Modules
	Audio channel masks
	A channel layout is a 64-bits integer with a bit set for every channel.

	Audio channel convenience macros

Functions
void	av_audio_fifo_free (AVAudioFifo *af)
	Free an AVAudioFifo.

AVAudioFifo *	av_audio_fifo_alloc (enum AVSampleFormat sample_fmt, int channels, int nb_samples)
	Allocate an AVAudioFifo.

int	av_audio_fifo_realloc (AVAudioFifo *af, int nb_samples)
	Reallocate an AVAudioFifo.

int	av_audio_fifo_write (AVAudioFifo af, void *data, int nb_samples)
	Write data to an AVAudioFifo.

int	av_audio_fifo_read (AVAudioFifo af, void *data, int nb_samples)
	Read data from an AVAudioFifo.

int	av_audio_fifo_drain (AVAudioFifo *af, int nb_samples)
	Drain data from an AVAudioFifo.

void	av_audio_fifo_reset (AVAudioFifo *af)
	Reset the AVAudioFifo buffer.

int	av_audio_fifo_size (AVAudioFifo *af)
	Get the current number of samples in the AVAudioFifo available for reading.

int	av_audio_fifo_space (AVAudioFifo *af)
	Get the current number of samples in the AVAudioFifo available for writing.

uint64_t	av_get_channel_layout (const char *name)
	Return a channel layout id that matches name, or 0 if no match is found.

void	av_get_channel_layout_string (char *buf, int buf_size, int nb_channels, uint64_t channel_layout)
	Return a description of a channel layout.

void	av_bprint_channel_layout (struct AVBPrint *bp, int nb_channels, uint64_t channel_layout)
	Append a description of a channel layout to a bprint buffer.

int	av_get_channel_layout_nb_channels (uint64_t channel_layout)
	Return the number of channels in the channel layout.

int64_t	av_get_default_channel_layout (int nb_channels)
	Return default channel layout for a given number of channels.

int	av_get_channel_layout_channel_index (uint64_t channel_layout, uint64_t channel)
	Get the index of a channel in channel_layout.

uint64_t	av_channel_layout_extract_channel (uint64_t channel_layout, int index)
	Get the channel with the given index in channel_layout.

const char *	av_get_channel_name (uint64_t channel)
	Get the name of a given channel.

const char *	av_get_channel_description (uint64_t channel)
	Get the description of a given channel.

int	av_get_standard_channel_layout (unsigned index, uint64_t layout, const char *name)
	Get the value and name of a standard channel layout.

Detailed Description

Function Documentation

void av_audio_fifo_free ( AVAudioFifo * af )

Free an AVAudioFifo.

Parameters

af	AVAudioFifo to free

Definition at line 45 of file audio_fifo.c.

Referenced by av_audio_fifo_alloc(), avresample_close(), and uninit().

AVAudioFifo* av_audio_fifo_alloc	(	enum AVSampleFormat	sample_fmt,
		int	channels,
		int	nb_samples
	)

Allocate an AVAudioFifo.

Parameters

sample_fmt	sample format
channels	number of channels
nb_samples	initial allocation size, in samples

Returns: newly allocated AVAudioFifo, or NULL on error

Definition at line 60 of file audio_fifo.c.

Referenced by av_buffersink_get_samples(), avresample_open(), config_output(), and config_props_output().

int av_audio_fifo_realloc	(	AVAudioFifo *	af,
		int	nb_samples
	)

Reallocate an AVAudioFifo.

Parameters

af	AVAudioFifo to reallocate
nb_samples	new allocation size, in samples

Returns: 0 if OK, or negative AVERROR code on failure

Definition at line 97 of file audio_fifo.c.

Referenced by av_audio_fifo_write(), and filter_frame().

int av_audio_fifo_write	(	AVAudioFifo *	af,
		void **	data,
		int	nb_samples
	)

Write data to an AVAudioFifo.

The AVAudioFifo will be reallocated automatically if the available space is less than nb_samples.

See Also: enum AVSampleFormat The documentation for AVSampleFormat describes the data layout.

Parameters

af	AVAudioFifo to write to
data	audio data plane pointers
nb_samples	number of samples to write

Returns: number of samples actually written, or negative AVERROR code on failure. If successful, the number of samples actually written will always be nb_samples.

Definition at line 113 of file audio_fifo.c.

Referenced by av_buffersink_get_samples(), ff_audio_data_add_to_fifo(), and filter_frame().

int av_audio_fifo_read	(	AVAudioFifo *	af,
		void **	data,
		int	nb_samples
	)

Read data from an AVAudioFifo.

See Also: enum AVSampleFormat The documentation for AVSampleFormat describes the data layout.

Parameters

af	AVAudioFifo to read from
data	audio data plane pointers
nb_samples	number of samples to read

Returns: number of samples actually read, or negative AVERROR code on failure. The number of samples actually read will not be greater than nb_samples, and will only be less than nb_samples if av_audio_fifo_size is less than nb_samples.

Definition at line 139 of file audio_fifo.c.

Referenced by avresample_read(), ff_audio_data_read_from_fifo(), output_frame(), push_samples(), and read_from_fifo().

int av_audio_fifo_drain	(	AVAudioFifo *	af,
		int	nb_samples
	)

Drain data from an AVAudioFifo.

Removes the data without reading it.

Parameters

af	AVAudioFifo to drain
nb_samples	number of samples to drain

Returns: 0 if OK, or negative AVERROR code on failure

Definition at line 159 of file audio_fifo.c.

Referenced by avresample_read().

void av_audio_fifo_reset ( AVAudioFifo * af )

Reset the AVAudioFifo buffer.

This empties all data in the buffer.

Parameters

af	AVAudioFifo to reset

Definition at line 176 of file audio_fifo.c.

int av_audio_fifo_size ( AVAudioFifo * af )

Get the current number of samples in the AVAudioFifo available for reading.

Parameters

af	the AVAudioFifo to query

Returns: number of samples available for reading

Definition at line 186 of file audio_fifo.c.

Referenced by av_audio_fifo_write(), av_buffersink_get_samples(), avresample_available(), avresample_convert(), avresample_set_compensation(), filter_frame(), get_available_samples(), handle_buffered_output(), push_samples(), and request_samples().

int av_audio_fifo_space ( AVAudioFifo * af )

Get the current number of samples in the AVAudioFifo available for writing.

Parameters

af	the AVAudioFifo to query

Returns: number of samples available for writing

Definition at line 191 of file audio_fifo.c.

Referenced by av_audio_fifo_write(), and filter_frame().

uint64_t av_get_channel_layout ( const char * name )

Return a channel layout id that matches name, or 0 if no match is found.

name can be one or several of the following notations, separated by '+' or '|':

the name of an usual channel layout (mono, stereo, 4.0, quad, 5.0, 5.0(side), 5.1, 5.1(side), 7.1, 7.1(wide), downmix);
the name of a single channel (FL, FR, FC, LFE, BL, BR, FLC, FRC, BC, SL, SR, TC, TFL, TFC, TFR, TBL, TBC, TBR, DL, DR);
a number of channels, in decimal, optionally followed by 'c', yielding the default channel layout for that number of channels (
See Also
av_get_default_channel_layout);
a channel layout mask, in hexadecimal starting with "0x" (see the AV_CH_* macros).

Warning: Starting from the next major bump the trailing character 'c' to specify a number of channels will be required, while a channel layout mask could also be specified as a decimal number (if and only if not followed by "c").

Example: "stereo+FC" = "2c+FC" = "2c+1c" = "0x7"

Definition at line 181 of file channel_layout.c.

Referenced by av_opt_set(), channelmap_init(), ff_parse_channel_layout(), get_channel(), init(), init_audio(), join_init(), opt_channel_layout(), and parse_channel_name().

void av_get_channel_layout_string	(	char *	buf,
		int	buf_size,
		int	nb_channels,
		uint64_t	channel_layout
	)

Return a description of a channel layout.

If nb_channels is <= 0, it is guessed from the channel_layout.

Parameters

buf	put here the string containing the channel layout
buf_size	size in bytes of the buffer

Definition at line 221 of file channel_layout.c.

Referenced by audio_decode_frame(), auto_matrix(), avcodec_open2(), avcodec_string(), channelmap_config_input(), channelmap_init(), clean_layout(), config_output(), config_props(), decode_audio(), dprint_options(), ff_alsa_open(), ff_audio_mix_set_matrix(), ff_tlog_link(), filter_frame(), guess_channel_layout(), guess_input_channel_layout(), init_filters(), main(), oggvorbis_init_encoder(), print_digraph(), print_link_prop(), query_formats(), and swr_init().

void av_bprint_channel_layout	(	struct AVBPrint *	bp,
		int	nb_channels,
		uint64_t	channel_layout
	)

Append a description of a channel layout to a bprint buffer.

Definition at line 187 of file channel_layout.c.

Referenced by av_get_channel_layout_string(), config_output(), show_frame(), and show_stream().

int av_get_channel_layout_nb_channels ( uint64_t channel_layout )

Return the number of channels in the channel layout.

Definition at line 230 of file channel_layout.c.

Referenced by audio_decode_frame(), audio_encode_example(), audio_open(), auto_matrix(), av_bprint_channel_layout(), av_buffersrc_add_frame_flags(), av_channel_layout_extract_channel(), av_get_channel_description(), av_get_channel_layout_channel_index(), av_get_channel_name(), avcodec_open2(), avresample_build_matrix(), avresample_get_matrix(), avresample_open(), avresample_set_channel_mapping(), avresample_set_matrix(), buffer_offset(), calc_ptr_alignment(), channelmap_config_input(), channelmap_filter_frame(), channelmap_init(), config_audio_output(), config_output(), config_props(), cook_decode_init(), dca_decode_frame(), ff_default_get_audio_buffer(), ff_filter_frame_framed(), ff_init_buffer_info(), ff_merge_channel_layouts(), ff_mov_get_channel_layout_tag(), ff_parse_channel_layout(), filter_frame(), get_channel(), get_stream_info(), get_valid_channel_layout(), init(), init_audio(), join_init(), main(), mov_read_dec3(), opt_channel_layout(), pick_format(), print_frame(), query_formats(), return_audio_frame(), sane_layout(), select_channel_layout(), send_silence(), swap_channel_layouts_on_filter(), swr_alloc_set_opts(), swr_init(), swr_set_matrix(), swri_rematrix(), swri_rematrix_init(), swri_rematrix_init_x86(), and thd_channel_layout_extract_channel().

int64_t av_get_default_channel_layout ( int nb_channels )

Return default channel layout for a given number of channels.

Definition at line 235 of file channel_layout.c.

Referenced by audio_decode_frame(), audio_open(), channelmap_init(), configure_output_audio_filter(), encode_init(), get_channel_layout_single(), guess_channel_layout(), guess_input_channel_layout(), init(), init_filters(), query_formats(), set_channel_info(), and swr_init().

int av_get_channel_layout_channel_index	(	uint64_t	channel_layout,
		uint64_t	channel
	)

Get the index of a channel in channel_layout.

Parameters

channel a channel layout describing exactly one channel which must be present in channel_layout.

Returns: index of channel in channel_layout on success, a negative AVERROR on error.

Definition at line 243 of file channel_layout.c.

Referenced by channelmap_config_input(), channelmap_init(), join_config_output(), parse_maps(), and read_restart_header().

uint64_t av_channel_layout_extract_channel	(	uint64_t	channel_layout,
		int	index
	)

Get the channel with the given index in channel_layout.

Definition at line 275 of file channel_layout.c.

Referenced by filter_frame(), guess_map_any(), init(), join_config_output(), join_init(), and query_formats().

const char* av_get_channel_name ( uint64_t channel )

Get the name of a given channel.

Returns: channel name on success, NULL on error.

Definition at line 253 of file channel_layout.c.

Referenced by channelmap_config_input(), init(), join_config_output(), and show_layouts().

const char* av_get_channel_description ( uint64_t channel )

Get the description of a given channel.

Parameters

channel a channel layout with a single channel

Returns: channel description on success, NULL on error

Definition at line 264 of file channel_layout.c.

Referenced by show_layouts().

int av_get_standard_channel_layout	(	unsigned	index,
		uint64_t *	layout,
		const char **	name
	)

Get the value and name of a standard channel layout.

Parameters

[in]	index	index in an internal list, starting at 0
[out]	layout	channel layout mask
[out]	name	name of the layout

Returns: 0 if the layout exists, <0 if index is beyond the limits

Definition at line 289 of file channel_layout.c.

Referenced by show_layouts().

Modules

Functions

Detailed Description

Function Documentation