Miscellaneous utility functions related to both encoding and decoding (or neither). More...

Modules
	Pixel formats
	Functions for working with pixel formats.

	FFT functions

Data Structures
struct	AVBitStreamFilterContext

struct	AVBitStreamFilter

Enumerations
enum	AVLockOp { AV_LOCK_CREATE, AV_LOCK_OBTAIN, AV_LOCK_RELEASE, AV_LOCK_DESTROY }
	Lock operation used by lockmgr. More...

Functions
void	avcodec_set_dimensions (AVCodecContext *s, int width, int height)

size_t	av_get_codec_tag_string (char *buf, size_t buf_size, unsigned int codec_tag)
	Put a string representing the codec tag codec_tag in buf.

void	avcodec_string (char buf, int buf_size, AVCodecContext enc, int encode)

const char *	av_get_profile_name (const AVCodec *codec, int profile)
	Return a name for the specified profile, if available.

int	avcodec_default_execute (AVCodecContext c, int(func)(AVCodecContext c2, void arg2), void arg, int ret, int count, int size)

int	avcodec_default_execute2 (AVCodecContext c, int(func)(AVCodecContext c2, void arg2, int, int), void arg, int ret, int count)

int	avcodec_fill_audio_frame (AVFrame frame, int nb_channels, enum AVSampleFormat sample_fmt, const uint8_t buf, int buf_size, int align)
	Fill AVFrame audio data and linesize pointers.

void	avcodec_flush_buffers (AVCodecContext *avctx)
	Reset the internal decoder state / flush internal buffers.

int	av_get_bits_per_sample (enum AVCodecID codec_id)
	Return codec bits per sample.

enum AVCodecID	av_get_pcm_codec (enum AVSampleFormat fmt, int be)
	Return the PCM codec associated with a sample format.

int	av_get_exact_bits_per_sample (enum AVCodecID codec_id)
	Return codec bits per sample.

int	av_get_audio_frame_duration (AVCodecContext *avctx, int frame_bytes)
	Return audio frame duration.

void	av_register_bitstream_filter (AVBitStreamFilter *bsf)
	Register a bitstream filter.

AVBitStreamFilterContext *	av_bitstream_filter_init (const char *name)
	Create and initialize a bitstream filter context given a bitstream filter name.

int	av_bitstream_filter_filter (AVBitStreamFilterContext bsfc, AVCodecContext avctx, const char args, uint8_t poutbuf, int poutbuf_size, const uint8_t *buf, int buf_size, int keyframe)
	Filter bitstream.

void	av_bitstream_filter_close (AVBitStreamFilterContext *bsf)
	Release bitstream filter context.

AVBitStreamFilter *	av_bitstream_filter_next (AVBitStreamFilter *f)
	If f is NULL, return the first registered bitstream filter, if f is non-NULL, return the next registered bitstream filter after f, or NULL if f is the last one.

void *	av_fast_realloc (void ptr, unsigned int size, size_t min_size)
	Reallocate the given block if it is not large enough, otherwise do nothing.

void	av_fast_malloc (void ptr, unsigned int size, size_t min_size)
	Allocate a buffer, reusing the given one if large enough.

void	av_fast_padded_malloc (void ptr, unsigned int size, size_t min_size)
	Same behaviour av_fast_malloc but the buffer has additional FF_INPUT_BUFFER_PADDING_SIZE at the end which will always be 0.

void	av_fast_padded_mallocz (void ptr, unsigned int size, size_t min_size)
	Same behaviour av_fast_padded_malloc except that buffer will always be 0-initialized after call.

unsigned int	av_xiphlacing (unsigned char *s, unsigned int v)
	Encode extradata length to a buffer.

void	av_register_hwaccel (AVHWAccel *hwaccel)
	Register the hardware accelerator hwaccel.

AVHWAccel *	av_hwaccel_next (AVHWAccel *hwaccel)
	If hwaccel is NULL, returns the first registered hardware accelerator, if hwaccel is non-NULL, returns the next registered hardware accelerator after hwaccel, or NULL if hwaccel is the last one.

int	av_lockmgr_register (int(cb)(void *mutex, enum AVLockOp op))
	Register a user provided lock manager supporting the operations specified by AVLockOp.

enum AVMediaType	avcodec_get_type (enum AVCodecID codec_id)
	Get the type of the given codec.

const char *	avcodec_get_name (enum AVCodecID id)
	Get the name of a codec.

int	avcodec_is_open (AVCodecContext *s)

int	av_codec_is_encoder (const AVCodec *codec)

int	av_codec_is_decoder (const AVCodec *codec)

const AVCodecDescriptor *	avcodec_descriptor_get (enum AVCodecID id)

const AVCodecDescriptor *	avcodec_descriptor_next (const AVCodecDescriptor *prev)
	Iterate over all codec descriptors known to libavcodec.

const AVCodecDescriptor *	avcodec_descriptor_get_by_name (const char *name)

Detailed Description

Miscellaneous utility functions related to both encoding and decoding (or neither).

Enumeration Type Documentation

enum AVLockOp

Lock operation used by lockmgr.

Enumerator:

AV_LOCK_CREATE	Create a mutex.
AV_LOCK_OBTAIN	Lock the mutex.
AV_LOCK_RELEASE	Unlock the mutex.
AV_LOCK_DESTROY	Free mutex resources.

Definition at line 4955 of file avcodec.h.

Function Documentation

void avcodec_set_dimensions	(	AVCodecContext *	s,
		int	width,
		int	height
	)

Definition at line 234 of file utils.c.

Referenced by apply_param_change(), av_mpeg4_decode_header(), avcodec_open2(), avpriv_dirac_parse_sequence_header(), avs_decode_init(), brpix_decode_frame(), cdxl_decode_frame(), cmv_process_header(), decode_frame(), decode_frame_headers(), decode_init(), dnxhd_decode_frame(), dvdsub_parse_extradata(), dvvideo_decode_frame(), execute_code(), ff_h263_decode_frame(), ff_ivi_decode_frame(), ff_mjpeg_decode_sof(), ff_rv34_decode_frame(), ff_vc1_decode_entry_point(), ff_vc1_decode_sequence_header(), flashsv_decode_frame(), g2m_decode_frame(), gif_decode_frame(), h261_decode_frame(), init_image(), libopenjpeg_decode_frame(), mpeg_decode_postinit(), mpegvideo_extract_headers(), mvc_decode_init(), parse_presentation_segment(), pcx_decode_frame(), process_frame_obj(), ptx_decode_frame(), rv20_decode_picture_header(), smvjpeg_decode_frame(), sunrast_decode_frame(), svq1_decode_frame(), tgq_decode_frame(), tgv_decode_frame(), theora_header(), tqi_decode_frame(), truemotion1_decode_header(), txd_decode_frame(), update_dimensions(), vp56_size_changed(), vp5_parse_header(), vp6_parse_header(), vp8_decode(), and vp8_lossless_decode_frame().

size_t av_get_codec_tag_string	(	char *	buf,
		size_t	buf_size,
		unsigned int	codec_tag
	)

Put a string representing the codec tag codec_tag in buf.

Parameters

buf_size size in bytes of buf

Returns: the length of the string that would have been generated if enough space had been available, excluding the trailing null

Definition at line 2659 of file utils.c.

Referenced by avcodec_string(), init_muxer(), main(), mov_write_hdlr_tag(), print_pix_fmt_fourccs(), rsd_read_header(), and show_stream().

void avcodec_string	(	char *	buf,
		int	buf_size,
		AVCodecContext *	enc,
		int	encode
	)

Definition at line 2679 of file utils.c.

Referenced by avformat_find_stream_info(), and dump_stream_format().

const char* av_get_profile_name	(	const AVCodec *	codec,
		int	profile
	)

Return a name for the specified profile, if available.

Parameters

codec	the codec that is searched for the given profile
profile	the profile value for which a name is requested

Returns: A name for the profile if found, NULL otherwise.

Definition at line 2815 of file utils.c.

Referenced by avcodec_string(), and show_stream().

int avcodec_default_execute	(	AVCodecContext *	c,
		int()(AVCodecContext c2, void *arg2)	func,
		void *	arg,
		int *	ret,
		int	count,
		int	size
	)

Definition at line 1010 of file utils.c.

Referenced by avcodec_get_context_defaults3(), and avcodec_thread_execute().

int avcodec_default_execute2	(	AVCodecContext *	c,
		int()(AVCodecContext c2, void *arg2, int, int)	func,
		void *	arg,
		int *	ret,
		int	count
	)

Referenced by avcodec_get_context_defaults3().

int avcodec_fill_audio_frame	(	AVFrame *	frame,
		int	nb_channels,
		enum AVSampleFormat	sample_fmt,
		const uint8_t *	buf,
		int	buf_size,
		int	align
	)

Fill AVFrame audio data and linesize pointers.

The buffer buf must be a preallocated buffer with a size big enough to contain the specified samples amount. The filled AVFrame data pointers will point to this buffer.

AVFrame extended_data channel pointers are allocated if necessary for planar audio.

Parameters

frame	the AVFrame frame->nb_samples must be set prior to calling the function. This function fills in frame->data, frame->extended_data, frame->linesize[0].
nb_channels	channel count
sample_fmt	sample format
buf	buffer to use for frame data
buf_size	size of buffer
align	plane size sample alignment (0 = default)

Returns: >=0 on success, negative error code on failure

Todo:: return the size in bytes required to store the samples in case of success, at the next libavutil bump

Examples:: doc/examples/decoding_encoding.c, and doc/examples/muxing.c.

Definition at line 432 of file utils.c.

Referenced by audio_encode_example(), and write_audio_frame().

void avcodec_flush_buffers ( AVCodecContext * avctx )

Reset the internal decoder state / flush internal buffers.

Should be called e.g. when seeking or when switching to a different stream.

Note: when refcounted frames are not used (i.e. avctx->refcounted_frames is 0), this invalidates the frames previously returned from the decoder. When refcounted frames are used, the decoder just releases any references it might keep internally, but the caller's reference remains valid.

Definition at line 2856 of file utils.c.

Referenced by get_video_frame(), rewind_file(), subtitle_thread(), and video_thread().

int av_get_bits_per_sample ( enum AVCodecID codec_id )

Return codec bits per sample.

Parameters

[in] codec_id the codec

Returns: Number of bits per sample or zero if unknown for the given codec.

Definition at line 2941 of file utils.c.

Referenced by adpcm_encode_init(), aiff_write_header(), avformat_find_stream_info(), caf_write_header(), epaf_read_header(), ff_alsa_open(), ff_audio_interleave_init(), ff_pcm_read_seek(), ff_put_wav_header(), ff_voc_get_packet(), g722_read_header(), get_aiff_header(), get_bit_rate(), gxf_packet(), iff_read_header(), init_muxer(), ircam_read_header(), mkv_write_tracks(), mov_get_codec_tag(), mov_parse_stsd_audio(), mov_write_audio_tag(), mov_write_header(), mxf_set_audio_pts(), mxf_write_generic_sound_common(), oma_read_header(), pcm_decode_frame(), pcm_decode_init(), pcm_encode_frame(), pcm_encode_init(), pcm_read_header(), pulse_read_header(), read_header(), rso_read_header(), and show_stream().

enum AVCodecID av_get_pcm_codec	(	enum AVSampleFormat	fmt,
		int	be
	)

Return the PCM codec associated with a sample format.

Parameters

be	endianness, 0 for little, 1 for big, -1 (or anything else) for native

Returns: AV_CODEC_ID_PCM_* or AV_CODEC_ID_NONE

Definition at line 2920 of file utils.c.

Referenced by lavfi_read_header().

int av_get_exact_bits_per_sample ( enum AVCodecID codec_id )

Return codec bits per sample.

Only return non-zero if the bits per sample is exactly correct, not an approximation.

Parameters

[in] codec_id the codec

Returns: Number of bits per sample or zero if unknown for the given codec.

Definition at line 2870 of file utils.c.

Referenced by av_get_audio_frame_duration(), av_get_bits_per_sample(), and new_output_stream().

int av_get_audio_frame_duration	(	AVCodecContext *	avctx,
		int	frame_bytes
	)

Return audio frame duration.

Parameters

avctx	codec context
frame_bytes	size of the frame, or 0 if unknown

Returns: frame duration, in samples, if known. 0 if not able to determine.

Definition at line 2959 of file utils.c.

Referenced by adp_read_header(), build_frame_code(), do_streamcopy(), ff_get_audio_frame_size(), ff_parse_specific_params(), ff_put_wav_header(), get_aiff_header(), rsd_read_header(), rtp_send_ilbc(), and rtp_write_header().

void av_register_bitstream_filter ( AVBitStreamFilter * bsf )

Register a bitstream filter.

The filter will be accessible to the application code through av_bitstream_filter_next() or can be directly initialized with av_bitstream_filter_init().

See Also: avcodec_register_all()

Definition at line 37 of file bitstream_filter.c.

AVBitStreamFilterContext* av_bitstream_filter_init ( const char * name )

Create and initialize a bitstream filter context given a bitstream filter name.

The returned context must be freed with av_bitstream_filter_close().

Parameters

name	the name of the bitstream filter

Returns: a bitstream filter context if a matching filter was found and successfully initialized, NULL otherwise

Definition at line 44 of file bitstream_filter.c.

Referenced by init(), new_output_stream(), parse_bsfs(), and Stagefright_init().

int av_bitstream_filter_filter	(	AVBitStreamFilterContext *	bsfc,
		AVCodecContext *	avctx,
		const char *	args,
		uint8_t **	poutbuf,
		int *	poutbuf_size,
		const uint8_t *	buf,
		int	buf_size,
		int	keyframe
	)

Filter bitstream.

This function filters the buffer buf with size buf_size, and places the filtered buffer in the buffer pointed to by poutbuf.

The output buffer must be freed by the caller.

Parameters

bsfc	bitstream filter context created by av_bitstream_filter_init()
avctx	AVCodecContext accessed by the filter, may be NULL. If specified, this must point to the encoder context of the output stream the packet is sent to.
args	arguments which specify the filter configuration, may be NULL
poutbuf	pointer which is updated to point to the filtered buffer
poutbuf_size	pointer which is updated to the filtered buffer size in bytes
buf	buffer containing the data to filter
buf_size	size in bytes of buf
keyframe	set to non-zero if the buffer to filter corresponds to a key-frame packet data

Returns: >= 0 in case of success, or a negative error code in case of failure

If the return value is positive, an output buffer is allocated and is availble in *poutbuf, and is distinct from the input buffer.

If the return value is 0, the output buffer is not allocated and should be considered identical to the input buffer, or in case *poutbuf was set it points to the input buffer (not necessarily to its starting address).

Definition at line 73 of file bitstream_filter.c.

Referenced by decode(), filter_packet(), init(), Stagefright_decode_frame(), and write_frame().

void av_bitstream_filter_close ( AVBitStreamFilterContext * bsf )

Release bitstream filter context.

Parameters

bsf	the bitstream filter context created with av_bitstream_filter_init(), can be NULL

Definition at line 62 of file bitstream_filter.c.

Referenced by close_slaves(), ffmpeg_cleanup(), Stagefright_close(), Stagefright_init(), and uninit().

AVBitStreamFilter* av_bitstream_filter_next ( AVBitStreamFilter * f )

If f is NULL, return the first registered bitstream filter, if f is non-NULL, return the next registered bitstream filter after f, or NULL if f is the last one.

This function can be used to iterate over all registered bitstream filters.

Definition at line 29 of file bitstream_filter.c.

Referenced by show_bsfs().

void* av_fast_realloc	(	void *	ptr,
		unsigned int *	size,
		size_t	min_size
	)

Reallocate the given block if it is not large enough, otherwise do nothing.

See Also: av_realloc

Definition at line 120 of file utils.c.

Referenced by caf_write_packet(), decode_frame(), decode_frame_header(), dirac_combine_frame(), ff_add_index_entry(), ff_af_queue_add(), ff_combine_frame(), ff_mms_asf_header_parser(), ff_subtitles_queue_insert(), ff_thread_release_buffer(), ff_vaapi_alloc_slice(), ff_vaapi_commit_slices(), ff_vdpau_add_buffer(), ff_vdpau_add_data_chunk(), flac_fifo_read_wrap(), get_stats(), mxg_update_cache(), read_frame(), shorten_decode_frame(), spdif_header_eac3(), and vda_h264_decode_slice().

void av_fast_malloc	(	void *	ptr,
		unsigned int *	size,
		size_t	min_size
	)

Allocate a buffer, reusing the given one if large enough.

Contrary to av_fast_realloc the current buffer contents might not be preserved and on error the old buffer is freed, thus no special handling to avoid memleaks is necessary.

Parameters

ptr	pointer to pointer to already allocated buffer, overwritten with pointer to new buffer
size	size of the buffer *ptr points to
min_size	minimum size of ptr buffer after returning, ptr will be NULL and *size 0 if an error occurred.

Definition at line 153 of file utils.c.

Referenced by allocate_buffers(), ape_decode_frame(), audio_decode_frame(), codec_reinit(), dca_decode_frame(), decode_8(), decode_frame(), decode_i_frame(), decode_p_frame(), ff_h263_decode_frame(), ff_hevc_extract_rbsp(), ff_mpeg_update_thread_context(), gif_decode_frame(), gif_read_image(), hevc_frame_start(), id3v2_parse(), ljpeg_decode_rgb_scan(), mp_decode_frame(), parse_picture_segment(), pmp_packet(), reconfigure_at_keyframe(), spdif_header_dts4(), spdif_write_packet(), submit_packet(), svq3_decode_frame(), tak_decode_frame(), truemotion1_decode_header(), truemotion1_decode_init(), update_md5_sum(), utvideo_encode_frame(), and verify_md5().

void av_fast_padded_malloc	(	void *	ptr,
		unsigned int *	size,
		size_t	min_size
	)

Same behaviour av_fast_malloc but the buffer has additional FF_INPUT_BUFFER_PADDING_SIZE at the end which will always be 0.

In addition the whole buffer will initially and after resizes be 0-initialized so that no uninitialized data will ever appear.

Definition at line 158 of file utils.c.

Referenced by allocate_buffers(), allocate_buffers2(), cdxl_decode_frame(), cllc_decode_frame(), decode_block(), decode_frame(), deinvert_buffer(), ebml_read_binary(), encode_frame(), ff_alloc_packet2(), ff_h264_decode_nal(), ff_mjpeg_find_marker(), init_buffers(), mimic_decode_frame(), mpc7_decode_frame(), tqi_decode_frame(), wavpack_encode_block(), wavpack_encode_frame(), and wv_stereo().

void av_fast_padded_mallocz	(	void *	ptr,
		unsigned int *	size,
		size_t	min_size
	)

Same behaviour av_fast_padded_malloc except that buffer will always be 0-initialized after call.

Definition at line 170 of file utils.c.

Referenced by decode_frame(), and encode_frame().

unsigned int av_xiphlacing	(	unsigned char *	s,
		unsigned int	v
	)

Encode extradata length to a buffer.

Used by xiph codecs.

Parameters

s	buffer to write to; must be at least (v/255+1) bytes long
v	size of extradata in bytes

Returns: number of bytes written to the buffer.

Definition at line 3132 of file utils.c.

Referenced by fixup_vorbis_headers(), oggvorbis_encode_init(), parse_packed_headers(), and put_main_header().

void av_register_hwaccel ( AVHWAccel * hwaccel )

Register the hardware accelerator hwaccel.

Definition at line 3184 of file utils.c.

AVHWAccel* av_hwaccel_next ( AVHWAccel * hwaccel )

If hwaccel is NULL, returns the first registered hardware accelerator, if hwaccel is non-NULL, returns the next registered hardware accelerator after hwaccel, or NULL if hwaccel is the last one.

Definition at line 3192 of file utils.c.

Referenced by ff_find_hwaccel().

int av_lockmgr_register ( int(*)(void **mutex, enum AVLockOp op) cb )

Register a user provided lock manager supporting the operations specified by AVLockOp.

mutex points to a (void *) where the lockmgr should store/get a pointer to a user allocated mutex. It's NULL upon AV_LOCK_CREATE and != NULL for all other ops.

Parameters

cb User defined callback. Note: FFmpeg may invoke calls to this callback during the call to av_lockmgr_register(). Thus, the application must be prepared to handle that. If cb is set to NULL the lockmgr will be unregistered. Also note that during unregistration the previously registered lockmgr callback may also be invoked.

Definition at line 3208 of file utils.c.

Referenced by do_exit(), and main().

enum AVMediaType avcodec_get_type ( enum AVCodecID codec_id )

Get the type of the given codec.

Definition at line 3359 of file utils.c.

Referenced by mkv_query_codec().

const char* avcodec_get_name ( enum AVCodecID id )

Get the name of a codec.