Audio formats

Collaboration diagram for Audio formats:

Macros
#define	aout_FormatPrint(o, t, f)   aout_FormatPrint(VLC_OBJECT(o), t, f)

Functions
unsigned	aout_CheckChannelReorder (const uint32_t *, const uint32_t *, uint32_t mask, uint8_t *table)
	This function computes the reordering needed to go from pi_chan_order_in to pi_chan_order_out.
void	aout_ChannelReorder (void *ptr, size_t bytes, uint8_t channels, const uint8_t *chans_table, vlc_fourcc_t fourcc)
	Reorders audio samples within a block of linear audio interleaved samples.
bool	aout_CheckChannelExtraction (int *pi_selection, uint32_t *pi_layout, int *pi_channels, const uint32_t pi_order_dst[9], const uint32_t *pi_order_src, int i_channels)
	This function will compute the extraction parameter into pi_selection to go from i_channels with their type given by pi_order_src[] into the order describe by pi_order_dst.
void	aout_ChannelExtract (void *p_dst, int i_dst_channels, const void *p_src, int i_src_channels, int i_sample_count, const int *pi_selection, int i_bits_per_sample)
	Do the actual channels extraction using the parameters created by aout_CheckChannelExtraction.
void	aout_Interleave (void *dst, const void *const *planes, unsigned samples, unsigned channels, vlc_fourcc_t fourcc)
void	aout_Deinterleave (void *dst, const void *src, unsigned samples, unsigned channels, vlc_fourcc_t fourcc)
static unsigned	aout_FormatNbChannels (const audio_sample_format_t *fmt)
unsigned int	aout_BitsPerSample (vlc_fourcc_t i_format)
void	aout_FormatPrepare (audio_sample_format_t *p_format)
void	aout_FormatPrint (vlc_object_t *, const char *, const audio_sample_format_t *)
	Prints an audio sample format in a human-readable form.
const char *	aout_FormatPrintChannels (const audio_sample_format_t *)

Variables
static const uint32_t	pi_vlc_chan_order_wg4 []
	It describes the audio channel order VLC expect.

Detailed Description

Macro Definition Documentation

aout_FormatPrint

#define aout_FormatPrint	(		o,
			t,
			f
	)		aout_FormatPrint(VLC_OBJECT(o), t, f)

Function Documentation

aout_BitsPerSample()

unsigned int aout_BitsPerSample

(

vlc_fourcc_t

i_format

)

References AUDIO_ES, VLC_CODEC_ALAW, VLC_CODEC_F32B, VLC_CODEC_F32L, VLC_CODEC_F64B, VLC_CODEC_F64L, VLC_CODEC_MULAW, VLC_CODEC_S16B, VLC_CODEC_S16L, VLC_CODEC_S24B, VLC_CODEC_S24B32, VLC_CODEC_S24L, VLC_CODEC_S24L32, VLC_CODEC_S32B, VLC_CODEC_S32L, VLC_CODEC_S8, VLC_CODEC_U16B, VLC_CODEC_U16L, VLC_CODEC_U24B, VLC_CODEC_U24L, VLC_CODEC_U32B, VLC_CODEC_U32L, VLC_CODEC_U8, and vlc_fourcc_GetCodec().

Referenced by aout_ChannelReorder(), aout_FormatPrepare(), and EsOutUpdateInfo().

aout_ChannelExtract()

void aout_ChannelExtract	(	void *	p_dst,
		int	i_dst_channels,
		const void *	p_src,
		int	i_src_channels,
		int	i_sample_count,
		const int *	pi_selection,
		int	i_bits_per_sample
	)

Do the actual channels extraction using the parameters created by aout_CheckChannelExtraction.

XXX this function does not work in place (p_dst and p_src must not overlap). XXX Only 8, 16, 32, 64 bits per sample are supported.

References ExtractChannel().

aout_ChannelReorder()

void aout_ChannelReorder	(	void *	ptr,
		size_t	bytes,
		uint8_t	channels,
		const uint8_t *	chans_table,
		vlc_fourcc_t	fourcc
	)

Reorders audio samples within a block of linear audio interleaved samples.

Parameters

ptr	start address of the block of samples
bytes	size of the block in bytes (must be a multiple of the product of the channels count and the sample size)
channels	channels count (also length of the chans_table table)
chans_table	permutation table to reorder the channels (usually computed by aout_CheckChannelReorder())
fourcc	sample format (must be a linear sample format)

Note

The samples must be naturally aligned in memory.

aout_CheckChannelExtraction()

bool aout_CheckChannelExtraction	(	int *	pi_selection,
		uint32_t *	pi_layout,
		int *	pi_channels,
		const uint32_t	pi_order_dst[9],
		const uint32_t *	pi_order_src,
		int	i_channels
	)

This function will compute the extraction parameter into pi_selection to go from i_channels with their type given by pi_order_src[] into the order describe by pi_order_dst.

It will also set :

• *pi_channels as the number of channels that will be extracted which is lower (in case of non understood channels type) or equal to i_channels.
• the layout of the channels (*pi_layout).

It will return true if channel extraction is really needed, in which case aout_ChannelExtract must be used

XXX It must be used when the source may have channel type not understood by VLC. In this case the channel type pi_order_src[] must be set to 0. XXX It must also be used if multiple channels have the same type.

References AOUT_CHAN_MAX, and pi_vlc_chan_order_wg4.

aout_CheckChannelReorder()

unsigned aout_CheckChannelReorder	(	const uint32_t *	,
		const uint32_t *	,
		uint32_t	mask,
		uint8_t *	table
	)

This function computes the reordering needed to go from pi_chan_order_in to pi_chan_order_out.

If pi_chan_order_in or pi_chan_order_out is NULL, it will assume that vlc internal (WG4) order is requested.

aout_Deinterleave()

void aout_Deinterleave	(	void *	dst,
		const void *	src,
		unsigned	samples,
		unsigned	channels,
		vlc_fourcc_t	fourcc
	)

aout_FormatNbChannels()

static unsigned aout_FormatNbChannels ( const audio_sample_format_t *  fmt )

inlinestatic

References audio_format_t::i_physical_channels, and vlc_popcount.

Referenced by aout_filter_Create(), aout_FiltersNewWithClock(), aout_FormatPrepare(), aout_OutputNew(), and vlc_aout_stream_New().

aout_FormatPrepare()

void aout_FormatPrepare

(

audio_sample_format_t *

p_format

)

References aout_BitsPerSample(), aout_FormatNbChannels(), audio_format_t::i_bitspersample, audio_format_t::i_bytes_per_frame, audio_format_t::i_channels, audio_format_t::i_format, and audio_format_t::i_frame_length.

Referenced by aout_FiltersNewWithClock(), aout_FiltersPipelineCreate(), aout_OutputNew(), aout_SetWavePhysicalChannels(), aout_UpdateStereoMode(), ModuleThread_UpdateAudioFormat(), rtp_g722_init(), rtp_g726_init(), rtp_pcm_init(), and TryFormat().

aout_FormatPrint()

void aout_FormatPrint	(	vlc_object_t *	obj,
		const char *	psz_text,
		const audio_sample_format_t *	p_format
	)

Prints an audio sample format in a human-readable form.

References aout_FormatPrintChannels(), audio_format_t::i_bytes_per_frame, audio_format_t::i_format, audio_format_t::i_frame_length, audio_format_t::i_rate, and msg_Dbg.

aout_FormatPrintChannels()

const char * aout_FormatPrintChannels

(

const audio_sample_format_t *

p_format

)

References AOUT_CHAN_CENTER, AOUT_CHAN_LEFT, AOUT_CHAN_LFE, AOUT_CHAN_MIDDLELEFT, AOUT_CHAN_MIDDLERIGHT, AOUT_CHAN_REARCENTER, AOUT_CHAN_REARLEFT, AOUT_CHAN_REARRIGHT, AOUT_CHAN_RIGHT, AOUT_CHANMODE_DOLBYSTEREO, AOUT_CHANMODE_DUALMONO, AUDIO_CHANNEL_TYPE_AMBISONICS, audio_format_t::channel_type, audio_format_t::i_chan_mode, and audio_format_t::i_physical_channels.

Referenced by aout_AddMixModeChoice(), aout_FormatPrint(), aout_FormatsPrint(), and EsOutUpdateInfo().

aout_Interleave()

void aout_Interleave	(	void *	dst,
		const void *const *	planes,
		unsigned	samples,
		unsigned	channels,
		vlc_fourcc_t	fourcc
	)

Variable Documentation

pi_vlc_chan_order_wg4

const uint32_t pi_vlc_chan_order_wg4[]

static

Initial value:

=
{
     0x2 ,  0x4 ,
     0x100 ,  0x200 ,
     0x20 ,  0x40 ,  0x10 ,
     0x1 ,  0x1000 , 0
}

It describes the audio channel order VLC expect.

Referenced by aout_CheckChannelExtraction(), and aout_CheckChannelReorder().