FFmpeg
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Modules | |
Audio channel masks | |
A channel layout is a 64-bits integer with a bit set for every channel. | |
Audio channel convenience macros | |
Typedefs | |
typedef struct AVAudioFifo | AVAudioFifo |
Context for an Audio FIFO Buffer. More... | |
Functions | |
void | av_audio_fifo_free (AVAudioFifo *af) |
Free an AVAudioFifo. More... | |
AVAudioFifo * | av_audio_fifo_alloc (enum AVSampleFormat sample_fmt, int channels, int nb_samples) |
Allocate an AVAudioFifo. More... | |
int | av_audio_fifo_realloc (AVAudioFifo *af, int nb_samples) |
Reallocate an AVAudioFifo. More... | |
int | av_audio_fifo_write (AVAudioFifo *af, void **data, int nb_samples) |
Write data to an AVAudioFifo. More... | |
int | av_audio_fifo_read (AVAudioFifo *af, void **data, int nb_samples) |
Read data from an AVAudioFifo. More... | |
int | av_audio_fifo_drain (AVAudioFifo *af, int nb_samples) |
Drain data from an AVAudioFifo. More... | |
void | av_audio_fifo_reset (AVAudioFifo *af) |
Reset the AVAudioFifo buffer. More... | |
int | av_audio_fifo_size (AVAudioFifo *af) |
Get the current number of samples in the AVAudioFifo available for reading. More... | |
int | av_audio_fifo_space (AVAudioFifo *af) |
Get the current number of samples in the AVAudioFifo available for writing. More... | |
uint64_t | av_get_channel_layout (const char *name) |
Return a channel layout id that matches name, or 0 if no match is found. More... | |
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. More... | |
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. More... | |
int | av_get_channel_layout_nb_channels (uint64_t channel_layout) |
Return the number of channels in the channel layout. More... | |
int64_t | av_get_default_channel_layout (int nb_channels) |
Return default channel layout for a given number of channels. More... | |
int | av_get_channel_layout_channel_index (uint64_t channel_layout, uint64_t channel) |
Get the index of a channel in channel_layout. More... | |
uint64_t | av_channel_layout_extract_channel (uint64_t channel_layout, int index) |
Get the channel with the given index in channel_layout. More... | |
const char * | av_get_channel_name (uint64_t channel) |
Get the name of a given channel. More... | |
const char * | av_get_channel_description (uint64_t channel) |
Get the description of a given channel. More... | |
int | av_get_standard_channel_layout (unsigned index, uint64_t *layout, const char **name) |
Get the value and name of a standard channel layout. More... | |
Detailed Description
Typedef Documentation
typedef struct AVAudioFifo AVAudioFifo |
Context for an Audio FIFO Buffer.
- Operates at the sample level rather than the byte level.
- Supports multiple channels with either planar or packed sample format.
- Automatic reallocation when writing to a full buffer.
Definition at line 46 of file audio_fifo.h.
Function Documentation
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_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_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().
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_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().
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().
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().
Append a description of a channel layout to a bprint buffer.
Definition at line 148 of file channel_layout.c.
Referenced by av_get_channel_layout_string(), config_output(), and show_frame().
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 236 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_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 225 of file channel_layout.c.
Referenced by show_layouts().
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).
Example: "stereo+FC" = "2+FC" = "2c+1c" = "0x7"
Definition at line 132 of file channel_layout.c.
Referenced by channelmap_init(), ff_parse_channel_layout(), get_channel(), init(), init_audio(), join_init(), opt_channel_layout(), and parse_channel_name().
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 204 of file channel_layout.c.
Referenced by channelmap_config_input(), channelmap_init(), join_config_output(), parse_maps(), and read_restart_header().
int av_get_channel_layout_nb_channels | ( | uint64_t | channel_layout | ) |
Return the number of channels in the channel layout.
Definition at line 191 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_buffersrc_add_frame_internal(), av_channel_layout_extract_channel(), av_get_channel_description(), av_get_channel_layout_channel_index(), av_get_channel_name(), avcodec_open2(), avfilter_ref_buffer(), 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(), config_props_output(), cook_decode_init(), D(), dca_decode_frame(), ff_default_get_audio_buffer(), ff_filter_frame_framed(), ff_get_audio_buffer(), ff_init_buffer_info(), ff_merge_channel_layouts(), ff_mov_get_channel_layout_tag(), filter_frame(), get_channel(), get_valid_channel_layout(), init(), init_audio(), join_init(), lavfi_read_header(), main(), mov_read_dec3(), opt_channel_layout(), pick_format(), print_frame(), push_samples(), 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(), and thd_channel_layout_extract_channel().
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 182 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_parse_channel_layout(), 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().
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 214 of file channel_layout.c.
Referenced by channelmap_config_input(), init(), join_config_output(), and show_layouts().
int64_t av_get_default_channel_layout | ( | int | nb_channels | ) |
Return default channel layout for a given number of channels.
Definition at line 196 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_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 250 of file channel_layout.c.
Referenced by show_layouts().
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