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ALSA: implement channel layout for playback.

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Currently, only S16 quad, 5.1 and 7.1 are implemented.
Implementing support for other formats/layouts and capture should be
straightforward.

7.1 support by Carl Eugen Hoyos.
This commit is contained in:
Nicolas George 2011-03-10 12:10:34 +01:00
parent 98ac192b4e
commit 813dbb4442
3 changed files with 106 additions and 1 deletions
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90
libavdevice/alsa-audio-common.c
View File

@ -43,6 +43,59 @@ static av_cold snd_pcm_format_t codec_id_to_pcm_format(int codec_id)
}
}
static void alsa_reorder_s16_out_51(const void *in_v, void *out_v, int n)
{
const int16_t *in = in_v;
int16_t *out = out_v;
while (n-- > 0) {
out[0] = in[0];
out[1] = in[1];
out[2] = in[4];
out[3] = in[5];
out[4] = in[2];
out[5] = in[3];
in += 6;
out += 6;
}
}
static void alsa_reorder_s16_out_71(const void *in_v, void *out_v, int n)
{
const int16_t *in = in_v;
int16_t *out = out_v;
while (n-- > 0) {
out[0] = in[0];
out[1] = in[1];
out[2] = in[4];
out[3] = in[5];
out[4] = in[2];
out[5] = in[3];
out[6] = in[6];
out[7] = in[7];
in += 8;
out += 8;
}
}
#define REORDER_DUMMY ((void *)1)
static av_cold ff_reorder_func find_reorder_func(int codec_id,
int64_t layout,
int out)
{
return
codec_id == CODEC_ID_PCM_S16LE || codec_id == CODEC_ID_PCM_S16BE ?
layout == AV_CH_LAYOUT_QUAD ? REORDER_DUMMY :
layout == AV_CH_LAYOUT_5POINT1_BACK ?
out ? alsa_reorder_s16_out_51 : NULL :
layout == AV_CH_LAYOUT_7POINT1 ?
out ? alsa_reorder_s16_out_71 : NULL :
NULL :
NULL;
}
av_cold int ff_alsa_open(AVFormatContext *ctx, snd_pcm_stream_t mode,
unsigned int *sample_rate,
int channels, enum CodecID *codec_id)
@ -54,6 +107,7 @@ av_cold int ff_alsa_open(AVFormatContext *ctx, snd_pcm_stream_t mode,
snd_pcm_t *h;
snd_pcm_hw_params_t *hw_params;
snd_pcm_uframes_t buffer_size, period_size;
int64_t layout = ctx->streams[0]->codec->channel_layout;
if (ctx->filename[0] == 0) audio_device = "default";
else audio_device = ctx->filename;
@ -146,6 +200,26 @@ av_cold int ff_alsa_open(AVFormatContext *ctx, snd_pcm_stream_t mode,
snd_pcm_hw_params_free(hw_params);
if (channels > 2 && layout) {
s->reorder_func = find_reorder_func(*codec_id, layout,
mode == SND_PCM_STREAM_PLAYBACK);
if (s->reorder_func == REORDER_DUMMY) {
s->reorder_func = NULL;
} else if (s->reorder_func) {
s->reorder_buf_size = buffer_size;
s->reorder_buf = av_malloc(s->reorder_buf_size * s->frame_size);
if (!s->reorder_buf)
goto fail1;
} else {
char name[16];
av_get_channel_layout_string(name, sizeof(name), channels, layout);
av_log(ctx, AV_LOG_WARNING,
"ALSA channel layout unknown or unimplemented for %s %s.\n",
name,
mode == SND_PCM_STREAM_PLAYBACK ? "playback" : "capture");
}
}
s->h = h;
return 0;
@ -160,6 +234,7 @@ av_cold int ff_alsa_close(AVFormatContext *s1)
{
AlsaData *s = s1->priv_data;
av_freep(s->reorder_buf);
snd_pcm_close(s->h);
return 0;
}
@ -184,3 +259,18 @@ int ff_alsa_xrun_recover(AVFormatContext *s1, int err)
}
return err;
}
int ff_alsa_extend_reorder_buf(AlsaData *s, int min_size)
{
int size = s->reorder_buf_size;
void *r;
while (size < min_size)
size *= 2;
r = av_realloc(s->reorder_buf, size * s->frame_size);
if (!r)
return AVERROR(ENOMEM);
s->reorder_buf = r;
s->reorder_buf_size = size;
return 0;
}

10
libavdevice/alsa-audio-enc.c
View File

@ -76,7 +76,15 @@ static int audio_write_packet(AVFormatContext *s1, AVPacket *pkt)
int size = pkt->size;
uint8_t *buf = pkt->data;
while((res = snd_pcm_writei(s->h, buf, size / s->frame_size)) < 0) {
size /= s->frame_size;
if (s->reorder_func) {
if (size > s->reorder_buf_size)
if (ff_alsa_extend_reorder_buf(s, size))
return AVERROR(ENOMEM);
s->reorder_func(buf, s->reorder_buf, size);
buf = s->reorder_buf;
}
while ((res = snd_pcm_writei(s->h, buf, size)) < 0) {
if (res == -EAGAIN) {
return AVERROR(EAGAIN);

7
libavdevice/alsa-audio.h
View File

@ -39,10 +39,15 @@
other formats */
#define DEFAULT_CODEC_ID AV_NE(CODEC_ID_PCM_S16BE, CODEC_ID_PCM_S16LE)
typedef void (*ff_reorder_func)(const void *, void *, int);
typedef struct {
snd_pcm_t *h;
int frame_size; ///< preferred size for reads and writes
int period_size; ///< bytes per sample * channels
ff_reorder_func reorder_func;
void *reorder_buf;
int reorder_buf_size; ///< in frames
} AlsaData;
/**
@ -82,4 +87,6 @@ int ff_alsa_close(AVFormatContext *s1);
*/
int ff_alsa_xrun_recover(AVFormatContext *s1, int err);
int ff_alsa_extend_reorder_buf(AlsaData *s, int size);
#endif /* AVDEVICE_ALSA_AUDIO_H */