receive/flush API calls involved).
178  * The API is a strict state machine, and the passage of time is not supposed
179  * to influence it. Some timing-dependent behavior might still be deemed
180  * acceptable in certain cases. But it must never result in both send/receive
181  * returning EAGAIN at the same time at any point. It must also absolutely be
182  * avoided that the current state is "unstable" and can "flip-flop" between
183  * the send/receive APIs allowing progress. For example, it's not allowed that
184  * the codec randomly decides that it actually wants to consume a packet now
185  * instead of returning a frame, after it just returned AVERROR(EAGAIN) on an
186  * avcodec_send_packet() call.
187  * @}
188  */
189 
190 /**
191  * @defgroup lavc_core Core functions/structures.
192  * @ingroup libavc
193  *
194  * Basic definitions, functions for querying libavcodec capabilities,
195  * allocating core structures, etc.
196  * @{
197  */
198 
199 
200 /**
201  * Identify the syntax and semantics of the bitstream.
202  * The principle is roughly:
203  * Two decoders with the same ID can decode the same streams.
204  * Two encoders with the same ID can encode compatible streams.
205  * There may be slight deviations from the principle due to implementation
206  * details.
207  *
208  * If you add a codec ID to this list, add it so that
209  * 1. no value of an existing codec ID changes (that would break ABI),
210  * 2. it is as close as possible to similar codecs
211  *
212  * After adding new codec IDs, do not forget to add an entry to the codec
213  * descriptor list and bump libavcodec minor version.
214  */
215 enum AVCodecID {
217 
218  /* video codecs */
220  AV_CODEC_ID_MPEG2VIDEO, ///< preferred ID for MPEG-1/2 video decoding
355 #define AV_CODEC_ID_IFF_BYTERUN1 AV_CODEC_ID_IFF_ILBM
393 #define AV_CODEC_ID_H265 AV_CODEC_ID_HEVC
412 
449 
450  /* various PCM "codecs" */
451  AV_CODEC_ID_FIRST_AUDIO = 0x10000, ///< A dummy id pointing at the start of audio codecs
483 
488 
489  /* various ADPCM codecs */
521 
532 
533  /* AMR */
536 
537  /* RealAudio codecs*/
540 
541  /* various DPCM codecs */
546 
549 
550  /* audio codecs */
551  AV_CODEC_ID_MP2 = 0x15000,
552  AV_CODEC_ID_MP3, ///< preferred ID for decoding MPEG audio layer 1, 2 or 3
569  AV_CODEC_ID_GSM, ///< as in Berlin toast format
581  AV_CODEC_ID_GSM_MS, /* as found in WAV */
618 
637 
638  /* subtitle codecs */
639  AV_CODEC_ID_FIRST_SUBTITLE = 0x17000, ///< A dummy ID pointing at the start of subtitle codecs.
642  AV_CODEC_ID_TEXT, ///< raw UTF-8 text
649 
665 
666  /* other specific kind of codecs (generally used for attachments) */
667  AV_CODEC_ID_FIRST_UNKNOWN = 0x18000, ///< A dummy ID pointing at the start of various fake codecs.
668  AV_CODEC_ID_TTF = 0x18000,
669 
670  AV_CODEC_ID_SCTE_35, ///< Contain timestamp estimated through PCR of program stream.
679 
680 
681  AV_CODEC_ID_PROBE = 0x19000, ///< codec_id is not known (like AV_CODEC_ID_NONE) but lavf should attempt to identify it
682 
683  AV_CODEC_ID_MPEG2TS = 0x20000, /**< _FAKE_ codec to indicate a raw MPEG-2 TS
684  * stream (only used by libavformat) */
685  AV_CODEC_ID_MPEG4SYSTEMS = 0x20001, /**< _FAKE_ codec to indicate a MPEG-4 Systems
686  * stream (only used by libavformat) */
687  AV_CODEC_ID_FFMETADATA = 0x21000, ///< Dummy codec for streams containing only metadata information.
688  AV_CODEC_ID_WRAPPED_AVFRAME = 0x21001, ///< Passthrough codec, AVFrames wrapped in AVPacket
689 };
690 
691 /**
692  * This struct describes the properties of a single codec described by an
693  * AVCodecID.
694  * @see avcodec_descriptor_get()
695  */
696 typedef struct AVCodecDescriptor {
697  enum AVCodecID id;
699  /**
700  * Name of the codec described by this descriptor. It is non-empty and
701  * unique for each codec descriptor. It should contain alphanumeric
702  * characters and '_' only.
703  */
704  const char *name;
705  /**
706  * A more descriptive name for this codec. May be NULL.
707  */
708  const char *long_name;
709  /**
710  * Codec properties, a combination of AV_CODEC_PROP_* flags.
711  */
712  int props;
713  /**
714  * MIME type(s) associated with the codec.
715  * May be NULL; if not, a NULL-terminated array of MIME types.
716  * The first item is always non-NULL and is the preferred MIME type.
717  */
718  const char *const *mime_types;
719  /**
720  * If non-NULL, an array of profiles recognized for this codec.
721  * Terminated with FF_PROFILE_UNKNOWN.
722  */
723  const struct AVProfile *profiles;
725 
726 /**
727  * Codec uses only intra compression.
728  * Video and audio codecs only.
729  */
730 #define AV_CODEC_PROP_INTRA_ONLY (1 << 0)
731 /**
732  * Codec supports lossy compression. Audio and video codecs only.
733  * @note a codec may support both lossy and lossless
734  * compression modes
735  */
736 #define AV_CODEC_PROP_LOSSY (1 << 1)
737 /**
738  * Codec supports lossless compression. Audio and video codecs only.
739  */
740 #define AV_CODEC_PROP_LOSSLESS (1 << 2)
741 /**
742  * Codec supports frame reordering. That is, the coded order (the order in which
743  * the encoded packets are output by the encoders / stored / input to the
744  * decoders) may be different from the presentation order of the corresponding
745  * frames.
746  *
747  * For codecs that do not have this property set, PTS and DTS should always be
748  * equal.
749  */
750 #define AV_CODEC_PROP_REORDER (1 << 3)
751 /**
752  * Subtitle codec is bitmap based
753  * Decoded AVSubtitle data can be read from the AVSubtitleRect->pict field.
754  */
755 #define AV_CODEC_PROP_BITMAP_SUB (1 << 16)
756 /**
757  * Subtitle codec is text based.
758  * Decoded AVSubtitle data can be read from the AVSubtitleRect->ass field.
759  */
760 #define AV_CODEC_PROP_TEXT_SUB (1 << 17)
761 
762 /**
763  * @ingroup lavc_decoding
764  * Required number of additionally allocated bytes at the end of the input bitstream for decoding.
765  * This is mainly needed because some optimized bitstream readers read
766  * 32 or 64 bit at once and could read over the end.<br>
767  * Note: If the first 23 bits of the additional bytes are not 0, then damaged
768  * MPEG bitstreams could cause overread and segfault.
769  */
770 #define AV_INPUT_BUFFER_PADDING_SIZE 32
771 
772 /**
773  * @ingroup lavc_encoding
774  * minimum encoding buffer size
775  * Used to avoid some checks during header writing.
776  */
777 #define AV_INPUT_BUFFER_MIN_SIZE 16384
778 
779 /**
780  * @ingroup lavc_decoding
781  */
783  /* We leave some space between them for extensions (drop some
784  * keyframes for intra-only or drop just some bidir frames). */
785  AVDISCARD_NONE =-16, ///< discard nothing
786  AVDISCARD_DEFAULT = 0, ///< discard useless packets like 0 size packets in avi
787  AVDISCARD_NONREF = 8, ///< discard all non reference
788  AVDISCARD_BIDIR = 16, ///< discard all bidirectional frames
789  AVDISCARD_NONINTRA= 24, ///< discard all non intra frames
790  AVDISCARD_NONKEY = 32, ///< discard all frames except keyframes
791  AVDISCARD_ALL = 48, ///< discard all
792 };
793 
804  AV_AUDIO_SERVICE_TYPE_NB , ///< Not part of ABI
805 };
806 
807 /**
808  * @ingroup lavc_encoding
809  */
810 typedef struct RcOverride{
813  int qscale; // If this is 0 then quality_factor will be used instead.
815 } RcOverride;
816 
817 /* encoding support
818  These flags can be passed in AVCodecContext.flags before initialization.
819  Note: Not everything is supported yet.
820 */
821 
822 /**
823  * Allow decoders to produce frames with data planes that are not aligned
824  * to CPU requirements (e.g. due to cropping).
825  */
826 #define AV_CODEC_FLAG_UNALIGNED (1 << 0)
827 /**
828  * Use fixed qscale.
829  */
830 #define AV_CODEC_FLAG_QSCALE (1 << 1)
831 /**
832  * 4 MV per MB allowed / advanced prediction for H.263.
833  */
834 #define AV_CODEC_FLAG_4MV (1 << 2)
835 /**
836  * Output even those frames that might be corrupted.
837  */
838 #define AV_CODEC_FLAG_OUTPUT_CORRUPT (1 << 3)
839 /**
840  * Use qpel MC.
841  */
842 #define AV_CODEC_FLAG_QPEL (1 << 4)
843 /**
844  * Use internal 2pass ratecontrol in first pass mode.
845  */
846 #define AV_CODEC_FLAG_PASS1 (1 << 9)
847 /**
848  * Use internal 2pass ratecontrol in second pass mode.
849  */
850 #define AV_CODEC_FLAG_PASS2 (1 << 10)
851 /**
852  * loop filter.
853  */
854 #define AV_CODEC_FLAG_LOOP_FILTER (1 << 11)
855 /**
856  * Only decode/encode grayscale.
857  */
858 #define AV_CODEC_FLAG_GRAY (1 << 13)
859 /**
860  * error[?] variables will be set during encoding.
861  */
862 #define AV_CODEC_FLAG_PSNR (1 << 15)
863 /**
864  * Input bitstream might be truncated at a random location
865  * instead of only at frame boundaries.
866  */
867 #define AV_CODEC_FLAG_TRUNCATED (1 << 16)
868 /**
869  * Use interlaced DCT.
870  */
871 #define AV_CODEC_FLAG_INTERLACED_DCT (1 << 18)
872 /**
873  * Force low delay.
874  */
875 #define AV_CODEC_FLAG_LOW_DELAY (1 << 19)
876 /**
877  * Place global headers in extradata instead of every keyframe.
878  */
879 #define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)
880 /**
881  * Use only bitexact stuff (except (I)DCT).
882  */
883 #define AV_CODEC_FLAG_BITEXACT (1 << 23)
884 /* Fx : Flag for H.263+ extra options */
885 /**
886  * H.263 advanced intra coding / MPEG-4 AC prediction
887  */
888 #define AV_CODEC_FLAG_AC_PRED (1 << 24)
889 /**
890  * interlaced motion estimation
891  */
892 #define AV_CODEC_FLAG_INTERLACED_ME (1 << 29)
893 #define AV_CODEC_FLAG_CLOSED_GOP (1U << 31)
894 
895 /**
896  * Allow non spec compliant speedup tricks.
897  */
898 #define AV_CODEC_FLAG2_FAST (1 << 0)
899 /**
900  * Skip bitstream encoding.
901  */
902 #define AV_CODEC_FLAG2_NO_OUTPUT (1 << 2)
903 /**
904  * Place global headers at every keyframe instead of in extradata.
905  */
906 #define AV_CODEC_FLAG2_LOCAL_HEADER (1 << 3)
907 
908 /**
909  * timecode is in drop frame format. DEPRECATED!!!!
910  */
911 #define AV_CODEC_FLAG2_DROP_FRAME_TIMECODE (1 << 13)
912 
913 /**
914  * Input bitstream might be truncated at a packet boundaries
915  * instead of only at frame boundaries.
916  */
917 #define AV_CODEC_FLAG2_CHUNKS (1 << 15)
918 /**
919  * Discard cropping information from SPS.
920  */
921 #define AV_CODEC_FLAG2_IGNORE_CROP (1 << 16)
922 
923 /**
924  * Show all frames before the first keyframe
925  */
926 #define AV_CODEC_FLAG2_SHOW_ALL (1 << 22)
927 /**
928  * Export motion vectors through frame side data
929  */
930 #define AV_CODEC_FLAG2_EXPORT_MVS (1 << 28)
931 /**
932  * Do not skip samples and export skip information as frame side data
933  */
934 #define AV_CODEC_FLAG2_SKIP_MANUAL (1 << 29)
935 /**
936  * Do not reset ASS ReadOrder field on flush (subtitles decoding)
937  */
938 #define AV_CODEC_FLAG2_RO_FLUSH_NOOP (1 << 30)
939 
940 /* Unsupported options :
941  * Syntax Arithmetic coding (SAC)
942  * Reference Picture Selection
943  * Independent Segment Decoding */
944 /* /Fx */
945 /* codec capabilities */
946 
947 /**
948  * Decoder can use draw_horiz_band callback.
949  */
950 #define AV_CODEC_CAP_DRAW_HORIZ_BAND (1 << 0)
951 /**
952  * Codec uses get_buffer() for allocating buffers and supports custom allocators.
953  * If not set, it might not use get_buffer() at all or use operations that
954  * assume the buffer was allocated by avcodec_default_get_buffer.
955  */
956 #define AV_CODEC_CAP_DR1 (1 << 1)
957 #define AV_CODEC_CAP_TRUNCATED (1 << 3)
958 /**
959  * Encoder or decoder requires flushing with NULL input at the end in order to
960  * give the complete and correct output.
961  *
962  * NOTE: If this flag is not set, the codec is guaranteed to never be fed with
963  * with NULL data. The user can still send NULL data to the public encode
964  * or decode function, but libavcodec will not pass it along to the codec
965  * unless this flag is set.
966  *
967  * Decoders:
968  * The decoder has a non-zero delay and needs to be fed with avpkt->data=NULL,
969  * avpkt->size=0 at the end to get the delayed data until the decoder no longer
970  * returns frames.
971  *
972  * Encoders:
973  * The encoder needs to be fed with NULL data at the end of encoding until the
974  * encoder no longer returns data.
975  *
976  * NOTE: For encoders implementing the AVCodec.encode2() function, setting this
977  * flag also means that the encoder must set the pts and duration for
978  * each output packet. If this flag is not set, the pts and duration will
979  * be determined by libavcodec from the input frame.
980  */
981 #define AV_CODEC_CAP_DELAY (1 << 5)
982 /**
983  * Codec can be fed a final frame with a smaller size.
984  * This can be used to prevent truncation of the last audio samples.
985  */
986 #define AV_CODEC_CAP_SMALL_LAST_FRAME (1 << 6)
987 
988 /**
989  * Codec can output multiple frames per AVPacket
990  * Normally demuxers return one frame at a time, demuxers which do not do
991  * are connected to a parser to split what they return into proper frames.
992  * This flag is reserved to the very rare category of codecs which have a
993  * bitstream that cannot be split into frames without timeconsuming
994  * operations like full decoding. Demuxers carrying such bitstreams thus
995  * may return multiple frames in a packet. This has many disadvantages like
996  * prohibiting stream copy in many cases thus it should only be considered
997  * as a last resort.
998  */
999 #define AV_CODEC_CAP_SUBFRAMES (1 << 8)
1000 /**
1001  * Codec is experimental and is thus avoided in favor of non experimental
1002  * encoders
1003  */
1004 #define AV_CODEC_CAP_EXPERIMENTAL (1 << 9)
1005 /**
1006  * Codec should fill in channel configuration and samplerate instead of container
1007  */
1008 #define AV_CODEC_CAP_CHANNEL_CONF (1 << 10)
1009 /**
1010  * Codec supports frame-level multithreading.
1011  */
1012 #define AV_CODEC_CAP_FRAME_THREADS (1 << 12)
1013 /**
1014  * Codec supports slice-based (or partition-based) multithreading.
1015  */
1016 #define AV_CODEC_CAP_SLICE_THREADS (1 << 13)
1017 /**
1018  * Codec supports changed parameters at any point.
1019  */
1020 #define AV_CODEC_CAP_PARAM_CHANGE (1 << 14)
1021 /**
1022  * Codec supports avctx->thread_count == 0 (auto).
1023  */
1024 #define AV_CODEC_CAP_AUTO_THREADS (1 << 15)
1025 /**
1026  * Audio encoder supports receiving a different number of samples in each call.
1027  */
1028 #define AV_CODEC_CAP_VARIABLE_FRAME_SIZE (1 << 16)
1029 /**
1030  * Decoder is not a preferred choice for probing.
1031  * This indicates that the decoder is not a good choice for probing.
1032  * It could for example be an expensive to spin up hardware decoder,
1033  * or it could simply not provide a lot of useful information about
1034  * the stream.
1035  * A decoder marked with this flag should only be used as last resort
1036  * choice for probing.
1037  */
1038 #define AV_CODEC_CAP_AVOID_PROBING (1 << 17)
1039 /**
1040  * Codec is intra only.
1041  */
1042 #define AV_CODEC_CAP_INTRA_ONLY 0x40000000
1043 /**
1044  * Codec is lossless.
1045  */
1046 #define AV_CODEC_CAP_LOSSLESS 0x80000000
1047 
1048 /**
1049  * Pan Scan area.
1050  * This specifies the area which should be displayed.
1051  * Note there may be multiple such areas for one frame.
1052  */
1053 typedef struct AVPanScan {
1054  /**
1055  * id
1056  * - encoding: Set by user.
1057  * - decoding: Set by libavcodec.
1058  */
1059  int id;
1060 
1061  /**
1062  * width and height in 1/16 pel
1063  * - encoding: Set by user.
1064  * - decoding: Set by libavcodec.
1065  */
1066  int width;
1067  int height;
1068 
1069  /**
1070  * position of the top left corner in 1/16 pel for up to 3 fields/frames
1071  * - encoding: Set by user.
1072  * - decoding: Set by libavcodec.
1073  */
1074  int16_t position[3][2];
1075 } AVPanScan;
1076 
1077 /**
1078  * This structure describes the bitrate properties of an encoded bitstream. It
1079  * roughly corresponds to a subset the VBV parameters for MPEG-2 or HRD
1080  * parameters for H.264/HEVC.
1081  */
1082 typedef struct AVCPBProperties {
1083  /**
1084  * Maximum bitrate of the stream, in bits per second.
1085  * Zero if unknown or unspecified.
1086  */
1088  /**
1089  * Minimum bitrate of the stream, in bits per second.
1090  * Zero if unknown or unspecified.
1091  */
1093  /**
1094  * Average bitrate of the stream, in bits per second.
1095  * Zero if unknown or unspecified.
1096  */
1098 
1099  /**
1100  * The size of the buffer to which the ratecontrol is applied, in bits.
1101  * Zero if unknown or unspecified.
1102  */
1104 
1105  /**
1106  * The delay between the time the packet this structure is associated with
1107  * is received and the time when it should be decoded, in periods of a 27MHz
1108  * clock.
1109  *
1110  * UINT64_MAX when unknown or unspecified.
1111  */
1112  uint64_t vbv_delay;
1113 } AVCPBProperties;
1114 
1115 /**
1116  * The decoder will keep a reference to the frame and may reuse it later.
1117  */
1118 #define AV_GET_BUFFER_FLAG_REF (1 << 0)
1119 
1120 /**
1121  * @defgroup lavc_packet AVPacket
1122  *
1123  * Types and functions for working with AVPacket.
1124  * @{
1125  */
1127  /**
1128  * An AV_PKT_DATA_PALETTE side data packet contains exactly AVPALETTE_SIZE
1129  * bytes worth of palette. This side data signals that a new palette is
1130  * present.
1131  */
1133 
1134  /**
1135  * The AV_PKT_DATA_NEW_EXTRADATA is used to notify the codec or the format
1136  * that the extradata buffer was changed and the receiving side should
1137  * act upon it appropriately. The new extradata is embedded in the side
1138  * data buffer and should be immediately used for processing the current
1139  * frame or packet.
1140  */
1142 
1143  /**
1144  * An AV_PKT_DATA_PARAM_CHANGE side data packet is laid out as follows:
1145  * @code
1146  * u32le param_flags
1147  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT)
1148  * s32le channel_count
1149  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT)
1150  * u64le channel_layout
1151  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE)
1152  * s32le sample_rate
1153  * if (param_flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS)
1154  * s32le width
1155  * s32le height
1156  * @endcode
1157  */
1159 
1160  /**
1161  * An AV_PKT_DATA_H263_MB_INFO side data packet contains a number of
1162  * structures with info about macroblocks relevant to splitting the
1163  * packet into smaller packets on macroblock edges (e.g. as for RFC 2190).
1164  * That is, it does not necessarily contain info about all macroblocks,
1165  * as long as the distance between macroblocks in the info is smaller
1166  * than the target payload size.
1167  * Each MB info structure is 12 bytes, and is laid out as follows:
1168  * @code
1169  * u32le bit offset from the start of the packet
1170  * u8 current quantizer at the start of the macroblock
1171  * u8 GOB number
1172  * u16le macroblock address within the GOB
1173  * u8 horizontal MV predictor
1174  * u8 vertical MV predictor
1175  * u8 horizontal MV predictor for block number 3
1176  * u8 vertical MV predictor for block number 3
1177  * @endcode
1178  */
1180 
1181  /**
1182  * This side data should be associated with an audio stream and contains
1183  * ReplayGain information in form of the AVReplayGain struct.
1184  */
1186 
1187  /**
1188  * This side data contains a 3x3 transformation matrix describing an affine
1189  * transformation that needs to be applied to the decoded video frames for
1190  * correct presentation.
1191  *
1192  * See libavutil/display.h for a detailed description of the data.
1193  */
1195 
1196  /**
1197  * This side data should be associated with a video stream and contains
1198  * Stereoscopic 3D information in form of the AVStereo3D struct.
1199  */
1201 
1202  /**
1203  * This side data should be associated with an audio stream and corresponds
1204  * to enum AVAudioServiceType.
1205  */
1207 
1208  /**
1209  * This side data contains quality related information from the encoder.
1210  * @code
1211  * u32le quality factor of the compressed frame. Allowed range is between 1 (good) and FF_LAMBDA_MAX (bad).
1212  * u8 picture type
1213  * u8 error count
1214  * u16 reserved
1215  * u64le[error count] sum of squared differences between encoder in and output
1216  * @endcode
1217  */
1219 
1220  /**
1221  * This side data contains an integer value representing the stream index
1222  * of a "fallback" track. A fallback track indicates an alternate
1223  * track to use when the current track can not be decoded for some reason.
1224  * e.g. no decoder available for codec.
1225  */
1227 
1228  /**
1229  * This side data corresponds to the AVCPBProperties struct.
1230  */
1232 
1233  /**
1234  * Recommmends skipping the specified number of samples
1235  * @code
1236  * u32le number of samples to skip from start of this packet
1237  * u32le number of samples to skip from end of this packet
1238  * u8 reason for start skip
1239  * u8 reason for end skip (0=padding silence, 1=convergence)
1240  * @endcode
1241  */
1243 
1244  /**
1245  * An AV_PKT_DATA_JP_DUALMONO side data packet indicates that
1246  * the packet may contain "dual mono" audio specific to Japanese DTV
1247  * and if it is true, recommends only the selected channel to be used.
1248  * @code
1249  * u8 selected channels (0=mail/left, 1=sub/right, 2=both)
1250  * @endcode
1251  */
1253 
1254  /**
1255  * A list of zero terminated key/value strings. There is no end marker for
1256  * the list, so it is required to rely on the side data size to stop.
1257  */
1259 
1260  /**
1261  * Subtitle event position
1262  * @code
1263  * u32le x1
1264  * u32le y1
1265  * u32le x2
1266  * u32le y2
1267  * @endcode
1268  */
1270 
1271  /**
1272  * Data found in BlockAdditional element of matroska container. There is
1273  * no end marker for the data, so it is required to rely on the side data
1274  * size to recognize the end. 8 byte id (as found in BlockAddId) followed
1275  * by data.
1276  */
1278 
1279  /**
1280  * The optional first identifier line of a WebVTT cue.
1281  */
1283 
1284  /**
1285  * The optional settings (rendering instructions) that immediately
1286  * follow the timestamp specifier of a WebVTT cue.
1287  */
1289 
1290  /**
1291  * A list of zero terminated key/value strings. There is no end marker for
1292  * the list, so it is required to rely on the side data size to stop. This
1293  * side data includes updated metadata which appeared in the stream.
1294  */
1296 
1297  /**
1298  * MPEGTS stream ID, this is required to pass the stream ID
1299  * information from the demuxer to the corresponding muxer.
1300  */
1302 
1303  /**
1304  * Mastering display metadata (based on SMPTE-2086:2014). This metadata
1305  * should be associated with a video stream and contains data in the form
1306  * of the AVMasteringDisplayMetadata struct.
1307  */
1309 
1310  /**
1311  * This side data should be associated with a video stream and corresponds
1312  * to the AVSphericalMapping structure.
1313  */
1315 
1316  /**
1317  * Content light level (based on CTA-861.3). This metadata should be
1318  * associated with a video stream and contains data in the form of the
1319  * AVContentLightMetadata struct.
1320  */
1322 
1323  /**
1324  * ATSC A53 Part 4 Closed Captions. This metadata should be associated with
1325  * a video stream. A53 CC bitstream is stored as uint8_t in AVPacketSideData.data.
1326  * The number of bytes of CC data is AVPacketSideData.size.
1327  */
1329 
1330  /**
1331  * The number of side data types.
1332  * This is not part of the public API/ABI in the sense that it may
1333  * change when new side data types are added.
1334  * This must stay the last enum value.
1335  * If its value becomes huge, some code using it
1336  * needs to be updated as it assumes it to be smaller than other limits.
1337  */
1339 };
1340 
1341 #define AV_PKT_DATA_QUALITY_FACTOR AV_PKT_DATA_QUALITY_STATS //DEPRECATED
1342 
1343 typedef struct AVPacketSideData {
1345  int size;
1348 
1349 /**
1350  * This structure stores compressed data. It is typically exported by demuxers
1351  * and then passed as input to decoders, or received as output from encoders and
1352  * then passed to muxers.
1353  *
1354  * For video, it should typically contain one compressed frame. For audio it may
1355  * contain several compressed frames. Encoders are allowed to output empty
1356  * packets, with no compressed data, containing only side data
1357  * (e.g. to update some stream parameters at the end of encoding).
1358  *
1359  * AVPacket is one of the few structs in FFmpeg, whose size is a part of public
1360  * ABI. Thus it may be allocated on stack and no new fields can be added to it
1361  * without libavcodec and libavformat major bump.
1362  *
1363  * The semantics of data ownership depends on the buf field.
1364  * If it is set, the packet data is dynamically allocated and is
1365  * valid indefinitely until a call to av_packet_unref() reduces the
1366  * reference count to 0.
1367  *
1368  * If the buf field is not set av_packet_ref() would make a copy instead
1369  * of increasing the reference count.
1370  *
1371  * The side data is always allocated with av_malloc(), copied by
1372  * av_packet_ref() and freed by av_packet_unref().
1373  *
1374  * @see av_packet_ref
1375  * @see av_packet_unref
1376  */
1377 typedef struct AVPacket {
1378  /**
1379  * A reference to the reference-counted buffer where the packet data is
1380  * stored.
1381  * May be NULL, then the packet data is not reference-counted.
1382  */
1384  /**
1385  * Presentation timestamp in AVStream->time_base units; the time at which
1386  * the decompressed packet will be presented to the user.
1387  * Can be AV_NOPTS_VALUE if it is not stored in the file.
1388  * pts MUST be larger or equal to dts as presentation cannot happen before
1389  * decompression, unless one wants to view hex dumps. Some formats misuse
1390  * the terms dts and pts/cts to mean something different. Such timestamps
1391  * must be converted to true pts/dts before they are stored in AVPacket.
1392  */
1393  int64_t pts;
1394  /**
1395  * Decompression timestamp in AVStream->time_base units; the time at which
1396  * the packet is decompressed.
1397  * Can be AV_NOPTS_VALUE if it is not stored in the file.
1398  */
1399  int64_t dts;
1401  int size;
1403  /**
1404  * A combination of AV_PKT_FLAG values
1405  */
1406  int flags;
1407  /**
1408  * Additional packet data that can be provided by the container.
1409  * Packet can contain several types of side information.
1410  */
1413 
1414  /**
1415  * Duration of this packet in AVStream->time_base units, 0 if unknown.
1416  * Equals next_pts - this_pts in presentation order.
1417  */
1418  int64_t duration;
1419 
1420  int64_t pos; ///< byte position in stream, -1 if unknown
1421 
1422 #if FF_API_CONVERGENCE_DURATION
1423  /**
1424  * @deprecated Same as the duration field, but as int64_t. This was required
1425  * for Matroska subtitles, whose duration values could overflow when the
1426  * duration field was still an int.
1427  */
1430 #endif
1431 } AVPacket;
1432 #define AV_PKT_FLAG_KEY 0x0001 ///< The packet contains a keyframe
1433 #define AV_PKT_FLAG_CORRUPT 0x0002 ///< The packet content is corrupted
1434 /**
1435  * Flag is used to discard packets which are required to maintain valid
1436  * decoder state but are not required for output and should be dropped
1437  * after decoding.
1438  **/
1439 #define AV_PKT_FLAG_DISCARD 0x0004
1440 /**
1441  * The packet comes from a trusted source.
1442  *
1443  * Otherwise-unsafe constructs such as arbitrary pointers to data
1444  * outside the packet may be followed.
1445  */
1446 #define AV_PKT_FLAG_TRUSTED 0x0008
1447 /**
1448  * Flag is used to indicate packets that contain frames that can
1449  * be discarded by the decoder. I.e. Non-reference frames.
1450  */
1451 #define AV_PKT_FLAG_DISPOSABLE 0x0010
1452 
1453 
1459 };
1460 /**
1461  * @}
1462  */
1463 
1464 struct AVCodecInternal;
1465 
1469  AV_FIELD_TT, //< Top coded_first, top displayed first
1470  AV_FIELD_BB, //< Bottom coded first, bottom displayed first
1471  AV_FIELD_TB, //< Top coded first, bottom displayed first
1472  AV_FIELD_BT, //< Bottom coded first, top displayed first
1473 };
1474 
1475 /**
1476  * main external API structure.
1477  * New fields can be added to the end with minor version bumps.
1478  * Removal, reordering and changes to existing fields require a major
1479  * version bump.
1480  * You can use AVOptions (av_opt* / av_set/get*()) to access these fields from user
1481  * applications.
1482  * The name string for AVOptions options matches the associated command line
1483  * parameter name and can be found in libavcodec/options_table.h
1484  * The AVOption/command line parameter names differ in some cases from the C
1485  * structure field names for historic reasons or brevity.
1486  * sizeof(AVCodecContext) must not be used outside libav*.
1487  */
1488 typedef struct AVCodecContext {
1489  /**
1490  * information on struct for av_log
1491  * - set by avcodec_alloc_context3
1492  */
1495 
1496  enum AVMediaType codec_type; /* see AVMEDIA_TYPE_xxx */
1497  const struct AVCodec *codec;
1498  enum AVCodecID codec_id; /* see AV_CODEC_ID_xxx */
1499 
1500  /**
1501  * fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A').
1502  * This is used to work around some encoder bugs.
1503  * A demuxer should set this to what is stored in the field used to identify the codec.
1504  * If there are multiple such fields in a container then the demuxer should choose the one
1505  * which maximizes the information about the used codec.
1506  * If the codec tag field in a container is larger than 32 bits then the demuxer should
1507  * remap the longer ID to 32 bits with a table or other structure. Alternatively a new
1508  * extra_codec_tag + size could be added but for this a clear advantage must be demonstrated
1509  * first.
1510  * - encoding: Set by user, if not then the default based on codec_id will be used.
1511  * - decoding: Set by user, will be converted to uppercase by libavcodec during init.
1512  */
1513  unsigned int codec_tag;
1514 
1515  void *priv_data;
1516 
1517  /**
1518  * Private context used for internal data.
1519  *
1520  * Unlike priv_data, this is not codec-specific. It is used in general
1521  * libavcodec functions.
1522  */
1523  struct AVCodecInternal *internal;
1524 
1525  /**
1526  * Private data of the user, can be used to carry app specific stuff.
1527  * - encoding: Set by user.
1528  * - decoding: Set by user.
1529  */
1530  void *opaque;
1531 
1532  /**
1533  * the average bitrate
1534  * - encoding: Set by user; unused for constant quantizer encoding.
1535  * - decoding: Set by user, may be overwritten by libavcodec
1536  * if this info is available in the stream
1537  */
1538  int64_t bit_rate;
1539 
1540  /**
1541  * number of bits the bitstream is allowed to diverge from the reference.
1542  * the reference can be CBR (for CBR pass1) or VBR (for pass2)
1543  * - encoding: Set by user; unused for constant quantizer encoding.
1544  * - decoding: unused
1545  */
1547 
1548  /**
1549  * Global quality for codecs which cannot change it per frame.
1550  * This should be proportional to MPEG-1/2/4 qscale.
1551  * - encoding: Set by user.
1552  * - decoding: unused
1553  */
1555 
1556  /**
1557  * - encoding: Set by user.
1558  * - decoding: unused
1559  */
1561 #define FF_COMPRESSION_DEFAULT -1
1562 
1563  /**
1564  * AV_CODEC_FLAG_*.
1565  * - encoding: Set by user.
1566  * - decoding: Set by user.
1567  */
1568  int flags;
1569 
1570  /**
1571  * AV_CODEC_FLAG2_*
1572  * - encoding: Set by user.
1573  * - decoding: Set by user.
1574  */
1575  int flags2;
1576 
1577  /**
1578  * some codecs need / can use extradata like Huffman tables.
1579  * MJPEG: Huffman tables
1580  * rv10: additional flags
1581  * MPEG-4: global headers (they can be in the bitstream or here)
1582  * The allocated memory should be AV_INPUT_BUFFER_PADDING_SIZE bytes larger
1583  * than extradata_size to avoid problems if it is read with the bitstream reader.
1584  * The bytewise contents of extradata must not depend on the architecture or CPU endianness.
1585  * - encoding: Set/allocated/freed by libavcodec.
1586  * - decoding: Set/allocated/freed by user.
1587  */
1590 
1591  /**
1592  * This is the fundamental unit of time (in seconds) in terms
1593  * of which frame timestamps are represented. For fixed-fps content,
1594  * timebase should be 1/framerate and timestamp increments should be
1595  * identically 1.
1596  * This often, but not always is the inverse of the frame rate or field rate
1597  * for video. 1/time_base is not the average frame rate if the frame rate is not
1598  * constant.
1599  *
1600  * Like containers, elementary streams also can store timestamps, 1/time_base
1601  * is the unit in which these timestamps are specified.
1602  * As example of such codec time base see ISO/IEC 14496-2:2001(E)
1603  * vop_time_increment_resolution and fixed_vop_rate
1604  * (fixed_vop_rate == 0 implies that it is different from the framerate)
1605  *
1606  * - encoding: MUST be set by user.
1607  * - decoding: the use of this field for decoding is deprecated.
1608  * Use framerate instead.
1609  */
1611 
1612  /**
1613  * For some codecs, the time base is closer to the field rate than the frame rate.
1614  * Most notably, H.264 and MPEG-2 specify time_base as half of frame duration
1615  * if no telecine is used ...
1616  *
1617  * Set to time_base ticks per frame. Default 1, e.g., H.264/MPEG-2 set it to 2.
1618  */
1620 
1621  /**
1622  * Codec delay.
1623  *
1624  * Encoding: Number of frames delay there will be from the encoder input to
1625  * the decoder output. (we assume the decoder matches the spec)
1626  * Decoding: Number of frames delay in addition to what a standard decoder
1627  * as specified in the spec would produce.
1628  *
1629  * Video:
1630  * Number of frames the decoded output will be delayed relative to the
1631  * encoded input.
1632  *
1633  * Audio:
1634  * For encoding, this field is unused (see initial_padding).
1635  *
1636  * For decoding, this is the number of samples the decoder needs to
1637  * output before the decoder's output is valid. When seeking, you should
1638  * start decoding this many samples prior to your desired seek point.
1639  *
1640  * - encoding: Set by libavcodec.
1641  * - decoding: Set by libavcodec.
1642  */
1643  int delay;
1644 
1645 
1646  /* video only */
1647  /**
1648  * picture width / height.
1649  *
1650  * @note Those fields may not match the values of the last
1651  * AVFrame output by avcodec_decode_video2 due frame
1652  * reordering.
1653  *
1654  * - encoding: MUST be set by user.
1655  * - decoding: May be set by the user before opening the decoder if known e.g.
1656  * from the container. Some decoders will require the dimensions
1657  * to be set by the caller. During decoding, the decoder may
1658  * overwrite those values as required while parsing the data.
1659  */
1661 
1662  /**
1663  * Bitstream width / height, may be different from width/height e.g. when
1664  * the decoded frame is cropped before being output or lowres is enabled.
1665  *
1666  * @note Those field may not match the value of the last
1667  * AVFrame output by avcodec_receive_frame() due frame
1668  * reordering.
1669  *
1670  * - encoding: unused
1671  * - decoding: May be set by the user before opening the decoder if known
1672  * e.g. from the container. During decoding, the decoder may
1673  * overwrite those values as required while parsing the data.
1674  */
1676 
1677  /**
1678  * the number of pictures in a group of pictures, or 0 for intra_only
1679  * - encoding: Set by user.
1680  * - decoding: unused
1681  */
1683 
1684  /**
1685  * Pixel format, see AV_PIX_FMT_xxx.
1686  * May be set by the demuxer if known from headers.
1687  * May be overridden by the decoder if it knows better.
1688  *
1689  * @note This field may not match the value of the last
1690  * AVFrame output by avcodec_receive_frame() due frame
1691  * reordering.
1692  *
1693  * - encoding: Set by user.
1694  * - decoding: Set by user if known, overridden by libavcodec while
1695  * parsing the data.
1696  */
1698 
1699  /**
1700  * If non NULL, 'draw_horiz_band' is called by the libavcodec
1701  * decoder to draw a horizontal band. It improves cache usage. Not
1702  * all codecs can do that. You must check the codec capabilities
1703  * beforehand.
1704  * When multithreading is used, it may be called from multiple threads
1705  * at the same time; threads might draw different parts of the same AVFrame,
1706  * or multiple AVFrames, and there is no guarantee that slices will be drawn
1707  * in order.
1708  * The function is also used by hardware acceleration APIs.
1709  * It is called at least once during frame decoding to pass
1710  * the data needed for hardware render.
1711  * In that mode instead of pixel data, AVFrame points to
1712  * a structure specific to the acceleration API. The application
1713  * reads the structure and can change some fields to indicate progress
1714  * or mark state.
1715  * - encoding: unused
1716  * - decoding: Set by user.
1717  * @param height the height of the slice
1718  * @param y the y position of the slice
1719  * @param type 1->top field, 2->bottom field, 3->frame
1720  * @param offset offset into the AVFrame.data from which the slice should be read
1721  */
1723  const AVFrame *src, int offset[AV_NUM_DATA_POINTERS],
1724  int y, int type, int height);
1725 
1726  /**
1727  * callback to negotiate the pixelFormat
1728  * @param fmt is the list of formats which are supported by the codec,
1729  * it is terminated by -1 as 0 is a valid format, the formats are ordered by quality.
1730  * The first is always the native one.
1731  * @note The callback may be called again immediately if initialization for
1732  * the selected (hardware-accelerated) pixel format failed.
1733  * @warning Behavior is undefined if the callback returns a value not
1734  * in the fmt list of formats.
1735  * @return the chosen format
1736  * - encoding: unused
1737  * - decoding: Set by user, if not set the native format will be chosen.
1738  */
1739  enum AVPixelFormat (*get_format)(struct AVCodecContext *s, const enum AVPixelFormat * fmt);
1740 
1741  /**
1742  * maximum number of B-frames between non-B-frames
1743  * Note: The output will be delayed by max_b_frames+1 relative to the input.
1744  * - encoding: Set by user.
1745  * - decoding: unused
1746  */
1748 
1749  /**
1750  * qscale factor between IP and B-frames
1751  * If > 0 then the last P-frame quantizer will be used (q= lastp_q*factor+offset).
1752  * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1753  * - encoding: Set by user.
1754  * - decoding: unused
1755  */
1757 
1758 #if FF_API_PRIVATE_OPT
1759  /** @deprecated use encoder private options instead */
1762 #endif
1763 
1764  /**
1765  * qscale offset between IP and B-frames
1766  * - encoding: Set by user.
1767  * - decoding: unused
1768  */
1770 
1771  /**
1772  * Size of the frame reordering buffer in the decoder.
1773  * For MPEG-2 it is 1 IPB or 0 low delay IP.
1774  * - encoding: Set by libavcodec.
1775  * - decoding: Set by libavcodec.
1776  */
1778 
1779 #if FF_API_PRIVATE_OPT
1780  /** @deprecated use encoder private options instead */
1783 #endif
1784 
1785  /**
1786  * qscale factor between P- and I-frames
1787  * If > 0 then the last P-frame quantizer will be used (q = lastp_q * factor + offset).
1788  * If < 0 then normal ratecontrol will be done (q= -normal_q*factor+offset).
1789  * - encoding: Set by user.
1790  * - decoding: unused
1791  */
1793 
1794  /**
1795  * qscale offset between P and I-frames
1796  * - encoding: Set by user.
1797  * - decoding: unused
1798  */
1800 
1801  /**
1802  * luminance masking (0-> disabled)
1803  * - encoding: Set by user.
1804  * - decoding: unused
1805  */
1807 
1808  /**
1809  * temporary complexity masking (0-> disabled)
1810  * - encoding: Set by user.
1811  * - decoding: unused
1812  */
1814 
1815  /**
1816  * spatial complexity masking (0-> disabled)
1817  * - encoding: Set by user.
1818  * - decoding: unused
1819  */
1821 
1822  /**
1823  * p block masking (0-> disabled)
1824  * - encoding: Set by user.
1825  * - decoding: unused
1826  */
1827  float p_masking;
1828 
1829  /**
1830  * darkness masking (0-> disabled)
1831  * - encoding: Set by user.
1832  * - decoding: unused
1833  */
1835 
1836  /**
1837  * slice count
1838  * - encoding: Set by libavcodec.
1839  * - decoding: Set by user (or 0).
1840  */
1842 
1843 #if FF_API_PRIVATE_OPT
1844  /** @deprecated use encoder private options instead */
1847 #define FF_PRED_LEFT 0
1848 #define FF_PRED_PLANE 1
1849 #define FF_PRED_MEDIAN 2
1850 #endif
1851 
1852  /**
1853  * slice offsets in the frame in bytes
1854  * - encoding: Set/allocated by libavcodec.
1855  * - decoding: Set/allocated by user (or NULL).
1856  */
1858 
1859  /**
1860  * sample aspect ratio (0 if unknown)
1861  * That is the width of a pixel divided by the height of the pixel.
1862  * Numerator and denominator must be relatively prime and smaller than 256 for some video standards.
1863  * - encoding: Set by user.
1864  * - decoding: Set by libavcodec.
1865  */
1867 
1868  /**
1869  * motion estimation comparison function
1870  * - encoding: Set by user.
1871  * - decoding: unused
1872  */
1873  int me_cmp;
1874  /**
1875  * subpixel motion estimation comparison function
1876  * - encoding: Set by user.
1877  * - decoding: unused
1878  */
1880  /**
1881  * macroblock comparison function (not supported yet)
1882  * - encoding: Set by user.
1883  * - decoding: unused
1884  */
1885  int mb_cmp;
1886  /**
1887  * interlaced DCT comparison function
1888  * - encoding: Set by user.
1889  * - decoding: unused
1890  */
1892 #define FF_CMP_SAD 0
1893 #define FF_CMP_SSE 1
1894 #define FF_CMP_SATD 2
1895 #define FF_CMP_DCT 3
1896 #define FF_CMP_PSNR 4
1897 #define FF_CMP_BIT 5
1898 #define FF_CMP_RD 6
1899 #define FF_CMP_ZERO 7
1900 #define FF_CMP_VSAD 8
1901 #define FF_CMP_VSSE 9
1902 #define FF_CMP_NSSE 10
1903 #define FF_CMP_W53 11
1904 #define FF_CMP_W97 12
1905 #define FF_CMP_DCTMAX 13
1906 #define FF_CMP_DCT264 14
1907 #define FF_CMP_MEDIAN_SAD 15
1908 #define FF_CMP_CHROMA 256
1909 
1910  /**
1911  * ME diamond size & shape
1912  * - encoding: Set by user.
1913  * - decoding: unused
1914  */
1916 
1917  /**
1918  * amount of previous MV predictors (2a+1 x 2a+1 square)
1919  * - encoding: Set by user.
1920  * - decoding: unused
1921  */
1923 
1924 #if FF_API_PRIVATE_OPT
1925  /** @deprecated use encoder private options instead */
1927  int pre_me;
1928 #endif
1929 
1930  /**
1931  * motion estimation prepass comparison function
1932  * - encoding: Set by user.
1933  * - decoding: unused
1934  */
1936 
1937  /**
1938  * ME prepass diamond size & shape
1939  * - encoding: Set by user.
1940  * - decoding: unused
1941  */
1943 
1944  /**
1945  * subpel ME quality
1946  * - encoding: Set by user.
1947  * - decoding: unused
1948  */
1950 
1951  /**
1952  * maximum motion estimation search range in subpel units
1953  * If 0 then no limit.
1954  *
1955  * - encoding: Set by user.
1956  * - decoding: unused
1957  */
1959 
1960  /**
1961  * slice flags
1962  * - encoding: unused
1963  * - decoding: Set by user.
1964  */
1966 #define SLICE_FLAG_CODED_ORDER 0x0001 ///< draw_horiz_band() is called in coded order instead of display
1967 #define SLICE_FLAG_ALLOW_FIELD 0x0002 ///< allow draw_horiz_band() with field slices (MPEG-2 field pics)
1968 #define SLICE_FLAG_ALLOW_PLANE 0x0004 ///< allow draw_horiz_band() with 1 component at a time (SVQ1)
1969 
1970  /**
1971  * macroblock decision mode
1972  * - encoding: Set by user.
1973  * - decoding: unused
1974  */
1976 #define FF_MB_DECISION_SIMPLE 0 ///< uses mb_cmp
1977 #define FF_MB_DECISION_BITS 1 ///< chooses the one which needs the fewest bits
1978 #define FF_MB_DECISION_RD 2 ///< rate distortion
1979 
1980  /**
1981  * custom intra quantization matrix
1982  * - encoding: Set by user, can be NULL.
1983  * - decoding: Set by libavcodec.
1984  */
1985  uint16_t *intra_matrix;
1986 
1987  /**
1988  * custom inter quantization matrix
1989  * - encoding: Set by user, can be NULL.
1990  * - decoding: Set by libavcodec.
1991  */
1992  uint16_t *inter_matrix;
1993 
1994 #if FF_API_PRIVATE_OPT
1995  /** @deprecated use encoder private options instead */
1998 
1999  /** @deprecated use encoder private options instead */
2002 #endif
2003 
2004  /**
2005  * precision of the intra DC coefficient - 8
2006  * - encoding: Set by user.
2007  * - decoding: Set by libavcodec
2008  */
2010 
2011  /**
2012  * Number of macroblock rows at the top which are skipped.
2013  * - encoding: unused
2014  * - decoding: Set by user.
2015  */
2017 
2018  /**
2019  * Number of macroblock rows at the bottom which are skipped.
2020  * - encoding: unused
2021  * - decoding: Set by user.
2022  */
2024 
2025  /**
2026  * minimum MB Lagrange multiplier
2027  * - encoding: Set by user.
2028  * - decoding: unused
2029  */
2030  int mb_lmin;
2031 
2032  /**
2033  * maximum MB Lagrange multiplier
2034  * - encoding: Set by user.
2035  * - decoding: unused
2036  */
2037  int mb_lmax;
2038 
2039 #if FF_API_PRIVATE_OPT
2040  /**
2041  * @deprecated use encoder private options instead
2042  */
2045 #endif
2046 
2047  /**
2048  * - encoding: Set by user.
2049  * - decoding: unused
2050  */
2052 
2053 #if FF_API_PRIVATE_OPT
2054  /** @deprecated use encoder private options instead */
2057 #endif
2058 
2059  /**
2060  * minimum GOP size
2061  * - encoding: Set by user.
2062  * - decoding: unused
2063  */
2065 
2066  /**
2067  * number of reference frames
2068  * - encoding: Set by user.
2069  * - decoding: Set by lavc.
2070  */
2071  int refs;
2072 
2073 #if FF_API_PRIVATE_OPT
2074  /** @deprecated use encoder private options instead */
2077 #endif
2078 
2079  /**
2080  * Note: Value depends upon the compare function used for fullpel ME.
2081  * - encoding: Set by user.
2082  * - decoding: unused
2083  */
2085 
2086 #if FF_API_PRIVATE_OPT
2087  /** @deprecated use encoder private options instead */
2090 #endif
2091 
2092  /**
2093  * Chromaticity coordinates of the source primaries.
2094  * - encoding: Set by user
2095  * - decoding: Set by libavcodec
2096  */
2098 
2099  /**
2100  * Color Transfer Characteristic.
2101  * - encoding: Set by user
2102  * - decoding: Set by libavcodec
2103  */
2105 
2106  /**
2107  * YUV colorspace type.
2108  * - encoding: Set by user
2109  * - decoding: Set by libavcodec
2110  */
2112 
2113  /**
2114  * MPEG vs JPEG YUV range.
2115  * - encoding: Set by user
2116  * - decoding: Set by libavcodec
2117  */
2119 
2120  /**
2121  * This defines the location of chroma samples.
2122  * - encoding: Set by user
2123  * - decoding: Set by libavcodec
2124  */
2126 
2127  /**
2128  * Number of slices.
2129  * Indicates number of picture subdivisions. Used for parallelized
2130  * decoding.
2131  * - encoding: Set by user
2132  * - decoding: unused
2133  */
2134  int slices;
2135 
2136  /** Field order
2137  * - encoding: set by libavcodec
2138  * - decoding: Set by user.
2139  */
2141 
2142  /* audio only */
2143  int sample_rate; ///< samples per second
2144  int channels; ///< number of audio channels
2145 
2146  /**
2147  * audio sample format
2148  * - encoding: Set by user.
2149  * - decoding: Set by libavcodec.
2150  */
2151  enum AVSampleFormat sample_fmt; ///< sample format
2152 
2153  /* The following data should not be initialized. */
2154  /**
2155  * Number of samples per channel in an audio frame.
2156  *
2157  * - encoding: set by libavcodec in avcodec_open2(). Each submitted frame
2158  * except the last must contain exactly frame_size samples per channel.
2159  * May be 0 when the codec has AV_CODEC_CAP_VARIABLE_FRAME_SIZE set, then the
2160  * frame size is not restricted.
2161  * - decoding: may be set by some decoders to indicate constant frame size
2162  */
2164 
2165  /**
2166  * Frame counter, set by libavcodec.
2167  *
2168  * - decoding: total number of frames returned from the decoder so far.
2169  * - encoding: total number of frames passed to the encoder so far.
2170  *
2171  * @note the counter is not incremented if encoding/decoding resulted in
2172  * an error.
2173  */
2175 
2176  /**
2177  * number of bytes per packet if constant and known or 0
2178  * Used by some WAV based audio codecs.
2179  */
2181 
2182  /**
2183  * Audio cutoff bandwidth (0 means "automatic")
2184  * - encoding: Set by user.
2185  * - decoding: unused
2186  */
2187  int cutoff;
2188 
2189  /**
2190  * Audio channel layout.
2191  * - encoding: set by user.
2192  * - decoding: set by user, may be overwritten by libavcodec.
2193  */
2194  uint64_t channel_layout;
2195 
2196  /**
2197  * Request decoder to use this channel layout if it can (0 for default)
2198  * - encoding: unused
2199  * - decoding: Set by user.
2200  */
2202 
2203  /**
2204  * Type of service that the audio stream conveys.
2205  * - encoding: Set by user.
2206  * - decoding: Set by libavcodec.
2207  */
2209 
2210  /**
2211  * desired sample format
2212  * - encoding: Not used.
2213  * - decoding: Set by user.
2214  * Decoder will decode to this format if it can.
2215  */
2217 
2218  /**
2219  * This callback is called at the beginning of each frame to get data
2220  * buffer(s) for it. There may be one contiguous buffer for all the data or
2221  * there may be a buffer per each data plane or anything in between. What
2222  * this means is, you may set however many entries in buf[] you feel necessary.
2223  * Each buffer must be reference-counted using the AVBuffer API (see description
2224  * of buf[] below).
2225  *
2226  * The following fields will be set in the frame before this callback is
2227  * called:
2228  * - format
2229  * - width, height (video only)
2230  * - sample_rate, channel_layout, nb_samples (audio only)
2231  * Their values may differ from the corresponding values in
2232  * AVCodecContext. This callback must use the frame values, not the codec
2233  * context values, to calculate the required buffer size.
2234  *
2235  * This callback must fill the following fields in the frame:
2236  * - data[]
2237  * - linesize[]
2238  * - extended_data:
2239  * * if the data is planar audio with more than 8 channels, then this
2240  * callback must allocate and fill extended_data to contain all pointers
2241  * to all data planes. data[] must hold as many pointers as it can.
2242  * extended_data must be allocated with av_malloc() and will be freed in
2243  * av_frame_unref().
2244  * * otherwise extended_data must point to data
2245  * - buf[] must contain one or more pointers to AVBufferRef structures. Each of
2246  * the frame's data and extended_data pointers must be contained in these. That
2247  * is, one AVBufferRef for each allocated chunk of memory, not necessarily one
2248  * AVBufferRef per data[] entry. See: av_buffer_create(), av_buffer_alloc(),
2249  * and av_buffer_ref().
2250  * - extended_buf and nb_extended_buf must be allocated with av_malloc() by
2251  * this callback and filled with the extra buffers if there are more
2252  * buffers than buf[] can hold. extended_buf will be freed in
2253  * av_frame_unref().
2254  *
2255  * If AV_CODEC_CAP_DR1 is not set then get_buffer2() must call
2256  * avcodec_default_get_buffer2() instead of providing buffers allocated by
2257  * some other means.
2258  *
2259  * Each data plane must be aligned to the maximum required by the target
2260  * CPU.
2261  *
2262  * @see avcodec_default_get_buffer2()
2263  *
2264  * Video:
2265  *
2266  * If AV_GET_BUFFER_FLAG_REF is set in flags then the frame may be reused
2267  * (read and/or written to if it is writable) later by libavcodec.
2268  *
2269  * avcodec_align_dimensions2() should be used to find the required width and
2270  * height, as they normally need to be rounded up to the next multiple of 16.
2271  *
2272  * Some decoders do not support linesizes changing between frames.
2273  *
2274  * If frame multithreading is used and thread_safe_callbacks is set,
2275  * this callback may be called from a different thread, but not from more
2276  * than one at once. Does not need to be reentrant.
2277  *
2278  * @see avcodec_align_dimensions2()
2279  *
2280  * Audio:
2281  *
2282  * Decoders request a buffer of a particular size by setting
2283  * AVFrame.nb_samples prior to calling get_buffer2(). The decoder may,
2284  * however, utilize only part of the buffer by setting AVFrame.nb_samples
2285  * to a smaller value in the output frame.
2286  *
2287  * As a convenience, av_samples_get_buffer_size() and
2288  * av_samples_fill_arrays() in libavutil may be used by custom get_buffer2()
2289  * functions to find the required data size and to fill data pointers and
2290  * linesize. In AVFrame.linesize, only linesize[0] may be set for audio
2291  * since all planes must be the same size.
2292  *
2293  * @see av_samples_get_buffer_size(), av_samples_fill_arrays()
2294  *
2295  * - encoding: unused
2296  * - decoding: Set by libavcodec, user can override.
2297  */
2299 
2300  /**
2301  * If non-zero, the decoded audio and video frames returned from
2302  * avcodec_decode_video2() and avcodec_decode_audio4() are reference-counted
2303  * and are valid indefinitely. The caller must free them with
2304  * av_frame_unref() when they are not needed anymore.
2305  * Otherwise, the decoded frames must not be freed by the caller and are
2306  * only valid until the next decode call.
2307  *
2308  * This is always automatically enabled if avcodec_receive_frame() is used.
2309  *
2310  * - encoding: unused
2311  * - decoding: set by the caller before avcodec_open2().
2312  */
2315 
2316  /* - encoding parameters */
2317  float qcompress; ///< amount of qscale change between easy & hard scenes (0.0-1.0)
2318  float qblur; ///< amount of qscale smoothing over time (0.0-1.0)
2319 
2320  /**
2321  * minimum quantizer
2322  * - encoding: Set by user.
2323  * - decoding: unused
2324  */
2325  int qmin;
2326 
2327  /**
2328  * maximum quantizer
2329  * - encoding: Set by user.
2330  * - decoding: unused
2331  */
2332  int qmax;
2333 
2334  /**
2335  * maximum quantizer difference between frames
2336  * - encoding: Set by user.
2337  * - decoding: unused
2338  */
2340 
2341  /**
2342  * decoder bitstream buffer size
2343  * - encoding: Set by user.
2344  * - decoding: unused
2345  */
2347 
2348  /**
2349  * ratecontrol override, see RcOverride
2350  * - encoding: Allocated/set/freed by user.
2351  * - decoding: unused
2352  */
2355 
2356  /**
2357  * maximum bitrate
2358  * - encoding: Set by user.
2359  * - decoding: Set by user, may be overwritten by libavcodec.
2360  */
2361  int64_t rc_max_rate;
2362 
2363  /**
2364  * minimum bitrate
2365  * - encoding: Set by user.
2366  * - decoding: unused
2367  */
2368  int64_t rc_min_rate;
2369 
2370  /**
2371  * Ratecontrol attempt to use, at maximum, <value> of what can be used without an underflow.
2372  * - encoding: Set by user.
2373  * - decoding: unused.
2374  */
2376 
2377  /**
2378  * Ratecontrol attempt to use, at least, <value> times the amount needed to prevent a vbv overflow.
2379  * - encoding: Set by user.
2380  * - decoding: unused.
2381  */
2383 
2384  /**
2385  * Number of bits which should be loaded into the rc buffer before decoding starts.
2386  * - encoding: Set by user.
2387  * - decoding: unused
2388  */
2390 
2391 #if FF_API_CODER_TYPE
2392 #define FF_CODER_TYPE_VLC 0
2393 #define FF_CODER_TYPE_AC 1
2394 #define FF_CODER_TYPE_RAW 2
2395 #define FF_CODER_TYPE_RLE 3
2396  /**
2397  * @deprecated use encoder private options instead
2398  */
2401 #endif /* FF_API_CODER_TYPE */
2402 
2403 #if FF_API_PRIVATE_OPT
2404  /** @deprecated use encoder private options instead */
2407 #endif
2408 
2409 #if FF_API_PRIVATE_OPT
2410  /** @deprecated use encoder private options instead */
2413 
2414  /** @deprecated use encoder private options instead */
2417 
2418  /** @deprecated use encoder private options instead */
2421 
2422  /** @deprecated use encoder private options instead */
2425 #endif /* FF_API_PRIVATE_OPT */
2426 
2427  /**
2428  * trellis RD quantization
2429  * - encoding: Set by user.
2430  * - decoding: unused
2431  */
2432  int trellis;
2433 
2434 #if FF_API_PRIVATE_OPT
2435  /** @deprecated use encoder private options instead */
2438 
2439  /** @deprecated use encoder private options instead */
2442 
2443  /** @deprecated use encoder private options instead */
2446 #endif
2447 
2448 #if FF_API_RTP_CALLBACK
2449  /**
2450  * @deprecated unused
2451  */
2452  /* The RTP callback: This function is called */
2453  /* every time the encoder has a packet to send. */
2454  /* It depends on the encoder if the data starts */
2455  /* with a Start Code (it should). H.263 does. */
2456  /* mb_nb contains the number of macroblocks */
2457  /* encoded in the RTP payload. */
2459  void (*rtp_callback)(struct AVCodecContext *avctx, void *data, int size, int mb_nb);
2460 #endif
2461 
2462 #if FF_API_PRIVATE_OPT
2463  /** @deprecated use encoder private options instead */
2465  int rtp_payload_size; /* The size of the RTP payload: the coder will */
2466  /* do its best to deliver a chunk with size */
2467  /* below rtp_payload_size, the chunk will start */
2468  /* with a start code on some codecs like H.263. */
2469  /* This doesn't take account of any particular */
2470  /* headers inside the transmitted RTP payload. */
2471 #endif
2472 
2473 #if FF_API_STAT_BITS
2474  /* statistics, used for 2-pass encoding */
2476  int mv_bits;
2484  int i_count;
2486  int p_count;
2491 
2492  /** @deprecated this field is unused */
2495 #endif
2496 
2497  /**
2498  * pass1 encoding statistics output buffer
2499  * - encoding: Set by libavcodec.
2500  * - decoding: unused
2501  */
2502  char *stats_out;
2503 
2504  /**
2505  * pass2 encoding statistics input buffer
2506  * Concatenated stuff from stats_out of pass1 should be placed here.
2507  * - encoding: Allocated/set/freed by user.
2508  * - decoding: unused
2509  */
2510  char *stats_in;
2511 
2512  /**
2513  * Work around bugs in encoders which sometimes cannot be detected automatically.
2514  * - encoding: Set by user
2515  * - decoding: Set by user
2516  */
2518 #define FF_BUG_AUTODETECT 1 ///< autodetection
2519 #define FF_BUG_XVID_ILACE 4
2520 #define FF_BUG_UMP4 8
2521 #define FF_BUG_NO_PADDING 16
2522 #define FF_BUG_AMV 32
2523 #define FF_BUG_QPEL_CHROMA 64
2524 #define FF_BUG_STD_QPEL 128
2525 #define FF_BUG_QPEL_CHROMA2 256
2526 #define FF_BUG_DIRECT_BLOCKSIZE 512
2527 #define FF_BUG_EDGE 1024
2528 #define FF_BUG_HPEL_CHROMA 2048
2529 #define FF_BUG_DC_CLIP 4096
2530 #define FF_BUG_MS 8192 ///< Work around various bugs in Microsoft's broken decoders.
2531 #define FF_BUG_TRUNCATED 16384
2532 #define FF_BUG_IEDGE 32768
2533 
2534  /**
2535  * strictly follow the standard (MPEG-4, ...).
2536  * - encoding: Set by user.
2537  * - decoding: Set by user.
2538  * Setting this to STRICT or higher means the encoder and decoder will
2539  * generally do stupid things, whereas setting it to unofficial or lower
2540  * will mean the encoder might produce output that is not supported by all
2541  * spec-compliant decoders. Decoders don't differentiate between normal,
2542  * unofficial and experimental (that is, they always try to decode things
2543  * when they can) unless they are explicitly asked to behave stupidly
2544  * (=strictly conform to the specs)
2545  */
2547 #define FF_COMPLIANCE_VERY_STRICT 2 ///< Strictly conform to an older more strict version of the spec or reference software.
2548 #define FF_COMPLIANCE_STRICT 1 ///< Strictly conform to all the things in the spec no matter what consequences.
2549 #define FF_COMPLIANCE_NORMAL 0
2550 #define FF_COMPLIANCE_UNOFFICIAL -1 ///< Allow unofficial extensions
2551 #define FF_COMPLIANCE_EXPERIMENTAL -2 ///< Allow nonstandardized experimental things.
2552 
2553  /**
2554  * error concealment flags
2555  * - encoding: unused
2556  * - decoding: Set by user.
2557  */
2559 #define FF_EC_GUESS_MVS 1
2560 #define FF_EC_DEBLOCK 2
2561 #define FF_EC_FAVOR_INTER 256
2562 
2563  /**
2564  * debug
2565  * - encoding: Set by user.
2566  * - decoding: Set by user.
2567  */
2568  int debug;
2569 #define FF_DEBUG_PICT_INFO 1
2570 #define FF_DEBUG_RC 2
2571 #define FF_DEBUG_BITSTREAM 4
2572 #define FF_DEBUG_MB_TYPE 8
2573 #define FF_DEBUG_QP 16
2574 #if FF_API_DEBUG_MV
2575 /**
2576  * @deprecated this option does nothing
2577  */
2578 #define FF_DEBUG_MV 32
2579 #endif
2580 #define FF_DEBUG_DCT_COEFF 0x00000040
2581 #define FF_DEBUG_SKIP 0x00000080
2582 #define FF_DEBUG_STARTCODE 0x00000100
2583 #define FF_DEBUG_ER 0x00000400
2584 #define FF_DEBUG_MMCO 0x00000800
2585 #define FF_DEBUG_BUGS 0x00001000
2586 #if FF_API_DEBUG_MV
2587 #define FF_DEBUG_VIS_QP 0x00002000
2588 #define FF_DEBUG_VIS_MB_TYPE 0x00004000
2589 #endif
2590 #define FF_DEBUG_BUFFERS 0x00008000
2591 #define FF_DEBUG_THREADS 0x00010000
2592 #define FF_DEBUG_GREEN_MD 0x00800000
2593 #define FF_DEBUG_NOMC 0x01000000
2594 
2595 #if FF_API_DEBUG_MV
2596  /**
2597  * debug
2598  * - encoding: Set by user.
2599  * - decoding: Set by user.
2600  */
2601  int debug_mv;
2602 #define FF_DEBUG_VIS_MV_P_FOR 0x00000001 // visualize forward predicted MVs of P-frames
2603 #define FF_DEBUG_VIS_MV_B_FOR 0x00000002 // visualize forward predicted MVs of B-frames
2604 #define FF_DEBUG_VIS_MV_B_BACK 0x00000004 // visualize backward predicted MVs of B-frames
2605 #endif
2606 
2607  /**
2608  * Error recognition; may misdetect some more or less valid parts as errors.
2609  * - encoding: unused
2610  * - decoding: Set by user.
2611  */
2613 
2614 /**
2615  * Verify checksums embedded in the bitstream (could be of either encoded or
2616  * decoded data, depending on the codec) and print an error message on mismatch.
2617  * If AV_EF_EXPLODE is also set, a mismatching checksum will result in the
2618  * decoder returning an error.
2619  */
2620 #define AV_EF_CRCCHECK (1<<0)
2621 #define AV_EF_BITSTREAM (1<<1) ///< detect bitstream specification deviations
2622 #define AV_EF_BUFFER (1<<2) ///< detect improper bitstream length
2623 #define AV_EF_EXPLODE (1<<3) ///< abort decoding on minor error detection
2624 
2625 #define AV_EF_IGNORE_ERR (1<<15) ///< ignore errors and continue
2626 #define AV_EF_CAREFUL (1<<16) ///< consider things that violate the spec, are fast to calculate and have not been seen in the wild as errors
2627 #define AV_EF_COMPLIANT (1<<17) ///< consider all spec non compliances as errors
2628 #define AV_EF_AGGRESSIVE (1<<18) ///< consider things that a sane encoder should not do as an error
2629 
2630 
2631  /**
2632  * opaque 64-bit number (generally a PTS) that will be reordered and
2633  * output in AVFrame.reordered_opaque
2634  * - encoding: unused
2635  * - decoding: Set by user.
2636  */
2638 
2639  /**
2640  * Hardware accelerator in use
2641  * - encoding: unused.
2642  * - decoding: Set by libavcodec
2643  */
2644  const struct AVHWAccel *hwaccel;
2645 
2646  /**
2647  * Hardware accelerator context.
2648  * For some hardware accelerators, a global context needs to be
2649  * provided by the user. In that case, this holds display-dependent
2650  * data FFmpeg cannot instantiate itself. Please refer to the
2651  * FFmpeg HW accelerator documentation to know how to fill this
2652  * is. e.g. for VA API, this is a struct vaapi_context.
2653  * - encoding: unused
2654  * - decoding: Set by user
2655  */
2657 
2658  /**
2659  * error
2660  * - encoding: Set by libavcodec if flags & AV_CODEC_FLAG_PSNR.
2661  * - decoding: unused
2662  */
2664 
2665  /**
2666  * DCT algorithm, see FF_DCT_* below
2667  * - encoding: Set by user.
2668  * - decoding: unused
2669  */
2671 #define FF_DCT_AUTO 0
2672 #define FF_DCT_FASTINT 1
2673 #define FF_DCT_INT 2
2674 #define FF_DCT_MMX 3
2675 #define FF_DCT_ALTIVEC 5
2676 #define FF_DCT_FAAN 6
2677 
2678  /**
2679  * IDCT algorithm, see FF_IDCT_* below.
2680  * - encoding: Set by user.
2681  * - decoding: Set by user.
2682  */
2684 #define FF_IDCT_AUTO 0
2685 #define FF_IDCT_INT 1
2686 #define FF_IDCT_SIMPLE 2
2687 #define FF_IDCT_SIMPLEMMX 3
2688 #define FF_IDCT_ARM 7
2689 #define FF_IDCT_ALTIVEC 8
2690 #define FF_IDCT_SIMPLEARM 10
2691 #define FF_IDCT_XVID 14
2692 #define FF_IDCT_SIMPLEARMV5TE 16
2693 #define FF_IDCT_SIMPLEARMV6 17
2694 #define FF_IDCT_FAAN 20
2695 #define FF_IDCT_SIMPLENEON 22
2696 #define FF_IDCT_NONE 24 /* Used by XvMC to extract IDCT coefficients with FF_IDCT_PERM_NONE */
2697 #define FF_IDCT_SIMPLEAUTO 128
2698 
2699  /**
2700  * bits per sample/pixel from the demuxer (needed for huffyuv).
2701  * - encoding: Set by libavcodec.
2702  * - decoding: Set by user.
2703  */
2705 
2706  /**
2707  * Bits per sample/pixel of internal libavcodec pixel/sample format.
2708  * - encoding: set by user.
2709  * - decoding: set by libavcodec.
2710  */
2712 
2713 #if FF_API_LOWRES
2714  /**
2715  * low resolution decoding, 1-> 1/2 size, 2->1/4 size
2716  * - encoding: unused
2717  * - decoding: Set by user.
2718  */
2719  int lowres;
2720 #endif
2721 
2722 #if FF_API_CODED_FRAME
2723  /**
2724  * the picture in the bitstream
2725  * - encoding: Set by libavcodec.
2726  * - decoding: unused
2727  *
2728  * @deprecated use the quality factor packet side data instead
2729  */
2731 #endif
2732 
2733  /**
2734  * thread count
2735  * is used to decide how many independent tasks should be passed to execute()
2736  * - encoding: Set by user.
2737  * - decoding: Set by user.
2738  */
2740 
2741  /**
2742  * Which multithreading methods to use.
2743  * Use of FF_THREAD_FRAME will increase decoding delay by one frame per thread,
2744  * so clients which cannot provide future frames should not use it.
2745  *
2746  * - encoding: Set by user, otherwise the default is used.
2747  * - decoding: Set by user, otherwise the default is used.
2748  */
2750 #define FF_THREAD_FRAME 1 ///< Decode more than one frame at once
2751 #define FF_THREAD_SLICE 2 ///< Decode more than one part of a single frame at once
2752 
2753  /**
2754  * Which multithreading methods are in use by the codec.
2755  * - encoding: Set by libavcodec.
2756  * - decoding: Set by libavcodec.
2757  */
2759 
2760  /**
2761  * Set by the client if its custom get_buffer() callback can be called
2762  * synchronously from another thread, which allows faster multithreaded decoding.
2763  * draw_horiz_band() will be called from other threads regardless of this setting.
2764  * Ignored if the default get_buffer() is used.
2765  * - encoding: Set by user.
2766  * - decoding: Set by user.
2767  */
2769 
2770  /**
2771  * The codec may call this to execute several independent things.
2772  * It will return only after finishing all tasks.
2773  * The user may replace this with some multithreaded implementation,
2774  * the default implementation will execute the parts serially.
2775  * @param count the number of things to execute
2776  * - encoding: Set by libavcodec, user can override.
2777  * - decoding: Set by libavcodec, user can override.
2778  */
2779  int (*execute)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size);
2780 
2781  /**
2782  * The codec may call this to execute several independent things.
2783  * It will return only after finishing all tasks.
2784  * The user may replace this with some multithreaded implementation,
2785  * the default implementation will execute the parts serially.
2786  * Also see avcodec_thread_init and e.g. the --enable-pthread configure option.
2787  * @param c context passed also to func
2788  * @param count the number of things to execute
2789  * @param arg2 argument passed unchanged to func
2790  * @param ret return values of executed functions, must have space for "count" values. May be NULL.
2791  * @param func function that will be called count times, with jobnr from 0 to count-1.
2792  * threadnr will be in the range 0 to c->thread_count-1 < MAX_THREADS and so that no
2793  * two instances of func executing at the same time will have the same threadnr.
2794  * @return always 0 currently, but code should handle a future improvement where when any call to func
2795  * returns < 0 no further calls to func may be done and < 0 is returned.
2796  * - encoding: Set by libavcodec, user can override.
2797  * - decoding: Set by libavcodec, user can override.
2798  */
2799  int (*execute2)(struct AVCodecContext *c, int (*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count);
2800 
2801  /**
2802  * noise vs. sse weight for the nsse comparison function
2803  * - encoding: Set by user.
2804  * - decoding: unused
2805  */
2807 
2808  /**
2809  * profile
2810  * - encoding: Set by user.
2811  * - decoding: Set by libavcodec.
2812  */
2813  int profile;
2814 #define FF_PROFILE_UNKNOWN -99
2815 #define FF_PROFILE_RESERVED -100
2816 
2817 #define FF_PROFILE_AAC_MAIN 0
2818 #define FF_PROFILE_AAC_LOW 1
2819 #define FF_PROFILE_AAC_SSR 2
2820 #define FF_PROFILE_AAC_LTP 3
2821 #define FF_PROFILE_AAC_HE 4
2822 #define FF_PROFILE_AAC_HE_V2 28
2823 #define FF_PROFILE_AAC_LD 22
2824 #define FF_PROFILE_AAC_ELD 38
2825 #define FF_PROFILE_MPEG2_AAC_LOW 128
2826 #define FF_PROFILE_MPEG2_AAC_HE 131
2827 
2828 #define FF_PROFILE_DNXHD 0
2829 #define FF_PROFILE_DNXHR_LB 1
2830 #define FF_PROFILE_DNXHR_SQ 2
2831 #define FF_PROFILE_DNXHR_HQ 3
2832 #define FF_PROFILE_DNXHR_HQX 4
2833 #define FF_PROFILE_DNXHR_444 5
2834 
2835 #define FF_PROFILE_DTS 20
2836 #define FF_PROFILE_DTS_ES 30
2837 #define FF_PROFILE_DTS_96_24 40
2838 #define FF_PROFILE_DTS_HD_HRA 50
2839 #define FF_PROFILE_DTS_HD_MA 60
2840 #define FF_PROFILE_DTS_EXPRESS 70
2841 
2842 #define FF_PROFILE_MPEG2_422 0
2843 #define FF_PROFILE_MPEG2_HIGH 1
2844 #define FF_PROFILE_MPEG2_SS 2
2845 #define FF_PROFILE_MPEG2_SNR_SCALABLE 3
2846 #define FF_PROFILE_MPEG2_MAIN 4
2847 #define FF_PROFILE_MPEG2_SIMPLE 5
2848 
2849 #define FF_PROFILE_H264_CONSTRAINED (1<<9) // 8+1; constraint_set1_flag
2850 #define FF_PROFILE_H264_INTRA (1<<11) // 8+3; constraint_set3_flag
2851 
2852 #define FF_PROFILE_H264_BASELINE 66
2853 #define FF_PROFILE_H264_CONSTRAINED_BASELINE (66|FF_PROFILE_H264_CONSTRAINED)
2854 #define FF_PROFILE_H264_MAIN 77
2855 #define FF_PROFILE_H264_EXTENDED 88
2856 #define FF_PROFILE_H264_HIGH 100
2857 #define FF_PROFILE_H264_HIGH_10 110
2858 #define FF_PROFILE_H264_HIGH_10_INTRA (110|FF_PROFILE_H264_INTRA)
2859 #define FF_PROFILE_H264_MULTIVIEW_HIGH 118
2860 #define FF_PROFILE_H264_HIGH_422 122
2861 #define FF_PROFILE_H264_HIGH_422_INTRA (122|FF_PROFILE_H264_INTRA)
2862 #define FF_PROFILE_H264_STEREO_HIGH 128
2863 #define FF_PROFILE_H264_HIGH_444 144
2864 #define FF_PROFILE_H264_HIGH_444_PREDICTIVE 244
2865 #define FF_PROFILE_H264_HIGH_444_INTRA (244|FF_PROFILE_H264_INTRA)
2866 #define FF_PROFILE_H264_CAVLC_444 44
2867 
2868 #define FF_PROFILE_VC1_SIMPLE 0
2869 #define FF_PROFILE_VC1_MAIN 1
2870 #define FF_PROFILE_VC1_COMPLEX 2
2871 #define FF_PROFILE_VC1_ADVANCED 3
2872 
2873 #define FF_PROFILE_MPEG4_SIMPLE 0
2874 #define FF_PROFILE_MPEG4_SIMPLE_SCALABLE 1
2875 #define FF_PROFILE_MPEG4_CORE 2
2876 #define FF_PROFILE_MPEG4_MAIN 3
2877 #define FF_PROFILE_MPEG4_N_BIT 4
2878 #define FF_PROFILE_MPEG4_SCALABLE_TEXTURE 5
2879 #define FF_PROFILE_MPEG4_SIMPLE_FACE_ANIMATION 6
2880 #define FF_PROFILE_MPEG4_BASIC_ANIMATED_TEXTURE 7
2881 #define FF_PROFILE_MPEG4_HYBRID 8
2882 #define FF_PROFILE_MPEG4_ADVANCED_REAL_TIME 9
2883 #define FF_PROFILE_MPEG4_CORE_SCALABLE 10
2884 #define FF_PROFILE_MPEG4_ADVANCED_CODING 11
2885 #define FF_PROFILE_MPEG4_ADVANCED_CORE 12
2886 #define FF_PROFILE_MPEG4_ADVANCED_SCALABLE_TEXTURE 13
2887 #define FF_PROFILE_MPEG4_SIMPLE_STUDIO 14
2888 #define FF_PROFILE_MPEG4_ADVANCED_SIMPLE 15
2889 
2890 #define FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_0 1
2891 #define FF_PROFILE_JPEG2000_CSTREAM_RESTRICTION_1 2
2892 #define FF_PROFILE_JPEG2000_CSTREAM_NO_RESTRICTION 32768
2893 #define FF_PROFILE_JPEG2000_DCINEMA_2K 3
2894 #define FF_PROFILE_JPEG2000_DCINEMA_4K 4
2895 
2896 #define FF_PROFILE_VP9_0 0
2897 #define FF_PROFILE_VP9_1 1
2898 #define FF_PROFILE_VP9_2 2
2899 #define FF_PROFILE_VP9_3 3
2900 
2901 #define FF_PROFILE_HEVC_MAIN 1
2902 #define FF_PROFILE_HEVC_MAIN_10 2
2903 #define FF_PROFILE_HEVC_MAIN_STILL_PICTURE 3
2904 #define FF_PROFILE_HEVC_REXT 4
2905 
2906  /**
2907  * level
2908  * - encoding: Set by user.
2909  * - decoding: Set by libavcodec.
2910  */
2911  int level;
2912 #define FF_LEVEL_UNKNOWN -99
2913 
2914  /**
2915  * Skip loop filtering for selected frames.
2916  * - encoding: unused
2917  * - decoding: Set by user.
2918  */
2920 
2921  /**
2922  * Skip IDCT/dequantization for selected frames.
2923  * - encoding: unused
2924  * - decoding: Set by user.
2925  */
2927 
2928  /**
2929  * Skip decoding for selected frames.
2930  * - encoding: unused
2931  * - decoding: Set by user.
2932  */
2934 
2935  /**
2936  * Header containing style information for text subtitles.
2937  * For SUBTITLE_ASS subtitle type, it should contain the whole ASS
2938  * [Script Info] and [V4+ Styles] section, plus the [Events] line and
2939  * the Format line following. It shouldn't include any Dialogue line.
2940  * - encoding: Set/allocated/freed by user (before avcodec_open2())
2941  * - decoding: Set/allocated/freed by libavcodec (by avcodec_open2())
2942  */
2945 
2946 #if FF_API_VBV_DELAY
2947  /**
2948  * VBV delay coded in the last frame (in periods of a 27 MHz clock).
2949  * Used for compliant TS muxing.
2950  * - encoding: Set by libavcodec.
2951  * - decoding: unused.
2952  * @deprecated this value is now exported as a part of
2953  * AV_PKT_DATA_CPB_PROPERTIES packet side data
2954  */
2956  uint64_t vbv_delay;
2957 #endif
2958 
2959 #if FF_API_SIDEDATA_ONLY_PKT
2960  /**
2961  * Encoding only and set by default. Allow encoders to output packets
2962  * that do not contain any encoded data, only side data.
2963  *
2964  * Some encoders need to output such packets, e.g. to update some stream
2965  * parameters at the end of encoding.
2966  *
2967  * @deprecated this field disables the default behaviour and
2968  * it is kept only for compatibility.
2969  */
2972 #endif
2973 
2974  /**
2975  * Audio only. The number of "priming" samples (padding) inserted by the
2976  * encoder at the beginning of the audio. I.e. this number of leading
2977  * decoded samples must be discarded by the caller to get the original audio
2978  * without leading padding.
2979  *
2980  * - decoding: unused
2981  * - encoding: Set by libavcodec. The timestamps on the output packets are
2982  * adjusted by the encoder so that they always refer to the
2983  * first sample of the data actually contained in the packet,
2984  * including any added padding. E.g. if the timebase is
2985  * 1/samplerate and the timestamp of the first input sample is
2986  * 0, the timestamp of the first output packet will be
2987  * -initial_padding.
2988  */
2990 
2991  /**
2992  * - decoding: For codecs that store a framerate value in the compressed
2993  * bitstream, the decoder may export it here. { 0, 1} when
2994  * unknown.
2995  * - encoding: May be used to signal the framerate of CFR content to an
2996  * encoder.
2997  */
2999 
3000  /**
3001  * Nominal unaccelerated pixel format, see AV_PIX_FMT_xxx.
3002  * - encoding: unused.
3003  * - decoding: Set by libavcodec before calling get_format()
3004  */
3006 
3007  /**
3008  * Timebase in which pkt_dts/pts and AVPacket.dts/pts are.
3009  * - encoding unused.
3010  * - decoding set by user.
3011  */
3013 
3014  /**
3015  * AVCodecDescriptor
3016  * - encoding: unused.
3017  * - decoding: set by libavcodec.
3018  */
3020 
3021 #if !FF_API_LOWRES
3022  /**
3023  * low resolution decoding, 1-> 1/2 size, 2->1/4 size
3024  * - encoding: unused
3025  * - decoding: Set by user.
3026  */
3027  int lowres;
3028 #endif
3029 
3030  /**
3031  * Current statistics for PTS correction.
3032  * - decoding: maintained and used by libavcodec, not intended to be used by user apps
3033  * - encoding: unused
3034  */
3035  int64_t pts_correction_num_faulty_pts; /// Number of incorrect PTS values so far
3036  int64_t pts_correction_num_faulty_dts; /// Number of incorrect DTS values so far
3037  int64_t pts_correction_last_pts; /// PTS of the last frame
3038  int64_t pts_correction_last_dts; /// DTS of the last frame
3039 
3040  /**
3041  * Character encoding of the input subtitles file.
3042  * - decoding: set by user
3043  * - encoding: unused
3044  */
3046 
3047  /**
3048  * Subtitles character encoding mode. Formats or codecs might be adjusting
3049  * this setting (if they are doing the conversion themselves for instance).
3050  * - decoding: set by libavcodec
3051  * - encoding: unused
3052  */
3054 #define FF_SUB_CHARENC_MODE_DO_NOTHING -1 ///< do nothing (demuxer outputs a stream supposed to be already in UTF-8, or the codec is bitmap for instance)
3055 #define FF_SUB_CHARENC_MODE_AUTOMATIC 0 ///< libavcodec will select the mode itself
3056 #define FF_SUB_CHARENC_MODE_PRE_DECODER 1 ///< the AVPacket data needs to be recoded to UTF-8 before being fed to the decoder, requires iconv
3057 
3058  /**
3059  * Skip processing alpha if supported by codec.
3060  * Note that if the format uses pre-multiplied alpha (common with VP6,
3061  * and recommended due to better video quality/compression)
3062  * the image will look as if alpha-blended onto a black background.
3063  * However for formats that do not use pre-multiplied alpha
3064  * there might be serious artefacts (though e.g. libswscale currently
3065  * assumes pre-multiplied alpha anyway).
3066  *
3067  * - decoding: set by user
3068  * - encoding: unused
3069  */
3071 
3072  /**
3073  * Number of samples to skip after a discontinuity
3074  * - decoding: unused
3075  * - encoding: set by libavcodec
3076  */
3078 
3079 #if !FF_API_DEBUG_MV
3080  /**
3081  * debug motion vectors
3082  * - encoding: Set by user.
3083  * - decoding: Set by user.
3084  */
3086 #define FF_DEBUG_VIS_MV_P_FOR 0x00000001 //visualize forward predicted MVs of P frames
3087 #define FF_DEBUG_VIS_MV_B_FOR 0x00000002 //visualize forward predicted MVs of B frames
3088 #define FF_DEBUG_VIS_MV_B_BACK 0x00000004 //visualize backward predicted MVs of B frames
3089 #endif
3090 
3091  /**
3092  * custom intra quantization matrix
3093  * - encoding: Set by user, can be NULL.
3094  * - decoding: unused.
3095  */
3097 
3098  /**
3099  * dump format separator.
3100  * can be ", " or "\n " or anything else
3101  * - encoding: Set by user.
3102  * - decoding: Set by user.
3103  */
3105 
3106  /**
3107  * ',' separated list of allowed decoders.
3108  * If NULL then all are allowed
3109  * - encoding: unused
3110  * - decoding: set by user
3111  */
3113 
3114  /**
3115  * Properties of the stream that gets decoded
3116  * - encoding: unused
3117  * - decoding: set by libavcodec
3118  */
3119  unsigned properties;
3120 #define FF_CODEC_PROPERTY_LOSSLESS 0x00000001
3121 #define FF_CODEC_PROPERTY_CLOSED_CAPTIONS 0x00000002
3122 
3123  /**
3124  * Additional data associated with the entire coded stream.
3125  *
3126  * - decoding: unused
3127  * - encoding: may be set by libavcodec after avcodec_open2().
3128  */
3131 
3132  /**
3133  * A reference to the AVHWFramesContext describing the input (for encoding)
3134  * or output (decoding) frames. The reference is set by the caller and
3135  * afterwards owned (and freed) by libavcodec - it should never be read by
3136  * the caller after being set.
3137  *
3138  * - decoding: This field should be set by the caller from the get_format()
3139  * callback. The previous reference (if any) will always be
3140  * unreffed by libavcodec before the get_format() call.
3141  *
3142  * If the default get_buffer2() is used with a hwaccel pixel
3143  * format, then this AVHWFramesContext will be used for
3144  * allocating the frame buffers.
3145  *
3146  * - encoding: For hardware encoders configured to use a hwaccel pixel
3147  * format, this field should be set by the caller to a reference
3148  * to the AVHWFramesContext describing input frames.
3149  * AVHWFramesContext.format must be equal to
3150  * AVCodecContext.pix_fmt.
3151  *
3152  * This field should be set before avcodec_open2() is called.
3153  */
3155 
3156  /**
3157  * Control the form of AVSubtitle.rects[N]->ass
3158  * - decoding: set by user
3159  * - encoding: unused
3160  */
3162 #define FF_SUB_TEXT_FMT_ASS 0
3163 #if FF_API_ASS_TIMING
3164 #define FF_SUB_TEXT_FMT_ASS_WITH_TIMINGS 1
3165 #endif
3166 
3167  /**
3168  * Audio only. The amount of padding (in samples) appended by the encoder to
3169  * the end of the audio. I.e. this number of decoded samples must be
3170  * discarded by the caller from the end of the stream to get the original
3171  * audio without any trailing padding.
3172  *
3173  * - decoding: unused
3174  * - encoding: unused
3175  */
3177 
3178  /**
3179  * The number of pixels per image to maximally accept.
3180  *
3181  * - decoding: set by user
3182  * - encoding: set by user
3183  */
3184  int64_t max_pixels;
3185 
3186  /**
3187  * A reference to the AVHWDeviceContext describing the device which will
3188  * be used by a hardware encoder/decoder. The reference is set by the
3189  * caller and afterwards owned (and freed) by libavcodec.
3190  *
3191  * This should be used if either the codec device does not require
3192  * hardware frames or any that are used are to be allocated internally by
3193  * libavcodec. If the user wishes to supply any of the frames used as
3194  * encoder input or decoder output then hw_frames_ctx should be used
3195  * instead. When hw_frames_ctx is set in get_format() for a decoder, this
3196  * field will be ignored while decoding the associated stream segment, but
3197  * may again be used on a following one after another get_format() call.
3198  *
3199  * For both encoders and decoders this field should be set before
3200  * avcodec_open2() is called and must not be written to thereafter.
3201  *
3202  * Note that some decoders may require this field to be set initially in
3203  * order to support hw_frames_ctx at all - in that case, all frames
3204  * contexts used must be created on the same device.
3205  */
3207 
3208  /**
3209  * Bit set of AV_HWACCEL_FLAG_* flags, which affect hardware accelerated
3210  * decoding (if active).
3211  * - encoding: unused
3212  * - decoding: Set by user (either before avcodec_open2(), or in the
3213  * AVCodecContext.get_format callback)
3214  */
3216 
3217  /**
3218  * Video decoding only. Certain video codecs support cropping, meaning that
3219  * only a sub-rectangle of the decoded frame is intended for display. This
3220  * option controls how cropping is handled by libavcodec.
3221  *
3222  * When set to 1 (the default), libavcodec will apply cropping internally.
3223  * I.e. it will modify the output frame width/height fields and offset the
3224  * data pointers (only by as much as possible while preserving alignment, or
3225  * by the full amount if the AV_CODEC_FLAG_UNALIGNED flag is set) so that
3226  * the frames output by the decoder refer only to the cropped area. The
3227  * crop_* fields of the output frames will be zero.
3228  *
3229  * When set to 0, the width/height fields of the output frames will be set
3230  * to the coded dimensions and the crop_* fields will describe the cropping
3231  * rectangle. Applying the cropping is left to the caller.
3232  *
3233  * @warning When hardware acceleration with opaque output frames is used,
3234  * libavcodec is unable to apply cropping from the top/left border.
3235  *
3236  * @note when this option is set to zero, the width/height fields of the
3237  * AVCodecContext and output AVFrames have different meanings. The codec
3238  * context fields store display dimensions (with the coded dimensions in
3239  * coded_width/height), while the frame fields store the coded dimensions
3240  * (with the display dimensions being determined by the crop_* fields).
3241  */
3243 } AVCodecContext;
3244 
3245 #if FF_API_CODEC_GET_SET
3246 /**
3247  * Accessors for some AVCodecContext fields. These used to be provided for ABI
3248  * compatibility, and do not need to be used anymore.
3249  */
3254 
3259 
3261 unsigned av_codec_get_codec_properties(const AVCodecContext *avctx);
3262 
3263 #if FF_API_LOWRES
3265 int av_codec_get_lowres(const AVCodecContext *avctx);
3267 void av_codec_set_lowres(AVCodecContext *avctx, int val);
3268 #endif
3269 
3271 int av_codec_get_seek_preroll(const AVCodecContext *avctx);
3273 void av_codec_set_seek_preroll(AVCodecContext *avctx, int val);
3274 
3276 uint16_t *av_codec_get_chroma_intra_matrix(const AVCodecContext *avctx);
3278 void av_codec_set_chroma_intra_matrix(AVCodecContext *avctx, uint16_t *val);
3279 #endif
3280 
3281 /**
3282  * AVProfile.
3283  */
3284 typedef struct AVProfile {
3285  int profile;
3286  const char *name; ///< short name for the profile
3287 } AVProfile;
3288 
3289 enum {
3290  /**
3291  * The codec supports this format via the hw_device_ctx interface.
3292  *
3293  * When selecting this format, AVCodecContext.hw_device_ctx should
3294  * have been set to a device of the specified type before calling
3295  * avcodec_open2().
3296  */
3298  /**
3299  * The codec supports this format via the hw_frames_ctx interface.
3300  *
3301  * When selecting this format for a decoder,
3302  * AVCodecContext.hw_frames_ctx should be set to a suitable frames
3303  * context inside the get_format() callback. The frames context
3304  * must have been created on a device of the specified type.
3305  */
3307  /**
3308  * The codec supports this format by some internal method.
3309  *
3310  * This format can be selected without any additional configuration -
3311  * no device or frames context is required.
3312  */
3314  /**
3315  * The codec supports this format by some ad-hoc method.
3316  *
3317  * Additional settings and/or function calls are required. See the
3318  * codec-specific documentation for details. (Methods requiring
3319  * this sort of configuration are deprecated and others should be
3320  * used in preference.)
3321  */
3323 };
3324 
3325 typedef struct AVCodecHWConfig {
3326  /**
3327  * A hardware pixel format which the codec can use.
3328  */
3330  /**
3331  * Bit set of AV_CODEC_HW_CONFIG_METHOD_* flags, describing the possible
3332  * setup methods which can be used with this configuration.
3333  */
3334  int methods;
3335  /**
3336  * The device type associated with the configuration.
3337  *
3338  * Must be set for AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX and
3339  * AV_CODEC_HW_CONFIG_METHOD_HW_FRAMES_CTX, otherwise unused.
3340  */
3342 } AVCodecHWConfig;
3343 
3344 typedef struct AVCodecDefault AVCodecDefault;
3345 
3346 struct AVSubtitle;
3347 
3348 /**
3349  * AVCodec.
3350  */
3351 typedef struct AVCodec {
3352  /**
3353  * Name of the codec implementation.
3354  * The name is globally unique among encoders and among decoders (but an
3355  * encoder and a decoder can share the same name).
3356  * This is the primary way to find a codec from the user perspective.
3357  */
3358  const char *name;
3359  /**
3360  * Descriptive name for the codec, meant to be more human readable than name.
3361  * You should use the NULL_IF_CONFIG_SMALL() macro to define it.
3362  */
3363  const char *long_name;
3366  /**
3367  * Codec capabilities.
3368  * see AV_CODEC_CAP_*
3369  */
3371  const AVRational *supported_framerates; ///< array of supported framerates, or NULL if any, array is terminated by {0,0}
3372  const enum AVPixelFormat *pix_fmts; ///< array of supported pixel formats, or NULL if unknown, array is terminated by -1
3373  const int *supported_samplerates; ///< array of supported audio samplerates, or NULL if unknown, array is terminated by 0
3374  const enum AVSampleFormat *sample_fmts; ///< array of supported sample formats, or NULL if unknown, array is terminated by -1
3375  const uint64_t *channel_layouts; ///< array of support channel layouts, or NULL if unknown. array is terminated by 0
3376  uint8_t max_lowres; ///< maximum value for lowres supported by the decoder
3377  const AVClass *priv_class; ///< AVClass for the private context
3378  const AVProfile *profiles; ///< array of recognized profiles, or NULL if unknown, array is terminated by {FF_PROFILE_UNKNOWN}
3379 
3380  /*****************************************************************
3381  * No fields below this line are part of the public API. They
3382  * may not be used outside of libavcodec and can be changed and
3383  * removed at will.
3384  * New public fields should be added right above.
3385  *****************************************************************
3386  */
3388  struct AVCodec *next;
3389  /**
3390  * @name Frame-level threading support functions
3391  * @{
3392  */
3393  /**
3394  * If defined, called on thread contexts when they are created.
3395  * If the codec allocates writable tables in init(), re-allocate them here.
3396  * priv_data will be set to a copy of the original.
3397  */
3399  /**
3400  * Copy necessary context variables from a previous thread context to the current one.
3401  * If not defined, the next thread will start automatically; otherwise, the codec
3402  * must call ff_thread_finish_setup().
3403  *
3404  * dst and src will (rarely) point to the same context, in which case memcpy should be skipped.
3405  */
3407  /** @} */
3408 
3409  /**
3410  * Private codec-specific defaults.
3411  */
3413 
3414  /**
3415  * Initialize codec static data, called from avcodec_register().
3416  */
3417  void (*init_static_data)(struct AVCodec *codec);
3418 
3420  int (*encode_sub)(AVCodecContext *, uint8_t *buf, int buf_size,
3421  const struct AVSubtitle *sub);
3422  /**
3423  * Encode data to an AVPacket.
3424  *
3425  * @param avctx codec context
3426  * @param avpkt output AVPacket (may contain a user-provided buffer)
3427  * @param[in] frame AVFrame containing the raw data to be encoded
3428  * @param[out] got_packet_ptr encoder sets to 0 or 1 to indicate that a
3429  * non-empty packet was returned in avpkt.
3430  * @return 0 on success, negative error code on failure
3431  */
3432  int (*encode2)(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame,
3433  int *got_packet_ptr);
3434  int (*decode)(AVCodecContext *, void *outdata, int *outdata_size, AVPacket *avpkt);
3436  /**
3437  * Encode API with decoupled packet/frame dataflow. The API is the
3438  * same as the avcodec_ prefixed APIs (avcodec_send_frame() etc.), except
3439  * that:
3440  * - never called if the codec is closed or the wrong type,
3441  * - if AV_CODEC_CAP_DELAY is not set, drain frames are never sent,
3442  * - only one drain frame is ever passed down,
3443  */
3446 
3447  /**
3448  * Decode API with decoupled packet/frame dataflow. This function is called
3449  * to get one output frame. It should call ff_decode_get_packet() to obtain
3450  * input data.
3451  */
3453  /**
3454  * Flush buffers.
3455  * Will be called when seeking
3456  */
3458  /**
3459  * Internal codec capabilities.
3460  * See FF_CODEC_CAP_* in internal.h
3461  */
3463 
3464  /**
3465  * Decoding only, a comma-separated list of bitstream filters to apply to
3466  * packets before decoding.
3467  */
3468  const char *bsfs;
3469 
3470  /**
3471  * Array of pointers to hardware configurations supported by the codec,
3472  * or NULL if no hardware supported. The array is terminated by a NULL
3473  * pointer.
3474  *
3475  * The user can only access this field via avcodec_get_hw_config().
3476  */
3478 } AVCodec;
3479 
3480 #if FF_API_CODEC_GET_SET
3482 int av_codec_get_max_lowres(const AVCodec *codec);
3483 #endif
3484 
3485 struct MpegEncContext;
3486 
3487 /**
3488  * Retrieve supported hardware configurations for a codec.
3489  *
3490  * Values of index from zero to some maximum return the indexed configuration
3491  * descriptor; all other values return NULL. If the codec does not support
3492  * any hardware configurations then it will always return NULL.
3493  */
3494 const AVCodecHWConfig *avcodec_get_hw_config(const AVCodec *codec, int index);
3495 
3496 /**
3497  * @defgroup lavc_hwaccel AVHWAccel
3498  *
3499  * @note Nothing in this structure should be accessed by the user. At some
3500  * point in future it will not be externally visible at all.
3501  *
3502  * @{
3503  */
3504 typedef struct AVHWAccel {
3505  /**
3506  * Name of the hardware accelerated codec.
3507  * The name is globally unique among encoders and among decoders (but an
3508  * encoder and a decoder can share the same name).
3509  */
3510  const char *name;
3511 
3512  /**
3513  * Type of codec implemented by the hardware accelerator.
3514  *
3515  * See AVMEDIA_TYPE_xxx
3516  */
3518 
3519  /**
3520  * Codec implemented by the hardware accelerator.
3521  *
3522  * See AV_CODEC_ID_xxx
3523  */
3525 
3526  /**
3527  * Supported pixel format.
3528  *
3529  * Only hardware accelerated formats are supported here.
3530  */
3532 
3533  /**
3534  * Hardware accelerated codec capabilities.
3535  * see AV_HWACCEL_CODEC_CAP_*
3536  */
3538 
3539  /*****************************************************************
3540  * No fields below this line are part of the public API. They
3541  * may not be used outside of libavcodec and can be changed and
3542  * removed at will.
3543  * New public fields should be added right above.
3544  *****************************************************************
3545  */
3546 
3547  /**
3548  * Allocate a custom buffer
3549  */
3551 
3552  /**
3553  * Called at the beginning of each frame or field picture.
3554  *
3555  * Meaningful frame information (codec specific) is guaranteed to
3556  * be parsed at this point. This function is mandatory.
3557  *
3558  * Note that buf can be NULL along with buf_size set to 0.
3559  * Otherwise, this means the whole frame is available at this point.
3560  *
3561  * @param avctx the codec context
3562  * @param buf the frame data buffer base
3563  * @param buf_size the size of the frame in bytes
3564  * @return zero if successful, a negative value otherwise
3565  */
3566  int (*start_frame)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
3567 
3568  /**
3569  * Callback for parameter data (SPS/PPS/VPS etc).
3570  *
3571  * Useful for hardware decoders which keep persistent state about the
3572  * video parameters, and need to receive any changes to update that state.
3573  *
3574  * @param avctx the codec context
3575  * @param type the nal unit type
3576  * @param buf the nal unit data buffer
3577  * @param buf_size the size of the nal unit in bytes
3578  * @return zero if successful, a negative value otherwise
3579  */
3580  int (*decode_params)(AVCodecContext *avctx, int type, const uint8_t *buf, uint32_t buf_size);
3581 
3582  /**
3583  * Callback for each slice.
3584  *
3585  * Meaningful slice information (codec specific) is guaranteed to
3586  * be parsed at this point. This function is mandatory.
3587  * The only exception is XvMC, that works on MB level.
3588  *
3589  * @param avctx the codec context
3590  * @param buf the slice data buffer base
3591  * @param buf_size the size of the slice in bytes
3592  * @return zero if successful, a negative value otherwise
3593  */
3594  int (*decode_slice)(AVCodecContext *avctx, const uint8_t *buf, uint32_t buf_size);
3595 
3596  /**
3597  * Called at the end of each frame or field picture.
3598  *
3599  * The whole picture is parsed at this point and can now be sent
3600  * to the hardware accelerator. This function is mandatory.
3601  *
3602  * @param avctx the codec context
3603  * @return zero if successful, a negative value otherwise
3604  */
3606 
3607  /**
3608  * Size of per-frame hardware accelerator private data.
3609  *
3610  * Private data is allocated with av_mallocz() before
3611  * AVCodecContext.get_buffer() and deallocated after
3612  * AVCodecContext.release_buffer().
3613  */
3615 
3616  /**
3617  * Called for every Macroblock in a slice.
3618  *
3619  * XvMC uses it to replace the ff_mpv_reconstruct_mb().
3620  * Instead of decoding to raw picture, MB parameters are
3621  * stored in an array provided by the video driver.
3622  *
3623  * @param s the mpeg context
3624  */
3626 
3627  /**
3628  * Initialize the hwaccel private data.
3629  *
3630  * This will be called from ff_get_format(), after hwaccel and
3631  * hwaccel_context are set and the hwaccel private data in AVCodecInternal
3632  * is allocated.
3633  */
3635 
3636  /**
3637  * Uninitialize the hwaccel private data.
3638  *
3639  * This will be called from get_format() or avcodec_close(), after hwaccel
3640  * and hwaccel_context are already uninitialized.
3641  */
3643 
3644  /**
3645  * Size of the private data to allocate in
3646  * AVCodecInternal.hwaccel_priv_data.
3647  */
3649 
3650  /**
3651  * Internal hwaccel capabilities.
3652  */
3654 
3655  /**
3656  * Fill the given hw_frames context with current codec parameters. Called
3657  * from get_format. Refer to avcodec_get_hw_frames_parameters() for
3658  * details.
3659  *
3660  * This CAN be called before AVHWAccel.init is called, and you must assume
3661  * that avctx->hwaccel_priv_data is invalid.
3662  */
3664 } AVHWAccel;
3665 
3666 /**
3667  * HWAccel is experimental and is thus avoided in favor of non experimental
3668  * codecs
3669  */
3670 #define AV_HWACCEL_CODEC_CAP_EXPERIMENTAL 0x0200
3671 
3672 /**
3673  * Hardware acceleration should be used for decoding even if the codec level
3674  * used is unknown or higher than the maximum supported level reported by the
3675  * hardware driver.
3676  *
3677  * It's generally a good idea to pass this flag unless you have a specific
3678  * reason not to, as hardware tends to under-report supported levels.
3679  */
3680 #define AV_HWACCEL_FLAG_IGNORE_LEVEL (1 << 0)
3681 
3682 /**
3683  * Hardware acceleration can output YUV pixel formats with a different chroma
3684  * sampling than 4:2:0 and/or other than 8 bits per component.
3685  */
3686 #define AV_HWACCEL_FLAG_ALLOW_HIGH_DEPTH (1 << 1)
3687 
3688 /**
3689  * Hardware acceleration should still be attempted for decoding when the
3690  * codec profile does not match the reported capabilities of the hardware.
3691  *
3692  * For example, this can be used to try to decode baseline profile H.264
3693  * streams in hardware - it will often succeed, because many streams marked
3694  * as baseline profile actually conform to constrained baseline profile.
3695  *
3696  * @warning If the stream is actually not supported then the behaviour is
3697  * undefined, and may include returning entirely incorrect output
3698  * while indicating success.
3699  */
3700 #define AV_HWACCEL_FLAG_ALLOW_PROFILE_MISMATCH (1 << 2)
3701 
3702 /**
3703  * @}
3704  */
3705 
3706 #if FF_API_AVPICTURE
3707 /**
3708  * @defgroup lavc_picture AVPicture
3709  *
3710  * Functions for working with AVPicture
3711  * @{
3712  */
3713 
3714 /**
3715  * Picture data structure.
3716  *
3717  * Up to four components can be stored into it, the last component is
3718  * alpha.
3719  * @deprecated use AVFrame or imgutils functions instead
3720  */
3721 typedef struct AVPicture {
3723  uint8_t *data[AV_NUM_DATA_POINTERS]; ///< pointers to the image data planes
3725  int linesize[AV_NUM_DATA_POINTERS]; ///< number of bytes per line
3726 } AVPicture;
3727 
3728 /**
3729  * @}
3730  */
3731 #endif
3732 
3735 
3736  SUBTITLE_BITMAP, ///< A bitmap, pict will be set
3737 
3738  /**
3739  * Plain text, the text field must be set by the decoder and is
3740  * authoritative. ass and pict fields may contain approximations.
3741  */
3743 
3744  /**
3745  * Formatted text, the ass field must be set by the decoder and is
3746  * authoritative. pict and text fields may contain approximations.
3747  */
3749 };
3750 
3751 #define AV_SUBTITLE_FLAG_FORCED 0x00000001
3752 
3753 typedef struct AVSubtitleRect {
3754  int x; ///< top left corner of pict, undefined when pict is not set
3755  int y; ///< top left corner of pict, undefined when pict is not set
3756  int w; ///< width of pict, undefined when pict is not set
3757  int h; ///< height of pict, undefined when pict is not set
3758  int nb_colors; ///< number of colors in pict, undefined when pict is not set
3759 
3760 #if FF_API_AVPICTURE
3761  /**
3762  * @deprecated unused
3763  */
3766 #endif
3767  /**
3768  * data+linesize for the bitmap of this subtitle.
3769  * Can be set for text/ass as well once they are rendered.
3770  */
3772  int linesize[4];
3773 
3775 
3776  char *text; ///< 0 terminated plain UTF-8 text
3777 
3778  /**
3779  * 0 terminated ASS/SSA compatible event line.
3780  * The presentation of this is unaffected by the other values in this
3781  * struct.
3782  */
3783  char *ass;
3784 
3785  int flags;
3786 } AVSubtitleRect;
3787 
3788 typedef struct AVSubtitle {
3789  uint16_t format; /* 0 = graphics */
3790  uint32_t start_display_time; /* relative to packet pts, in ms */
3791  uint32_t end_display_time; /* relative to packet pts, in ms */
3792  unsigned num_rects;
3794  int64_t pts; ///< Same as packet pts, in AV_TIME_BASE
3795 } AVSubtitle;
3796 
3797 /**
3798  * This struct describes the properties of an encoded stream.
3799  *
3800  * sizeof(AVCodecParameters) is not a part of the public ABI, this struct must
3801  * be allocated with avcodec_parameters_alloc() and freed with
3802  * avcodec_parameters_free().
3803  */
3804 typedef struct AVCodecParameters {
3805  /**
3806  * General type of the encoded data.
3807  */
3809  /**
3810  * Specific type of the encoded data (the codec used).
3811  */
3813  /**
3814  * Additional information about the codec (corresponds to the AVI FOURCC).
3815  */
3816  uint32_t codec_tag;
3817 
3818  /**
3819  * Extra binary data needed for initializing the decoder, codec-dependent.
3820  *
3821  * Must be allocated with av_malloc() and will be freed by
3822  * avcodec_parameters_free(). The allocated size of extradata must be at
3823  * least extradata_size + AV_INPUT_BUFFER_PADDING_SIZE, with the padding
3824  * bytes zeroed.
3825  */
3827  /**
3828  * Size of the extradata content in bytes.
3829  */
3831 
3832  /**
3833  * - video: the pixel format, the value corresponds to enum AVPixelFormat.
3834  * - audio: the sample format, the value corresponds to enum AVSampleFormat.
3835  */
3836  int format;
3837 
3838  /**
3839  * The average bitrate of the encoded data (in bits per second).
3840  */
3841  int64_t bit_rate;
3842 
3843  /**
3844  * The number of bits per sample in the codedwords.
3845  *
3846  * This is basically the bitrate per sample. It is mandatory for a bunch of
3847  * formats to actually decode them. It's the number of bits for one sample in
3848  * the actual coded bitstream.
3849  *
3850  * This could be for example 4 for ADPCM
3851  * For PCM formats this matches bits_per_raw_sample
3852  * Can be 0
3853  */
3855 
3856  /**
3857  * This is the number of valid bits in each output sample. If the
3858  * sample format has more bits, the least significant bits are additional
3859  * padding bits, which are always 0. Use right shifts to reduce the sample
3860  * to its actual size. For example, audio formats with 24 bit samples will
3861  * have bits_per_raw_sample set to 24, and format set to AV_SAMPLE_FMT_S32.
3862  * To get the original sample use "(int32_t)sample >> 8"."
3863  *
3864  * For ADPCM this might be 12 or 16 or similar
3865  * Can be 0
3866  */
3868 
3869  /**
3870  * Codec-specific bitstream restrictions that the stream conforms to.
3871  */
3872  int profile;
3873  int level;
3874 
3875  /**
3876  * Video only. The dimensions of the video frame in pixels.
3877  */
3878  int width;
3879  int height;
3880 
3881  /**
3882  * Video only. The aspect ratio (width / height) which a single pixel
3883  * should have when displayed.
3884  *
3885  * When the aspect ratio is unknown / undefined, the numerator should be
3886  * set to 0 (the denominator may have any value).
3887  */
3889 
3890  /**
3891  * Video only. The order of the fields in interlaced video.
3892  */
3894 
3895  /**
3896  * Video only. Additional colorspace characteristics.
3897  */
3903 
3904  /**
3905  * Video only. Number of delayed frames.
3906  */
3908 
3909  /**
3910  * Audio only. The channel layout bitmask. May be 0 if the channel layout is
3911  * unknown or unspecified, otherwise the number of bits set must be equal to
3912  * the channels field.
3913  */
3914  uint64_t channel_layout;
3915  /**
3916  * Audio only. The number of audio channels.
3917  */
3919  /**
3920  * Audio only. The number of audio samples per second.
3921  */
3923  /**
3924  * Audio only. The number of bytes per coded audio frame, required by some
3925  * formats.
3926  *
3927  * Corresponds to nBlockAlign in WAVEFORMATEX.
3928  */
3930  /**
3931  * Audio only. Audio frame size, if known. Required by some formats to be static.
3932  */
3934 
3935  /**
3936  * Audio only. The amount of padding (in samples) inserted by the encoder at
3937  * the beginning of the audio. I.e. this number of leading decoded samples
3938  * must be discarded by the caller to get the original audio without leading
3939  * padding.
3940  */
3942  /**
3943  * Audio only. The amount of padding (in samples) appended by the encoder to
3944  * the end of the audio. I.e. this number of decoded samples must be
3945  * discarded by the caller from the end of the stream to get the original
3946  * audio without any trailing padding.
3947  */
3949  /**
3950  * Audio only. Number of samples to skip after a discontinuity.
3951  */
3954 
3955 /**
3956  * If c is NULL, returns the first registered codec,
3957  * if c is non-NULL, returns the next registered codec after c,
3958  * or NULL if c is the last one.
3959  */
3960 AVCodec *av_codec_next(const AVCodec *c);
3961 
3962 /**
3963  * Return the LIBAVCODEC_VERSION_INT constant.
3964  */
3965 unsigned avcodec_version(void);
3966 
3967 /**
3968  * Return the libavcodec build-time configuration.
3969  */
3970 const char *avcodec_configuration(void);
3971 
3972 /**
3973  * Return the libavcodec license.
3974  */
3975 const char *avcodec_license(void);
3976 
3977 /**
3978  * Register the codec codec and initialize libavcodec.
3979  *
3980  * @warning either this function or avcodec_register_all() must be called
3981  * before any other libavcodec functions.
3982  *
3983  * @see avcodec_register_all()
3984  */
3985 void avcodec_register(AVCodec *codec);
3986 
3987 /**
3988  * Register all the codecs, parsers and bitstream filters which were enabled at
3989  * configuration time. If you do not call this function you can select exactly
3990  * which formats you want to support, by using the individual registration
3991  * functions.
3992  *
3993  * @see avcodec_register
3994  * @see av_register_codec_parser
3995  * @see av_register_bitstream_filter
3996  */
3997 void avcodec_register_all(void);
3998 
3999 /**
4000  * Allocate an AVCodecContext and set its fields to default values. The
4001  * resulting struct should be freed with avcodec_free_context().
4002  *
4003  * @param codec if non-NULL, allocate private data and initialize defaults
4004  * for the given codec. It is illegal to then call avcodec_open2()
4005  * with a different codec.
4006  * If NULL, then the codec-specific defaults won't be initialized,
4007  * which may result in suboptimal default settings (this is
4008  * important mainly for encoders, e.g. libx264).
4009  *
4010  * @return An AVCodecContext filled with default values or NULL on failure.
4011  */
4013 
4014 /**
4015  * Free the codec context and everything associated with it and write NULL to
4016  * the provided pointer.
4017  */
4018 void avcodec_free_context(AVCodecContext **avctx);
4019 
4020 #if FF_API_GET_CONTEXT_DEFAULTS
4021 /**
4022  * @deprecated This function should not be used, as closing and opening a codec
4023  * context multiple time is not supported. A new codec context should be
4024  * allocated for each new use.
4025  */
4027 #endif
4028 
4029 /**
4030  * Get the AVClass for AVCodecContext. It can be used in combination with
4031  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
4032  *
4033  * @see av_opt_find().
4034  */
4035 const AVClass *avcodec_get_class(void);
4036 
4037 #if FF_API_COPY_CONTEXT
4038 /**
4039  * Get the AVClass for AVFrame. It can be used in combination with
4040  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
4041  *
4042  * @see av_opt_find().
4043  */
4044 const AVClass *avcodec_get_frame_class(void);
4045 
4046 /**
4047  * Get the AVClass for AVSubtitleRect. It can be used in combination with
4048  * AV_OPT_SEARCH_FAKE_OBJ for examining options.
4049  *
4050  * @see av_opt_find().
4051  */
4053 
4054 /**
4055  * Copy the settings of the source AVCodecContext into the destination
4056  * AVCodecContext. The resulting destination codec context will be
4057  * unopened, i.e. you are required to call avcodec_open2() before you
4058  * can use this AVCodecContext to decode/encode video/audio data.
4059  *
4060  * @param dest target codec context, should be initialized with
4061  * avcodec_alloc_context3(NULL), but otherwise uninitialized
4062  * @param src source codec context
4063  * @return AVERROR() on error (e.g. memory allocation error), 0 on success
4064  *
4065  * @deprecated The semantics of this function are ill-defined and it should not
4066  * be used. If you need to transfer the stream parameters from one codec context
4067  * to another, use an intermediate AVCodecParameters instance and the
4068  * avcodec_parameters_from_context() / avcodec_parameters_to_context()
4069  * functions.
4070  */
4073 #endif
4074 
4075 /**
4076  * Allocate a new AVCodecParameters and set its fields to default values
4077  * (unknown/invalid/0). The returned struct must be freed with
4078  * avcodec_parameters_free().
4079  */
4081 
4082 /**
4083  * Free an AVCodecParameters instance and everything associated with it and
4084  * write NULL to the supplied pointer.
4085  */
4087 
4088 /**
4089  * Copy the contents of src to dst. Any allocated fields in dst are freed and
4090  * replaced with newly allocated duplicates of the corresponding fields in src.
4091  *
4092  * @return >= 0 on success, a negative AVERROR code on failure.
4093  */
4095 
4096 /**
4097  * Fill the parameters struct based on the values from the supplied codec
4098  * context. Any allocated fields in par are freed and replaced with duplicates
4099  * of the corresponding fields in codec.
4100  *
4101  * @return >= 0 on success, a negative AVERROR code on failure
4102  */
4104  const AVCodecContext *codec);
4105 
4106 /**
4107  * Fill the codec context based on the values from the supplied codec
4108  * parameters. Any allocated fields in codec that have a corresponding field in
4109  * par are freed and replaced with duplicates of the corresponding field in par.
4110  * Fields in codec that do not have a counterpart in par are not touched.
4111  *
4112  * @return >= 0 on success, a negative AVERROR code on failure.
4113  */
4115  const AVCodecParameters *par);
4116 
4117 /**
4118  * Initialize the AVCodecContext to use the given AVCodec. Prior to using this
4119  * function the context has to be allocated with avcodec_alloc_context3().
4120  *
4121  * The functions avcodec_find_decoder_by_name(), avcodec_find_encoder_by_name(),
4122  * avcodec_find_decoder() and avcodec_find_encoder() provide an easy way for
4123  * retrieving a codec.
4124  *
4125  * @warning This function is not thread safe!
4126  *
4127  * @note Always call this function before using decoding routines (such as
4128  * @ref avcodec_receive_frame()).
4129  *
4130  * @code
4131  * avcodec_register_all();
4132  * av_dict_set(&opts, "b", "2.5M", 0);
4133  * codec = avcodec_find_decoder(AV_CODEC_ID_H264);
4134  * if (!codec)
4135  * exit(1);
4136  *
4137  * context = avcodec_alloc_context3(codec);
4138  *
4139  * if (avcodec_open2(context, codec, opts) < 0)
4140  * exit(1);
4141  * @endcode
4142  *
4143  * @param avctx The context to initialize.
4144  * @param codec The codec to open this context for. If a non-NULL codec has been
4145  * previously passed to avcodec_alloc_context3() or
4146  * for this context, then this parameter MUST be either NULL or
4147  * equal to the previously passed codec.
4148  * @param options A dictionary filled with AVCodecContext and codec-private options.
4149  * On return this object will be filled with options that were not found.
4150  *
4151  * @return zero on success, a negative value on error
4152  * @see avcodec_alloc_context3(), avcodec_find_decoder(), avcodec_find_encoder(),
4153  * av_dict_set(), av_opt_find().
4154  */
4155 int avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options);
4156 
4157 /**
4158  * Close a given AVCodecContext and free all the data associated with it
4159  * (but not the AVCodecContext itself).
4160  *
4161  * Calling this function on an AVCodecContext that hasn't been opened will free
4162  * the codec-specific data allocated in avcodec_alloc_context3() with a non-NULL
4163  * codec. Subsequent calls will do nothing.
4164  *
4165  * @note Do not use this function. Use avcodec_free_context() to destroy a
4166  * codec context (either open or closed). Opening and closing a codec context
4167  * multiple times is not supported anymore -- use multiple codec contexts
4168  * instead.
4169  */
4170 int avcodec_close(AVCodecContext *avctx);
4171 
4172 /**
4173  * Free all allocated data in the given subtitle struct.
4174  *
4175  * @param sub AVSubtitle to free.
4176  */
4177 void avsubtitle_free(AVSubtitle *sub);
4178 
4179 /**
4180  * @}
4181  */
4182 
4183 /**
4184  * @addtogroup lavc_packet
4185  * @{
4186  */
4187 
4188 /**
4189  * Allocate an AVPacket and set its fields to default values. The resulting
4190  * struct must be freed using av_packet_free().
4191  *
4192  * @return An AVPacket filled with default values or NULL on failure.
4193  *
4194  * @note this only allocates the AVPacket itself, not the data buffers. Those
4195  * must be allocated through other means such as av_new_packet.
4196  *
4197  * @see av_new_packet
4198  */
4199 AVPacket *av_packet_alloc(void);
4200 
4201 /**
4202  * Create a new packet that references the same data as src.
4203  *
4204  * This is a shortcut for av_packet_alloc()+av_packet_ref().
4205  *
4206  * @return newly created AVPacket on success, NULL on error.
4207  *
4208  * @see av_packet_alloc
4209  * @see av_packet_ref
4210  */
4212 
4213 /**
4214  * Free the packet, if the packet is reference counted, it will be
4215  * unreferenced first.
4216  *
4217  * @param pkt packet to be freed. The pointer will be set to NULL.
4218  * @note passing NULL is a no-op.
4219  */
4220 void av_packet_free(AVPacket **pkt);
4221 
4222 /**
4223  * Initialize optional fields of a packet with default values.
4224  *
4225  * Note, this does not touch the data and size members, which have to be
4226  * initialized separately.
4227  *
4228  * @param pkt packet
4229  */
4230 void av_init_packet(AVPacket *pkt);
4231 
4232 /**
4233  * Allocate the payload of a packet and initialize its fields with
4234  * default values.
4235  *
4236  * @param pkt packet
4237  * @param size wanted payload size
4238  * @return 0 if OK, AVERROR_xxx otherwise
4239  */
4240 int av_new_packet(AVPacket *pkt, int size);
4241 
4242 /**
4243  * Reduce packet size, correctly zeroing padding
4244  *
4245  * @param pkt packet
4246  * @param size new size
4247  */
4248 void av_shrink_packet(AVPacket *pkt, int size);
4249 
4250 /**
4251  * Increase packet size, correctly zeroing padding
4252  *
4253  * @param pkt packet
4254  * @param grow_by number of bytes by which to increase the size of the packet
4255  */
4256 int av_grow_packet(AVPacket *pkt, int grow_by);
4257 
4258 /**
4259  * Initialize a reference-counted packet from av_malloc()ed data.
4260  *
4261  * @param pkt packet to be initialized. This function will set the data, size,
4262  * buf and destruct fields, all others are left untouched.
4263  * @param data Data allocated by av_malloc() to be used as packet data. If this
4264  * function returns successfully, the data is owned by the underlying AVBuffer.
4265  * The caller may not access the data through other means.
4266  * @param size size of data in bytes, without the padding. I.e. the full buffer
4267  * size is assumed to be size + AV_INPUT_BUFFER_PADDING_SIZE.
4268  *
4269  * @return 0 on success, a negative AVERROR on error
4270  */
4272 
4273 #if FF_API_AVPACKET_OLD_API
4274 /**
4275  * @warning This is a hack - the packet memory allocation stuff is broken. The
4276  * packet is allocated if it was not really allocated.
4277  *
4278  * @deprecated Use av_packet_ref
4279  */
4281 int av_dup_packet(AVPacket *pkt);
4282 /**
4283  * Copy packet, including contents
4284  *
4285  * @return 0 on success, negative AVERROR on fail
4286  *
4287  * @deprecated Use av_packet_ref
4288  */
4290 int av_copy_packet(AVPacket *dst, const AVPacket *src);
4291 
4292 /**
4293  * Copy packet side data
4294  *
4295  * @return 0 on success, negative AVERROR on fail
4296  *
4297  * @deprecated Use av_packet_copy_props
4298  */
4300 int av_copy_packet_side_data(AVPacket *dst, const AVPacket *src);
4301 
4302 /**
4303  * Free a packet.
4304  *
4305  * @deprecated Use av_packet_unref
4306  *
4307  * @param pkt packet to free
4308  */
4310 void av_free_packet(AVPacket *pkt);
4311 #endif
4312 /**
4313  * Allocate new information of a packet.
4314  *
4315  * @param pkt packet
4316  * @param type side information type
4317  * @param size side information size
4318  * @return pointer to fresh allocated data or NULL otherwise
4319  */
4321  int size);
4322 
4323 /**
4324  * Wrap an existing array as a packet side data.
4325  *
4326  * @param pkt packet
4327  * @param type side information type
4328  * @param data the side data array. It must be allocated with the av_malloc()
4329  * family of functions. The ownership of the data is transferred to
4330  * pkt.
4331  * @param size side information size
4332  * @return a non-negative number on success, a negative AVERROR code on
4333  * failure. On failure, the packet is unchanged and the data remains
4334  * owned by the caller.
4335  */
4337  uint8_t *data, size_t size);
4338 
4339 /**
4340  * Shrink the already allocated side data buffer
4341  *
4342  * @param pkt packet
4343  * @param type side information type
4344  * @param size new side information size
4345  * @return 0 on success, < 0 on failure
4346  */
4348  int size);
4349 
4350 /**
4351  * Get side information from packet.
4352  *
4353  * @param pkt packet
4354  * @param type desired side information type
4355  * @param size pointer for side information size to store (optional)
4356  * @return pointer to data if present or NULL otherwise
4357  */
4359  int *size);
4360 
4361 #if FF_API_MERGE_SD_API
4364 
4367 #endif
4368 
4370 
4371 /**
4372  * Pack a dictionary for use in side_data.
4373  *
4374  * @param dict The dictionary to pack.
4375  * @param size pointer to store the size of the returned data
4376  * @return pointer to data if successful, NULL otherwise
4377  */
4379 /**
4380  * Unpack a dictionary from side_data.
4381  *
4382  * @param data data from side_data
4383  * @param size size of the data
4384  * @param dict the metadata storage dictionary
4385  * @return 0 on success, < 0 on failure
4386  */
4387 int av_packet_unpack_dictionary(const uint8_t *data, int size, AVDictionary **dict);
4388 
4389 
4390 /**
4391  * Convenience function to free all the side data stored.
4392  * All the other fields stay untouched.
4393  *
4394  * @param pkt packet
4395  */
4397 
4398 /**
4399  * Setup a new reference to the data described by a given packet
4400  *
4401  * If src is reference-counted, setup dst as a new reference to the
4402  * buffer in src. Otherwise allocate a new buffer in dst and copy the
4403  * data from src into it.
4404  *
4405  * All the other fields are copied from src.
4406  *
4407  * @see av_packet_unref
4408  *
4409  * @param dst Destination packet
4410  * @param src Source packet
4411  *
4412  * @return 0 on success, a negative AVERROR on error.
4413  */
4414 int av_packet_ref(AVPacket *dst, const AVPacket *src);
4415 
4416 /**
4417  * Wipe the packet.
4418  *
4419  * Unreference the buffer referenced by the packet and reset the
4420  * remaining packet fields to their default values.
4421  *
4422  * @param pkt The packet to be unreferenced.
4423  */
4425 
4426 /**
4427  * Move every field in src to dst and reset src.
4428  *
4429  * @see av_packet_unref
4430  *
4431  * @param src Source packet, will be reset
4432  * @param dst Destination packet
4433  */
4435 
4436 /**
4437  * Copy only "properties" fields from src to dst.
4438  *
4439  * Properties for the purpose of this function are all the fields
4440  * beside those related to the packet data (buf, data, size)
4441  *
4442  * @param dst Destination packet
4443  * @param src Source packet
4444  *
4445  * @return 0 on success AVERROR on failure.
4446  */
4447 int av_packet_copy_props(AVPacket *dst, const AVPacket *src);
4448 
4449 /**
4450  * Convert valid timing fields (timestamps / durations) in a packet from one
4451  * timebase to another. Timestamps with unknown values (AV_NOPTS_VALUE) will be
4452  * ignored.
4453  *
4454  * @param pkt packet on which the conversion will be performed
4455  * @param tb_src source timebase, in which the timing fields in pkt are
4456  * expressed
4457  * @param tb_dst destination timebase, to which the timing fields will be
4458  * converted
4459  */
4460 void av_packet_rescale_ts(AVPacket *pkt, AVRational tb_src, AVRational tb_dst);
4461 
4462 /**
4463  * @}
4464  */
4465 
4466 /**
4467  * @addtogroup lavc_decoding
4468  * @{
4469  */
4470 
4471 /**
4472  * Find a registered decoder with a matching codec ID.
4473  *
4474  * @param id AVCodecID of the requested decoder
4475  * @return A decoder if one was found, NULL otherwise.
4476  */
4478 
4479 /**
4480  * Find a registered decoder with the specified name.
4481  *
4482  * @param name name of the requested decoder
4483  * @return A decoder if one was found, NULL otherwise.
4484  */
4486 
4487 /**
4488  * The default callback for AVCodecContext.get_buffer2(). It is made public so
4489  * it can be called by custom get_buffer2() implementations for decoders without
4490  * AV_CODEC_CAP_DR1 set.
4491  */
4493 
4494 /**
4495  * Modify width and height values so that they will result in a memory
4496  * buffer that is acceptable for the codec if you do not use any horizontal
4497  * padding.
4498  *
4499  * May only be used if a codec with AV_CODEC_CAP_DR1 has been opened.
4500  */
4502 
4503 /**
4504  * Modify width and height values so that they will result in a memory
4505  * buffer that is acceptable for the codec if you also ensure that all
4506  * line sizes are a multiple of the respective linesize_align[i].
4507  *
4508  * May only be used if a codec with AV_CODEC_CAP_DR1 has been opened.
4509  */
4511  int linesize_align[AV_NUM_DATA_POINTERS]);
4512 
4513 /**
4514  * Converts AVChromaLocation to swscale x/y chroma position.
4515  *
4516  * The positions represent the chroma (0,0) position in a coordinates system
4517  * with luma (0,0) representing the origin and luma(1,1) representing 256,256
4518  *
4519  * @param xpos horizontal chroma sample position
4520  * @param ypos vertical chroma sample position
4521  */
4522 int avcodec_enum_to_chroma_pos(int *xpos, int *ypos, enum AVChromaLocation pos);
4523 
4524 /**
4525  * Converts swscale x/y chroma position to AVChromaLocation.
4526  *
4527  * The positions represent the chroma (0,0) position in a coordinates system
4528  * with luma (0,0) representing the origin and luma(1,1) representing 256,256
4529  *
4530  * @param xpos horizontal chroma sample position
4531  * @param ypos vertical chroma sample position
4532  */
4533 enum AVChromaLocation avcodec_chroma_pos_to_enum(int xpos, int ypos);
4534 
4535 /**
4536  * Decode the audio frame of size avpkt->size from avpkt->data into frame.
4537  *
4538  * Some decoders may support multiple frames in a single AVPacket. Such
4539  * decoders would then just decode the first frame and the return value would be
4540  * less than the packet size. In this case, avcodec_decode_audio4 has to be
4541  * called again with an AVPacket containing the remaining data in order to
4542  * decode the second frame, etc... Even if no frames are returned, the packet
4543  * needs to be fed to the decoder with remaining data until it is completely
4544  * consumed or an error occurs.
4545  *
4546  * Some decoders (those marked with AV_CODEC_CAP_DELAY) have a delay between input
4547  * and output. This means that for some packets they will not immediately
4548  * produce decoded output and need to be flushed at the end of decoding to get
4549  * all the decoded data. Flushing is done by calling this function with packets
4550  * with avpkt->data set to NULL and avpkt->size set to 0 until it stops
4551  * returning samples. It is safe to flush even those decoders that are not
4552  * marked with AV_CODEC_CAP_DELAY, then no samples will be returned.
4553  *
4554  * @warning The input buffer, avpkt->data must be AV_INPUT_BUFFER_PADDING_SIZE
4555  * larger than the actual read bytes because some optimized bitstream
4556  * readers read 32 or 64 bits at once and could read over the end.
4557  *
4558  * @note The AVCodecContext MUST have been opened with @ref avcodec_open2()
4559  * before packets may be fed to the decoder.
4560  *
4561  * @param avctx the codec context
4562  * @param[out] frame The AVFrame in which to store decoded audio samples.
4563  * The decoder will allocate a buffer for the decoded frame by
4564  * calling the AVCodecContext.get_buffer2() callback.
4565  * When AVCodecContext.refcounted_frames is set to 1, the frame is
4566  * reference counted and the returned reference belongs to the
4567  * caller. The caller must release the frame using av_frame_unref()
4568  * when the frame is no longer needed. The caller may safely write
4569  * to the frame if av_frame_is_writable() returns 1.
4570  * When AVCodecContext.refcounted_frames is set to 0, the returned
4571  * reference belongs to the decoder and is valid only until the
4572  * next call to this function or until closing or flushing the
4573  * decoder. The caller may not write to it.
4574  * @param[out] got_frame_ptr Zero if no frame could be decoded, otherwise it is
4575  * non-zero. Note that this field being set to zero
4576  * does not mean that an error has occurred. For
4577  * decoders with AV_CODEC_CAP_DELAY set, no given decode
4578  * call is guaranteed to produce a frame.
4579  * @param[in] avpkt The input AVPacket containing the input buffer.
4580  * At least avpkt->data and avpkt->size should be set. Some
4581  * decoders might also require additional fields to be set.
4582  * @return A negative error code is returned if an error occurred during
4583  * decoding, otherwise the number of bytes consumed from the input
4584  * AVPacket is returned.
4585  *
4586 * @deprecated Use avcodec_send_packet() and avcodec_receive_frame().
4587  */
4590  int *got_frame_ptr, const AVPacket *avpkt);
4591 
4592 /**
4593  * Decode the video frame of size avpkt->size from avpkt->data into picture.
4594  * Some decoders may support multiple frames in a single AVPacket, such
4595  * decoders would then just decode the first frame.
4596  *
4597  * @warning The input buffer must be AV_INPUT_BUFFER_PADDING_SIZE larger than
4598  * the actual read bytes because some optimized bitstream readers read 32 or 64
4599  * bits at once and could read over the end.
4600  *
4601  * @warning The end of the input buffer buf should be set to 0 to ensure that
4602  * no overreading happens for damaged MPEG streams.
4603  *
4604  * @note Codecs which have the AV_CODEC_CAP_DELAY capability set have a delay
4605  * between input and output, these need to be fed with avpkt->data=NULL,
4606  * avpkt->size=0 at the end to return the remaining frames.
4607  *
4608  * @note The AVCodecContext MUST have been opened with @ref avcodec_open2()
4609  * before packets may be fed to the decoder.
4610  *
4611  * @param avctx the codec context
4612  * @param[out] picture The AVFrame in which the decoded video frame will be stored.
4613  * Use av_frame_alloc() to get an AVFrame. The codec will
4614  * allocate memory for the actual bitmap by calling the
4615  * AVCodecContext.get_buffer2() callback.
4616  * When AVCodecContext.refcounted_frames is set to 1, the frame is
4617  * reference counted and the returned reference belongs to the
4618  * caller. The caller must release the frame using av_frame_unref()
4619  * when the frame is no longer needed. The caller may safely write
4620  * to the frame if av_frame_is_writable() returns 1.
4621  * When AVCodecContext.refcounted_frames is set to 0, the returned
4622  * reference belongs to the decoder and is valid only until the
4623  * next call to this function or until closing or flushing the
4624  * decoder. The caller may not write to it.
4625  *
4626  * @param[in] avpkt The input AVPacket containing the input buffer.
4627  * You can create such packet with av_init_packet() and by then setting
4628  * data and size, some decoders might in addition need other fields like
4629  * flags&AV_PKT_FLAG_KEY. All decoders are designed to use the least
4630  * fields possible.
4631  * @param[in,out] got_picture_ptr Zero if no frame could be decompressed, otherwise, it is nonzero.
4632  * @return On error a negative value is returned, otherwise the number of bytes
4633  * used or zero if no frame could be decompressed.
4634  *
4635  * @deprecated Use avcodec_send_packet() and avcodec_receive_frame().
4636  */
4638 int avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
4639  int *got_picture_ptr,
4640  const AVPacket *avpkt);
4641 
4642 /**
4643  * Decode a subtitle message.
4644  * Return a negative value on error, otherwise return the number of bytes used.
4645  * If no subtitle could be decompressed, got_sub_ptr is zero.
4646  * Otherwise, the subtitle is stored in *sub.
4647  * Note that AV_CODEC_CAP_DR1 is not available for subtitle codecs. This is for
4648  * simplicity, because the performance difference is expect to be negligible
4649  * and reusing a get_buffer written for video codecs would probably perform badly
4650  * due to a potentially very different allocation pattern.
4651  *
4652  * Some decoders (those marked with AV_CODEC_CAP_DELAY) have a delay between input
4653  * and output. This means that for some packets they will not immediately
4654  * produce decoded output and need to be flushed at the end of decoding to get
4655  * all the decoded data. Flushing is done by calling this function with packets
4656  * with avpkt->data set to NULL and avpkt->size set to 0 until it stops
4657  * returning subtitles. It is safe to flush even those decoders that are not
4658  * marked with AV_CODEC_CAP_DELAY, then no subtitles will be returned.
4659  *
4660  * @note The AVCodecContext MUST have been opened with @ref avcodec_open2()
4661  * before packets may be fed to the decoder.
4662  *
4663  * @param avctx the codec context
4664  * @param[out] sub The Preallocated AVSubtitle in which the decoded subtitle will be stored,
4665  * must be freed with avsubtitle_free if *got_sub_ptr is set.
4666  * @param[in,out] got_sub_ptr Zero if no subtitle could be decompressed, otherwise, it is nonzero.
4667  * @param[in] avpkt The input AVPacket containing the input buffer.
4668  */
4670  int *got_sub_ptr,
4671  AVPacket *avpkt);
4672 
4673 /**
4674  * Supply raw packet data as input to a decoder.
4675  *
4676  * Internally, this call will copy relevant AVCodecContext fields, which can
4677  * influence decoding per-packet, and apply them when the packet is actually
4678  * decoded. (For example AVCodecContext.skip_frame, which might direct the
4679  * decoder to drop the frame contained by the packet sent with this function.)
4680  *
4681  * @warning The input buffer, avpkt->data must be AV_INPUT_BUFFER_PADDING_SIZE
4682  * larger than the actual read bytes because some optimized bitstream
4683  * readers read 32 or 64 bits at once and could read over the end.
4684  *
4685  * @warning Do not mix this API with the legacy API (like avcodec_decode_video2())
4686  * on the same AVCodecContext. It will return unexpected results now
4687  * or in future libavcodec versions.
4688  *
4689  * @note The AVCodecContext MUST have been opened with @ref avcodec_open2()
4690  * before packets may be fed to the decoder.
4691  *
4692  * @param avctx codec context
4693  * @param[in] avpkt The input AVPacket. Usually, this will be a single video
4694  * frame, or several complete audio frames.
4695  * Ownership of the packet remains with the caller, and the
4696  * decoder will not write to the packet. The decoder may create
4697  * a reference to the packet data (or copy it if the packet is
4698  * not reference-counted).
4699  * Unlike with older APIs, the packet is always fully consumed,
4700  * and if it contains multiple frames (e.g. some audio codecs),
4701  * will require you to call avcodec_receive_frame() multiple
4702  * times afterwards before you can send a new packet.
4703  * It can be NULL (or an AVPacket with data set to NULL and
4704  * size set to 0); in this case, it is considered a flush
4705  * packet, which signals the end of the stream. Sending the
4706  * first flush packet will return success. Subsequent ones are
4707  * unnecessary and will return AVERROR_EOF. If the decoder
4708  * still has frames buffered, it will return them after sending
4709  * a flush packet.
4710  *
4711  * @return 0 on success, otherwise negative error code:
4712  * AVERROR(EAGAIN): input is not accepted in the current state - user
4713  * must read output with avcodec_receive_frame() (once
4714  * all output is read, the packet should be resent, and
4715  * the call will not fail with EAGAIN).
4716  * AVERROR_EOF: the decoder has been flushed, and no new packets can
4717  * be sent to it (also returned if more than 1 flush
4718  * packet is sent)
4719  * AVERROR(EINVAL): codec not opened, it is an encoder, or requires flush
4720  * AVERROR(ENOMEM): failed to add packet to internal queue, or similar
4721  * other errors: legitimate decoding errors
4722  */
4723 int avcodec_send_packet(AVCodecContext *avctx, const AVPacket *avpkt);
4724 
4725 /**
4726  * Return decoded output data from a decoder.
4727  *
4728  * @param avctx codec context
4729  * @param frame This will be set to a reference-counted video or audio
4730  * frame (depending on the decoder type) allocated by the
4731  * decoder. Note that the function will always call
4732  * av_frame_unref(frame) before doing anything else.
4733  *
4734  * @return
4735  * 0: success, a frame was returned
4736  * AVERROR(EAGAIN): output is not available in this state - user must try
4737  * to send new input
4738  * AVERROR_EOF: the decoder has been fully flushed, and there will be
4739  * no more output frames
4740  * AVERROR(EINVAL): codec not opened, or it is an encoder
4741  * other negative values: legitimate decoding errors
4742  */
4744 
4745 /**
4746  * Supply a raw video or audio frame to the encoder. Use avcodec_receive_packet()
4747  * to retrieve buffered output packets.
4748  *
4749  * @param avctx codec context
4750  * @param[in] frame AVFrame containing the raw audio or video frame to be encoded.
4751  * Ownership of the frame remains with the caller, and the
4752  * encoder will not write to the frame. The encoder may create
4753  * a reference to the frame data (or copy it if the frame is
4754  * not reference-counted).
4755  * It can be NULL, in which case it is considered a flush
4756  * packet. This signals the end of the stream. If the encoder
4757  * still has packets buffered, it will return them after this
4758  * call. Once flushing mode has been entered, additional flush
4759  * packets are ignored, and sending frames will return
4760  * AVERROR_EOF.
4761  *
4762  * For audio:
4763  * If AV_CODEC_CAP_VARIABLE_FRAME_SIZE is set, then each frame
4764  * can have any number of samples.
4765  * If it is not set, frame->nb_samples must be equal to
4766  * avctx->frame_size for all frames except the last.
4767  * The final frame may be smaller than avctx->frame_size.
4768  * @return 0 on success, otherwise negative error code:
4769  * AVERROR(EAGAIN): input is not accepted in the current state - user
4770  * must read output with avcodec_receive_packet() (once
4771  * all output is read, the packet should be resent, and
4772  * the call will not fail with EAGAIN).
4773  * AVERROR_EOF: the encoder has been flushed, and no new frames can
4774  * be sent to it
4775  * AVERROR(EINVAL): codec not opened, refcounted_frames not set, it is a
4776  * decoder, or requires flush
4777  * AVERROR(ENOMEM): failed to add packet to internal queue, or similar
4778  * other errors: legitimate decoding errors
4779  */
4780 int avcodec_send_frame(AVCodecContext *avctx, const AVFrame *frame);
4781 
4782 /**
4783  * Read encoded data from the encoder.
4784  *
4785  * @param avctx codec context
4786  * @param avpkt This will be set to a reference-counted packet allocated by the
4787  * encoder. Note that the function will always call
4788  * av_frame_unref(frame) before doing anything else.
4789  * @return 0 on success, otherwise negative error code:
4790  * AVERROR(EAGAIN): output is not available in the current state - user
4791  * must try to send input
4792  * AVERROR_EOF: the encoder has been fully flushed, and there will be
4793  * no more output packets
4794  * AVERROR(EINVAL): codec not opened, or it is an encoder
4795  * other errors: legitimate decoding errors
4796  */
4797 int avcodec_receive_packet(AVCodecContext *avctx, AVPacket *avpkt);
4798 
4799 /**
4800  * Create and return a AVHWFramesContext with values adequate for hardware
4801  * decoding. This is meant to get called from the get_format callback, and is
4802  * a helper for preparing a AVHWFramesContext for AVCodecContext.hw_frames_ctx.
4803  * This API is for decoding with certain hardware acceleration modes/APIs only.
4804  *
4805  * The returned AVHWFramesContext is not initialized. The caller must do this
4806  * with av_hwframe_ctx_init().
4807  *
4808  * Calling this function is not a requirement, but makes it simpler to avoid
4809  * codec or hardware API specific details when manually allocating frames.
4810  *
4811  * Alternatively to this, an API user can set AVCodecContext.hw_device_ctx,
4812  * which sets up AVCodecContext.hw_frames_ctx fully automatically, and makes
4813  * it unnecessary to call this function or having to care about
4814  * AVHWFramesContext initialization at all.
4815  *
4816  * There are a number of requirements for calling this function:
4817  *
4818  * - It must be called from get_format with the same avctx parameter that was
4819  * passed to get_format. Calling it outside of get_format is not allowed, and
4820  * can trigger undefined behavior.
4821  * - The function is not always supported (see description of return values).
4822  * Even if this function returns successfully, hwaccel initialization could
4823  * fail later. (The degree to which implementations check whether the stream
4824  * is actually supported varies. Some do this check only after the user's
4825  * get_format callback returns.)
4826  * - The hw_pix_fmt must be one of the choices suggested by get_format. If the
4827  * user decides to use a AVHWFramesContext prepared with this API function,
4828  * the user must return the same hw_pix_fmt from get_format.
4829  * - The device_ref passed to this function must support the given hw_pix_fmt.
4830  * - After calling this API function, it is the user's responsibility to
4831  * initialize the AVHWFramesContext (returned by the out_frames_ref parameter),
4832  * and to set AVCodecContext.hw_frames_ctx to it. If done, this must be done
4833  * before returning from get_format (this is implied by the normal
4834  * AVCodecContext.hw_frames_ctx API rules).
4835  * - The AVHWFramesContext parameters may change every time time get_format is
4836  * called. Also, AVCodecContext.hw_frames_ctx is reset before get_format. So
4837  * you are inherently required to go through this process again on every
4838  * get_format call.
4839  * - It is perfectly possible to call this function without actually using
4840  * the resulting AVHWFramesContext. One use-case might be trying to reuse a
4841  * previously initialized AVHWFramesContext, and calling this API function
4842  * only to test whether the required frame parameters have changed.
4843  * - Fields that use dynamically allocated values of any kind must not be set
4844  * by the user unless setting them is explicitly allowed by the documentation.
4845  * If the user sets AVHWFramesContext.free and AVHWFramesContext.user_opaque,
4846  * the new free callback must call the potentially set previous free callback.
4847  * This API call may set any dynamically allocated fields, including the free
4848  * callback.
4849  *
4850  * The function will set at least the following fields on AVHWFramesContext
4851  * (potentially more, depending on hwaccel API):
4852  *
4853  * - All fields set by av_hwframe_ctx_alloc().
4854  * - Set the format field to hw_pix_fmt.
4855  * - Set the sw_format field to the most suited and most versatile format. (An
4856  * implication is that this will prefer generic formats over opaque formats
4857  * with arbitrary restrictions, if possible.)
4858  * - Set the width/height fields to the coded frame size, rounded up to the
4859  * API-specific minimum alignment.
4860  * - Only _if_ the hwaccel requires a pre-allocated pool: set the initial_pool_size
4861  * field to the number of maximum reference surfaces possible with the codec,
4862  * plus 1 surface for the user to work (meaning the user can safely reference
4863  * at most 1 decoded surface at a time), plus additional buffering introduced
4864  * by frame threading. If the hwaccel does not require pre-allocation, the
4865  * field is left to 0, and the decoder will allocate new surfaces on demand
4866  * during decoding.
4867  * - Possibly AVHWFramesContext.hwctx fields, depending on the underlying
4868  * hardware API.
4869  *
4870  * Essentially, out_frames_ref returns the same as av_hwframe_ctx_alloc(), but
4871  * with basic frame parameters set.
4872  *
4873  * The function is stateless, and does not change the AVCodecContext or the
4874  * device_ref AVHWDeviceContext.
4875  *
4876  * @param avctx The context which is currently calling get_format, and which
4877  * implicitly contains all state needed for filling the returned
4878  * AVHWFramesContext properly.
4879  * @param device_ref A reference to the AVHWDeviceContext describing the device
4880  * which will be used by the hardware decoder.
4881  * @param hw_pix_fmt The hwaccel format you are going to return from get_format.
4882  * @param out_frames_ref On success, set to a reference to an _uninitialized_
4883  * AVHWFramesContext, created from the given device_ref.
4884  * Fields will be set to values required for decoding.
4885  * Not changed if an error is returned.
4886  * @return zero on success, a negative value on error. The following error codes
4887  * have special semantics:
4888  * AVERROR(ENOENT): the decoder does not support this functionality. Setup
4889  * is always manual, or it is a decoder which does not
4890  * support setting AVCodecContext.hw_frames_ctx at all,
4891  * or it is a software format.
4892  * AVERROR(EINVAL): it is known that hardware decoding is not supported for
4893  * this configuration, or the device_ref is not supported
4894  * for the hwaccel referenced by hw_pix_fmt.
4895  */
4897  AVBufferRef *device_ref,
4899  AVBufferRef **out_frames_ref);
4900 
4901 
4902 
4903 /**
4904  * @defgroup lavc_parsing Frame parsing
4905  * @{
4906  */
4907 
4910  AV_PICTURE_STRUCTURE_TOP_FIELD, //< coded as top field
4911  AV_PICTURE_STRUCTURE_BOTTOM_FIELD, //< coded as bottom field
4912  AV_PICTURE_STRUCTURE_FRAME, //< coded as frame
4913 };
4914 
4915 typedef struct AVCodecParserContext {
4916  void *priv_data;
4918  int64_t frame_offset; /* offset of the current frame */
4919  int64_t cur_offset; /* current offset
4920  (incremented by each av_parser_parse()) */
4921  int64_t next_frame_offset; /* offset of the next frame */
4922  /* video info */
4923  int pict_type; /* XXX: Put it back in AVCodecContext. */
4924  /**
4925  * This field is used for proper frame duration computation in lavf.
4926  * It signals, how much longer the frame duration of the current frame
4927  * is compared to normal frame duration.
4928  *
4929  * frame_duration = (1 + repeat_pict) * time_base
4930  *
4931  * It is used by codecs like H.264 to display telecined material.
4932  */
4933  int repeat_pict; /* XXX: Put it back in AVCodecContext. */
4934  int64_t pts; /* pts of the current frame */
4935  int64_t dts; /* dts of the current frame */
4936 
4937  /* private data */
4938  int64_t last_pts;
4939  int64_t last_dts;
4941 
4942 #define AV_PARSER_PTS_NB 4
4947 
4948  int flags;
4949 #define PARSER_FLAG_COMPLETE_FRAMES 0x0001
4950 #define PARSER_FLAG_ONCE 0x0002
4951 /// Set if the parser has a valid file offset
4952 #define PARSER_FLAG_FETCHED_OFFSET 0x0004
4953 #define PARSER_FLAG_USE_CODEC_TS 0x1000
4954 
4955  int64_t offset; ///< byte offset from starting packet start
4957 
4958  /**
4959  * Set by parser to 1 for key frames and 0 for non-key frames.
4960  * It is initialized to -1, so if the parser doesn't set this flag,
4961  * old-style fallback using AV_PICTURE_TYPE_I picture type as key frames
4962  * will be used.
4963  */
4965 
4966 #if FF_API_CONVERGENCE_DURATION
4967  /**
4968  * @deprecated unused
4969  */
4972 #endif
4973 
4974  // Timestamp generation support:
4975  /**
4976  * Synchronization point for start of timestamp generation.
4977  *
4978  * Set to >0 for sync point, 0 for no sync point and <0 for undefined
4979  * (default).
4980  *
4981  * For example, this corresponds to presence of H.264 buffering period
4982  * SEI message.
4983  */
4985 
4986  /**
4987  * Offset of the current timestamp against last timestamp sync point in
4988  * units of AVCodecContext.time_base.
4989  *
4990  * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
4991  * contain a valid timestamp offset.
4992  *
4993  * Note that the timestamp of sync point has usually a nonzero
4994  * dts_ref_dts_delta, which refers to the previous sync point. Offset of
4995  * the next frame after timestamp sync point will be usually 1.
4996  *
4997  * For example, this corresponds to H.264 cpb_removal_delay.
4998  */
5000 
5001  /**
5002  * Presentation delay of current frame in units of AVCodecContext.time_base.
5003  *
5004  * Set to INT_MIN when dts_sync_point unused. Otherwise, it must
5005  * contain valid non-negative timestamp delta (presentation time of a frame
5006  * must not lie in the past).
5007  *
5008  * This delay represents the difference between decoding and presentation
5009  * time of the frame.
5010  *
5011  * For example, this corresponds to H.264 dpb_output_delay.
5012  */
5014 
5015  /**
5016  * Position of the packet in file.
5017  *
5018  * Analogous to cur_frame_pts/dts
5019  */
5021 
5022  /**
5023  * Byte position of currently parsed frame in stream.
5024  */
5025  int64_t pos;
5026 
5027  /**
5028  * Previous frame byte position.
5029  */
5030  int64_t last_pos;
5031 
5032  /**
5033  * Duration of the current frame.
5034  * For audio, this is in units of 1 / AVCodecContext.sample_rate.
5035  * For all other types, this is in units of AVCodecContext.time_base.
5036  */
5038 
5040 
5041  /**
5042  * Indicate whether a picture is coded as a frame, top field or bottom field.
5043  *
5044  * For example, H.264 field_pic_flag equal to 0 corresponds to
5045  * AV_PICTURE_STRUCTURE_FRAME. An H.264 picture with field_pic_flag
5046  * equal to 1 and bottom_field_flag equal to 0 corresponds to
5047  * AV_PICTURE_STRUCTURE_TOP_FIELD.
5048  */
5050 
5051  /**
5052  * Picture number incremented in presentation or output order.
5053  * This field may be reinitialized at the first picture of a new sequence.
5054  *
5055  * For example, this corresponds to H.264 PicOrderCnt.
5056  */
5058 
5059  /**
5060  * Dimensions of the decoded video intended for presentation.
5061  */
5062  int width;
5063  int height;
5064 
5065  /**
5066  * Dimensions of the coded video.
5067  */
5070 
5071  /**
5072  * The format of the coded data, corresponds to enum AVPixelFormat for video
5073  * and for enum AVSampleFormat for audio.
5074  *
5075  * Note that a decoder can have considerable freedom in how exactly it
5076  * decodes the data, so the format reported here might be different from the
5077  * one returned by a decoder.
5078  */
5079  int format;
5081 
5082 typedef struct AVCodecParser {
5083  int codec_ids[5]; /* several codec IDs are permitted */
5086  /* This callback never returns an error, a negative value means that
5087  * the frame start was in a previous packet. */
5089  AVCodecContext *avctx,
5090  const uint8_t **poutbuf, int *poutbuf_size,
5091  const uint8_t *buf, int buf_size);
5093  int (*split)(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
5095 } AVCodecParser;
5096 
5098 
5101 
5102 /**
5103  * Parse a packet.
5104  *
5105  * @param s parser context.
5106  * @param avctx codec context.
5107  * @param poutbuf set to pointer to parsed buffer or NULL if not yet finished.
5108  * @param poutbuf_size set to size of parsed buffer or zero if not yet finished.
5109  * @param buf input buffer.
5110  * @param buf_size buffer size in bytes without the padding. I.e. the full buffer
5111  size is assumed to be buf_size + AV_INPUT_BUFFER_PADDING_SIZE.
5112  To signal EOF, this should be 0 (so that the last frame
5113  can be output).
5114  * @param pts input presentation timestamp.
5115  * @param dts input decoding timestamp.
5116  * @param pos input byte position in stream.
5117  * @return the number of bytes of the input bitstream used.
5118  *
5119  * Example:
5120  * @code
5121  * while(in_len){
5122  * len = av_parser_parse2(myparser, AVCodecContext, &data, &size,
5123  * in_data, in_len,
5124  * pts, dts, pos);
5125  * in_data += len;
5126  * in_len -= len;
5127  *
5128  * if(size)
5129  * decode_frame(data, size);
5130  * }
5131  * @endcode
5132  */
5134  AVCodecContext *avctx,
5135  uint8_t **poutbuf, int *poutbuf_size,
5136  const uint8_t *buf, int buf_size,
5137  int64_t pts, int64_t dts,
5138  int64_t pos);
5139 
5140 /**
5141  * @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
5142  * @deprecated use AVBitStreamFilter
5143  */
5145  AVCodecContext *avctx,
5146  uint8_t **poutbuf, int *poutbuf_size,
5147  const uint8_t *buf, int buf_size, int keyframe);
5149 
5150 /**
5151  * @}
5152  * @}
5153  */
5154 
5155 /**
5156  * @addtogroup lavc_encoding
5157  * @{
5158  */
5159 
5160 /**
5161  * Find a registered encoder with a matching codec ID.
5162  *
5163  * @param id AVCodecID of the requested encoder
5164  * @return An encoder if one was found, NULL otherwise.
5165  */
5167 
5168 /**
5169  * Find a registered encoder with the specified name.
5170  *
5171  * @param name name of the requested encoder
5172  * @return An encoder if one was found, NULL otherwise.
5173  */
5175 
5176 /**
5177  * Encode a frame of audio.
5178  *
5179  * Takes input samples from frame and writes the next output packet, if
5180  * available, to avpkt. The output packet does not necessarily contain data for
5181  * the most recent frame, as encoders can delay, split, and combine input frames
5182  * internally as needed.
5183  *
5184  * @param avctx codec context
5185  * @param avpkt output AVPacket.
5186  * The user can supply an output buffer by setting
5187  * avpkt->data and avpkt->size prior to calling the
5188  * function, but if the size of the user-provided data is not
5189  * large enough, encoding will fail. If avpkt->data and
5190  * avpkt->size are set, avpkt->destruct must also be set. All
5191  * other AVPacket fields will be reset by the encoder using
5192  * av_init_packet(). If avpkt->data is NULL, the encoder will
5193  * allocate it. The encoder will set avpkt->size to the size
5194  * of the output packet.
5195  *
5196  * If this function fails or produces no output, avpkt will be
5197  * freed using av_packet_unref().
5198  * @param[in] frame AVFrame containing the raw audio data to be encoded.
5199  * May be NULL when flushing an encoder that has the
5200  * AV_CODEC_CAP_DELAY capability set.
5201  * If AV_CODEC_CAP_VARIABLE_FRAME_SIZE is set, then each frame
5202  * can have any number of samples.
5203  * If it is not set, frame->nb_samples must be equal to
5204  * avctx->frame_size for all frames except the last.
5205  * The final frame may be smaller than avctx->frame_size.
5206  * @param[out] got_packet_ptr This field is set to 1 by libavcodec if the
5207  * output packet is non-empty, and to 0 if it is
5208  * empty. If the function returns an error, the
5209  * packet can be assumed to be invalid, and the
5210  * value of got_packet_ptr is undefined and should
5211  * not be used.
5212  * @return 0 on success, negative error code on failure
5213  *
5214  * @deprecated use avcodec_send_frame()/avcodec_receive_packet() instead
5215  */
5217 int avcodec_encode_audio2(AVCodecContext *avctx, AVPacket *avpkt,
5218  const AVFrame *frame, int *got_packet_ptr);
5219 
5220 /**
5221  * Encode a frame of video.
5222  *
5223  * Takes input raw video data from frame and writes the next output packet, if
5224  * available, to avpkt. The output packet does not necessarily contain data for
5225  * the most recent frame, as encoders can delay and reorder input frames
5226  * internally as needed.
5227  *
5228  * @param avctx codec context
5229  * @param avpkt output AVPacket.
5230  * The user can supply an output buffer by setting
5231  * avpkt->data and avpkt->size prior to calling the
5232  * function, but if the size of the user-provided data is not
5233  * large enough, encoding will fail. All other AVPacket fields
5234  * will be reset by the encoder using av_init_packet(). If
5235  * avpkt->data is NULL, the encoder will allocate it.
5236  * The encoder will set avpkt->size to the size of the
5237  * output packet. The returned data (if any) belongs to the
5238  * caller, he is responsible for freeing it.
5239  *
5240  * If this function fails or produces no output, avpkt will be
5241  * freed using av_packet_unref().
5242  * @param[in] frame AVFrame containing the raw video data to be encoded.
5243  * May be NULL when flushing an encoder that has the
5244  * AV_CODEC_CAP_DELAY capability set.
5245  * @param[out] got_packet_ptr This field is set to 1 by libavcodec if the
5246  * output packet is non-empty, and to 0 if it is
5247  * empty. If the function returns an error, the
5248  * packet can be assumed to be invalid, and the
5249  * value of got_packet_ptr is undefined and should
5250  * not be used.
5251  * @return 0 on success, negative error code on failure
5252  *
5253  * @deprecated use avcodec_send_frame()/avcodec_receive_packet() instead
5254  */
5256 int avcodec_encode_video2(AVCodecContext *avctx, AVPacket *avpkt,
5257  const AVFrame *frame, int *got_packet_ptr);
5258 
5259 int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
5260  const AVSubtitle *sub);
5261 
5262 
5263 /**
5264  * @}
5265  */
5266 
5267 #if FF_API_AVPICTURE
5268 /**
5269  * @addtogroup lavc_picture
5270  * @{
5271  */
5272 
5273 /**
5274  * @deprecated unused
5275  */
5277 int avpicture_alloc(AVPicture *picture, enum AVPixelFormat pix_fmt, int width, int height);
5278 
5279 /**
5280  * @deprecated unused
5281  */
5283 void avpicture_free(AVPicture *picture);
5284 
5285 /**
5286  * @deprecated use av_image_fill_arrays() instead.
5287  */
5289 int avpicture_fill(AVPicture *picture, const uint8_t *ptr,
5290  enum AVPixelFormat pix_fmt, int width, int height);
5291 
5292 /**
5293  * @deprecated use av_image_copy_to_buffer() instead.
5294  */
5297  int width, int height,
5298  unsigned char *dest, int dest_size);
5299 
5300 /**
5301  * @deprecated use av_image_get_buffer_size() instead.
5302  */
5305 
5306 /**
5307  * @deprecated av_image_copy() instead.
5308  */
5310 void av_picture_copy(AVPicture *dst, const AVPicture *src,
5311  enum AVPixelFormat pix_fmt, int width, int height);
5312 
5313 /**
5314  * @deprecated unused
5315  */
5317 int av_picture_crop(AVPicture *dst, const AVPicture *src,
5318  enum AVPixelFormat pix_fmt, int top_band, int left_band);
5319 
5320 /**
5321  * @deprecated unused
5322  */
5324 int av_picture_pad(AVPicture *dst, const AVPicture *src, int height, int width, enum AVPixelFormat pix_fmt,
5325  int padtop, int padbottom,