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ALSA: Define more channel map positions 

For following the standard, define more channel map positions and
shuffle the items a bit:

- As both PulseAudio and gstreamer define MONO channel position
  explicitly, we should follow that, too.  The mono streams point to
  this channel position unless they are explicitly assigned to certain
  channel positions.

- Top-front-* and Top-rear-* positions are added, carried from
  PulseAudio's definitions.

- Move NA and MONO definitions at the top of table right after
  UNKNOWN, since these are more abstract in comparison with other
  practical positions.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2012-09-12 18:06:54 +02:00
parent 0afdb8f286
commit 7b31d0095e
3 changed files with 23 additions and 9 deletions
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13
Documentation/sound/alsa/Channel-Mapping-API.txt
View File

@ -76,8 +76,10 @@ here is a cut:
/* channel positions */
enum {
/* this follows the alsa-lib mixer channel value + 1 */
SNDRV_CHMAP_UNKNOWN = 0,
SNDRV_CHMAP_NA, /* N/A, silent */
SNDRV_CHMAP_MONO, /* mono stream */
/* this follows the alsa-lib mixer channel value + 3 */
SNDRV_CHMAP_FL, /* front left */
SNDRV_CHMAP_FR, /* front right */
SNDRV_CHMAP_RL, /* rear left */
@ -98,8 +100,13 @@ enum {
SNDRV_CHMAP_FCH, /* front center high */
SNDRV_CHMAP_FRH, /* front right high */
SNDRV_CHMAP_TC, /* top center */
SNDRV_CHMAP_NA, /* N/A, silent */
SNDRV_CHMAP_LAST = SNDRV_CHMAP_NA,
SNDRV_CHMAP_TFL, /* top front left */
SNDRV_CHMAP_TFR, /* top front right */
SNDRV_CHMAP_TFC, /* top front center */
SNDRV_CHMAP_TRL, /* top rear left */
SNDRV_CHMAP_TRR, /* top rear right */
SNDRV_CHMAP_TRC, /* top rear center */
SNDRV_CHMAP_LAST = SNDRV_CHMAP_TRC,
};
When a PCM stream can provide more than one channel map, you can

13
include/sound/asound.h
View File

@ -474,8 +474,10 @@ enum {
/* channel positions */
enum {
/* this follows the alsa-lib mixer channel value + 1 */
SNDRV_CHMAP_UNKNOWN = 0,
SNDRV_CHMAP_NA, /* N/A, silent */
SNDRV_CHMAP_MONO, /* mono stream */
/* this follows the alsa-lib mixer channel value + 3 */
SNDRV_CHMAP_FL, /* front left */
SNDRV_CHMAP_FR, /* front right */
SNDRV_CHMAP_RL, /* rear left */
@ -496,8 +498,13 @@ enum {
SNDRV_CHMAP_FCH, /* front center high */
SNDRV_CHMAP_FRH, /* front right high */
SNDRV_CHMAP_TC, /* top center */
SNDRV_CHMAP_NA, /* N/A, silent */
SNDRV_CHMAP_LAST = SNDRV_CHMAP_NA,
SNDRV_CHMAP_TFL, /* top front left */
SNDRV_CHMAP_TFR, /* top front right */
SNDRV_CHMAP_TFC, /* top front center */
SNDRV_CHMAP_TRL, /* top rear left */
SNDRV_CHMAP_TRR, /* top rear right */
SNDRV_CHMAP_TRC, /* top rear center */
SNDRV_CHMAP_LAST = SNDRV_CHMAP_TRC,
};
#define SNDRV_CHMAP_POSITION_MASK 0xffff

6
sound/pci/ctxfi/ctpcm.c
View File

@ -397,7 +397,7 @@ static struct snd_pcm_ops ct_pcm_capture_ops = {
static const struct snd_pcm_chmap_elem surround_map[] = {
{ .channels = 1,
.map = { SNDRV_CHMAP_UNKNOWN } },
.map = { SNDRV_CHMAP_MONO } },
{ .channels = 2,
.map = { SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
{ }
@ -405,7 +405,7 @@ static const struct snd_pcm_chmap_elem surround_map[] = {
static const struct snd_pcm_chmap_elem clfe_map[] = {
{ .channels = 1,
.map = { SNDRV_CHMAP_UNKNOWN } },
.map = { SNDRV_CHMAP_MONO } },
{ .channels = 2,
.map = { SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE } },
{ }
@ -413,7 +413,7 @@ static const struct snd_pcm_chmap_elem clfe_map[] = {
static const struct snd_pcm_chmap_elem side_map[] = {
{ .channels = 1,
.map = { SNDRV_CHMAP_UNKNOWN } },
.map = { SNDRV_CHMAP_MONO } },
{ .channels = 2,
.map = { SNDRV_CHMAP_SL, SNDRV_CHMAP_SR } },
{ }