ALSA input and output: common code. More...

#include "config_components.h"
#include <alsa/asoundlib.h>
#include "avdevice.h"
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/mem.h"
#include "alsa.h"

Macros
#define	MAKE_REORDER_FUNC(NAME, TYPE, CHANNELS, LAYOUT, MAP)

#define	MAKE_REORDER_FUNCS(CHANNELS, LAYOUT, MAP)

#define	FORMAT_I8 0

#define	FORMAT_I16 1

#define	FORMAT_I32 2

#define	FORMAT_F32 3

#define	PICK_REORDER(layout)

Functions
static av_cold snd_pcm_format_t	codec_id_to_pcm_format (int codec_id)

	MAKE_REORDER_FUNCS (5, out_50, out[0]=in[0];out[1]=in[1];out[2]=in[3];out[3]=in[4];out[4]=in[2];)

static enum AVChannel	alsa_chmap_pos_to_av_chan (unsigned int pos)

static int	alsa_get_chmap (AVFormatContext ctx, snd_pcm_t h, AVChannelLayout *layout)

static av_cold int	find_reorder_func (AlsaData s, int codec_id, const AVChannelLayout layout, int out)

av_cold int	ff_alsa_open (AVFormatContext ctx, snd_pcm_stream_t mode, unsigned int sample_rate, AVChannelLayout layout, enum AVCodecID codec_id)
	Open an ALSA PCM.

av_cold int	ff_alsa_close (AVFormatContext *s1)
	Close the ALSA PCM.

int	ff_alsa_xrun_recover (AVFormatContext *s1, int err)
	Try to recover from ALSA buffer underrun.

int	ff_alsa_extend_reorder_buf (AlsaData *s, int min_size)

int	ff_alsa_get_device_list (AVDeviceInfoList *device_list, snd_pcm_stream_t stream_type)

Variables
	alsa_chmap_table []

Detailed Description

ALSA input and output: common code.

Author: Luca Abeni ( lucabe72 email it ); Benoit Fouet ( benoit fouet free fr ); Nicolas George ( nicolas george normalesup org )

Definition in file alsa.c.

Macro Definition Documentation

◆ MAKE_REORDER_FUNC

#define MAKE_REORDER_FUNC	(	NAME,
		TYPE,
		CHANNELS,
		LAYOUT,
		MAP )

Value:

static void alsa_reorder_ ## NAME ## _ ## LAYOUT(const void *in_v,          \
                                                 void *out_v,               \
                                                 int n)                     \
{                                                                           \
    const TYPE *in = in_v;                                                  \
    TYPE      *out = out_v;                                                 \
                                                                            \
    while (n-- > 0) {                                                       \
        MAP                                                                 \
        in  += CHANNELS;                                                    \
        out += CHANNELS;                                                    \
    }                                                                       \
}

Definition at line 68 of file alsa.c.

◆ MAKE_REORDER_FUNCS

#define MAKE_REORDER_FUNCS	(	CHANNELS,
		LAYOUT,
		MAP )

Value:

    MAKE_REORDER_FUNC(int8,  int8_t,  CHANNELS, LAYOUT, MAP) \
    MAKE_REORDER_FUNC(int16, int16_t, CHANNELS, LAYOUT, MAP) \
    MAKE_REORDER_FUNC(int32, int32_t, CHANNELS, LAYOUT, MAP) \
    MAKE_REORDER_FUNC(f32,   float,   CHANNELS, LAYOUT, MAP)

Definition at line 83 of file alsa.c.

◆ FORMAT_I8

#define FORMAT_I8 0

Referenced by find_reorder_func(), and MAKE_REORDER_FUNCS().

◆ FORMAT_I16

#define FORMAT_I16 1

Referenced by find_reorder_func(), and MAKE_REORDER_FUNCS().

◆ FORMAT_I32

#define FORMAT_I32 2

Referenced by find_reorder_func(), and MAKE_REORDER_FUNCS().

◆ FORMAT_F32

#define FORMAT_F32 3

Referenced by find_reorder_func(), and MAKE_REORDER_FUNCS().

◆ PICK_REORDER

#define PICK_REORDER ( layout )

Value:

switch(format) {\
    case FORMAT_I8:  s->reorder_func = alsa_reorder_int8_out_ ##layout;  break;\
    case FORMAT_I16: s->reorder_func = alsa_reorder_int16_out_ ##layout; break;\
    case FORMAT_I32: s->reorder_func = alsa_reorder_int32_out_ ##layout; break;\
    case FORMAT_F32: s->reorder_func = alsa_reorder_f32_out_ ##layout;   break;\
}

Referenced by find_reorder_func().

Function Documentation

◆ codec_id_to_pcm_format()

static av_cold snd_pcm_format_t codec_id_to_pcm_format ( int codec_id )

static

Definition at line 41 of file alsa.c.

Referenced by ff_alsa_open().

◆ MAKE_REORDER_FUNCS()

MAKE_REORDER_FUNCS	(	5	,
		out_50	,
		out	[0] = in[0]; out[1] = in[1]; out[2] = in[3]; out[3] = in[4]; out[4] = in[2]; )

Definition at line 89 of file alsa.c.

◆ alsa_chmap_pos_to_av_chan()

static enum AVChannel alsa_chmap_pos_to_av_chan ( unsigned int pos )

static

Definition at line 166 of file alsa.c.

Referenced by alsa_get_chmap().

◆ alsa_get_chmap()

static int alsa_get_chmap	(	AVFormatContext *	ctx,
		snd_pcm_t *	h,
		AVChannelLayout *	layout )

static

Definition at line 174 of file alsa.c.

Referenced by ff_alsa_open().

◆ find_reorder_func()

static av_cold int find_reorder_func	(	AlsaData *	s,
		int	codec_id,
		const AVChannelLayout *	layout,
		int	out )

static

Definition at line 212 of file alsa.c.

Referenced by ff_alsa_open().

◆ ff_alsa_open()

av_cold int ff_alsa_open	(	AVFormatContext *	s,
		snd_pcm_stream_t	mode,
		unsigned int *	sample_rate,
		AVChannelLayout *	layout,
		enum AVCodecID *	codec_id )

Open an ALSA PCM.

Parameters

s	media file handle
mode	either SND_PCM_STREAM_CAPTURE or SND_PCM_STREAM_PLAYBACK
sample_rate	in: requested sample rate; out: actually selected sample rate
layout	in: requested channel layout, or nb_channels=0 for auto-detect; out: actually selected channel layout
codec_id	in: requested AVCodecID or AV_CODEC_ID_NONE; out: actually selected AVCodecID, changed only if AV_CODEC_ID_NONE was requested

Returns: 0 if OK, AVERROR_xxx on error

Definition at line 256 of file alsa.c.

Referenced by audio_read_header(), and audio_write_header().

◆ ff_alsa_close()

av_cold int ff_alsa_close ( AVFormatContext * s1 )

Close the ALSA PCM.

Parameters

s1	media file handle

Returns: 0

Definition at line 421 of file alsa.c.

◆ ff_alsa_xrun_recover()

int ff_alsa_xrun_recover	(	AVFormatContext *	s1,
		int	err )

Try to recover from ALSA buffer underrun.

Parameters

s1	media file handle
err	error code reported by the previous ALSA call

Returns: 0 if OK, AVERROR_xxx on error

Definition at line 437 of file alsa.c.

Referenced by audio_read_packet(), and audio_write_packet().

◆ ff_alsa_extend_reorder_buf()

int ff_alsa_extend_reorder_buf	(	AlsaData *	s,
		int	min_size )

Definition at line 460 of file alsa.c.

Referenced by audio_write_packet().

◆ ff_alsa_get_device_list()

int ff_alsa_get_device_list	(	AVDeviceInfoList *	device_list,
		snd_pcm_stream_t	stream_type )

Definition at line 477 of file alsa.c.

Referenced by audio_get_device_list(), and audio_get_device_list().

Variable Documentation

◆ alsa_chmap_table

alsa_chmap_table[]

Definition at line 133 of file alsa.c.

Referenced by alsa_chmap_pos_to_av_chan().

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ MAKE_REORDER_FUNC

◆ MAKE_REORDER_FUNCS

◆ FORMAT_I8

◆ FORMAT_I16

◆ FORMAT_I32

◆ FORMAT_F32

◆ PICK_REORDER

Function Documentation

◆ codec_id_to_pcm_format()

◆ MAKE_REORDER_FUNCS()

◆ alsa_chmap_pos_to_av_chan()

◆ alsa_get_chmap()

◆ find_reorder_func()

◆ ff_alsa_open()

◆ ff_alsa_close()

◆ ff_alsa_xrun_recover()

◆ ff_alsa_extend_reorder_buf()

◆ ff_alsa_get_device_list()

Variable Documentation

◆ alsa_chmap_table