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| author | Takashi Iwai <tiwai@suse.de> | 2012-09-12 18:06:54 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2012-09-12 18:13:03 +0200 |
| commit | 7b31d0095e87221dc32c95642a2a714ea08259aa (patch) | |
| tree | 098dc2c137b0f9a0d098d6e7751ab350e027cd6e /Documentation/sound | |
| parent | 0afdb8f2869610b7c2eb99d75ba8b9003b8e88d7 (diff) | |
| download | lwn-7b31d0095e87221dc32c95642a2a714ea08259aa.tar.gz lwn-7b31d0095e87221dc32c95642a2a714ea08259aa.zip | |
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>
Diffstat (limited to 'Documentation/sound')
| -rw-r--r-- | Documentation/sound/alsa/Channel-Mapping-API.txt | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/Documentation/sound/alsa/Channel-Mapping-API.txt b/Documentation/sound/alsa/Channel-Mapping-API.txt index 4bbf12d5553f..3c43d1a4ca0e 100644 --- a/Documentation/sound/alsa/Channel-Mapping-API.txt +++ b/Documentation/sound/alsa/Channel-Mapping-API.txt @@ -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 |