FFmpeg
decode.h
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1 /*
2  * generic decoding-related code
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_DECODE_H
22 #define AVCODEC_DECODE_H
23 
24 #include "libavutil/buffer.h"
25 #include "libavutil/frame.h"
26 #include "libavutil/hwcontext.h"
27 
28 #include "avcodec.h"
29 
30 /**
31  * This struct stores per-frame lavc-internal data and is attached to it via
32  * private_ref.
33  */
34 typedef struct FrameDecodeData {
35  /**
36  * The callback to perform some delayed processing on the frame right
37  * before it is returned to the caller.
38  *
39  * @note This code is called at some unspecified point after the frame is
40  * returned from the decoder's decode/receive_frame call. Therefore it cannot rely
41  * on AVCodecContext being in any specific state, so it does not get to
42  * access AVCodecContext directly at all. All the state it needs must be
43  * stored in the post_process_opaque object.
44  */
45  int (*post_process)(void *logctx, AVFrame *frame);
47  void (*post_process_opaque_free)(void *opaque);
48 
49  /**
50  * Per-frame private data for hwaccels.
51  */
52  void *hwaccel_priv;
53  void (*hwaccel_priv_free)(void *priv);
55 
56 /**
57  * avcodec_receive_frame() implementation for decoders.
58  */
60 
61 /**
62  * Called by decoders to get the next packet for decoding.
63  *
64  * @param pkt An empty packet to be filled with data.
65  * @return 0 if a new reference has been successfully written to pkt
66  * AVERROR(EAGAIN) if no data is currently available
67  * AVERROR_EOF if and end of stream has been reached, so no more data
68  * will be available
69  */
71 
72 /**
73  * Set various frame properties from the codec context / packet data.
74  */
76 
77 /**
78  * Make sure avctx.hw_frames_ctx is set. If it's not set, the function will
79  * try to allocate it from hw_device_ctx. If that is not possible, an error
80  * message is printed, and an error code is returned.
81  */
83  enum AVHWDeviceType dev_type);
84 
86 
87 /**
88  * Check whether the side-data of src contains a palette of
89  * size AVPALETTE_SIZE; if so, copy it to dst and return 1;
90  * else return 0.
91  * Also emit an error message upon encountering a palette
92  * with invalid size.
93  */
94 int ff_copy_palette(void *dst, const AVPacket *src, void *logctx);
95 
96 /**
97  * Perform decoder initialization and validation.
98  * Called when opening the decoder, before the FFCodec.init() call.
99  */
101 
102 /**
103  * Check that the provided frame dimensions are valid and set them on the codec
104  * context.
105  */
107 
108 /**
109  * Check that the provided sample aspect ratio is valid and set it on the codec
110  * context.
111  */
112 int ff_set_sar(AVCodecContext *avctx, AVRational sar);
113 
114 /**
115  * Select the (possibly hardware accelerated) pixel format.
116  * This is a wrapper around AVCodecContext.get_format() and should be used
117  * instead of calling get_format() directly.
118  *
119  * The list of pixel formats must contain at least one valid entry, and is
120  * terminated with AV_PIX_FMT_NONE. If it is possible to decode to software,
121  * the last entry in the list must be the most accurate software format.
122  * If it is not possible to decode to software, AVCodecContext.sw_pix_fmt
123  * must be set before calling this function.
124  */
125 int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt);
126 
127 /**
128  * Get a buffer for a frame. This is a wrapper around
129  * AVCodecContext.get_buffer() and should be used instead calling get_buffer()
130  * directly.
131  */
132 int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags);
133 
134 #define FF_REGET_BUFFER_FLAG_READONLY 1 ///< the returned buffer does not need to be writable
135 /**
136  * Identical in function to ff_get_buffer(), except it reuses the existing buffer
137  * if available.
138  */
140 
141 /**
142  * Add or update AV_FRAME_DATA_MATRIXENCODING side data.
143  */
145  enum AVMatrixEncoding matrix_encoding);
146 
147 #endif /* AVCODEC_DECODE_H */
ff_get_format
int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
Select the (possibly hardware accelerated) pixel format.
Definition: decode.c:1117
AVPixelFormat
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
FrameDecodeData
This struct stores per-frame lavc-internal data and is attached to it via private_ref.
Definition: decode.h:34
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:325
FrameDecodeData::hwaccel_priv_free
void(* hwaccel_priv_free)(void *priv)
Definition: decode.h:53
ff_set_dimensions
int ff_set_dimensions(AVCodecContext *s, int width, int height)
Check that the provided frame dimensions are valid and set them on the codec context.
Definition: utils.c:91
ff_decode_preinit
int ff_decode_preinit(AVCodecContext *avctx)
Perform decoder initialization and validation.
Definition: decode.c:1546
FrameDecodeData::post_process_opaque_free
void(* post_process_opaque_free)(void *opaque)
Definition: decode.h:47
ff_decode_frame_props
int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
Set various frame properties from the codec context / packet data.
Definition: decode.c:1264
pkt
AVPacket * pkt
Definition: movenc.c:59
ff_side_data_update_matrix_encoding
int ff_side_data_update_matrix_encoding(AVFrame *frame, enum AVMatrixEncoding matrix_encoding)
Add or update AV_FRAME_DATA_MATRIXENCODING side data.
Definition: utils.c:121
width
#define width
s
#define s(width, name)
Definition: cbs_vp9.c:256
FrameDecodeData::post_process_opaque
void * post_process_opaque
Definition: decode.h:46
ff_decode_receive_frame
int ff_decode_receive_frame(AVCodecContext *avctx, AVFrame *frame)
avcodec_receive_frame() implementation for decoders.
Definition: decode.c:670
AVHWDeviceType
AVHWDeviceType
Definition: hwcontext.h:27
ff_attach_decode_data
int ff_attach_decode_data(AVFrame *frame)
Definition: decode.c:1396
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1420
AVMatrixEncoding
AVMatrixEncoding
Definition: channel_layout.h:242
ff_decode_get_hw_frames_ctx
int ff_decode_get_hw_frames_ctx(AVCodecContext *avctx, enum AVHWDeviceType dev_type)
Make sure avctx.hw_frames_ctx is set.
Definition: decode.c:968
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
ff_set_sar
int ff_set_sar(AVCodecContext *avctx, AVRational sar)
Check that the provided sample aspect ratio is valid and set it on the codec context.
Definition: utils.c:106
ff_decode_get_packet
int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
Called by decoders to get the next packet for decoding.
Definition: decode.c:183
FrameDecodeData::post_process
int(* post_process)(void *logctx, AVFrame *frame)
The callback to perform some delayed processing on the frame right before it is returned to the calle...
Definition: decode.h:45
frame.h
buffer.h
height
#define height
ff_reget_buffer
int ff_reget_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Identical in function to ff_get_buffer(), except it reuses the existing buffer if available.
Definition: decode.c:1538
ff_copy_palette
int ff_copy_palette(void *dst, const AVPacket *src, void *logctx)
Check whether the side-data of src contains a palette of size AVPALETTE_SIZE; if so,...
Definition: decode.c:1634
avcodec.h
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
AVCodecContext
main external API structure.
Definition: avcodec.h:398
AVPacket
This structure stores compressed data.
Definition: packet.h:351
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
FrameDecodeData::hwaccel_priv
void * hwaccel_priv
Per-frame private data for hwaccels.
Definition: decode.h:52
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
hwcontext.h
int
int
Definition: ffmpeg_filter.c:156