Utility functions

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

Topics
	Pixel formats
	Functions for working with pixel formats.

Functions
void	avcodec_string (char *buf, int buf_size, AVCodecContext *enc, int encode)
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 codec state / flush internal buffers.
int	av_get_audio_frame_duration (AVCodecContext *avctx, int frame_bytes)
	Return audio frame duration.
void	av_fast_padded_malloc (void *ptr, unsigned int *size, size_t min_size)
	Same behaviour av_fast_malloc but the buffer has additional AV_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.
int	avcodec_is_open (AVCodecContext *s)

Detailed Description

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

Function Documentation

avcodec_string()

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

avcodec_default_execute()

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

avcodec_default_execute2()

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

avcodec_fill_audio_frame()

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

avcodec_flush_buffers()

void avcodec_flush_buffers

(

AVCodecContext *

avctx

)

Reset the internal codec state / flush internal buffers.

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

Note

for decoders, this function just releases any references the decoder might keep internally, but the caller's references remain valid.

for encoders, this function will only do something if the encoder declares support for AV_CODEC_CAP_ENCODER_FLUSH. When called, the encoder will drain any remaining packets, and can then be reused for a different stream (as opposed to sending a null frame which will leave the encoder in a permanent EOF state after draining). This can be desirable if the cost of tearing down and replacing the encoder instance is high.

av_get_audio_frame_duration()

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.

av_fast_padded_malloc()

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

Same behaviour av_fast_malloc but the buffer has additional AV_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.

av_fast_padded_mallocz()

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.

avcodec_is_open()

int avcodec_is_open

(

AVCodecContext *

s

)

Returns

a positive value if s is open (i.e. avcodec_open2() was called on it), 0 otherwise.