[alsa-devel] Required/preferred multichannel order for ALSA
ricardo.neri at ti.com
Thu Apr 26 23:33:57 CEST 2012
Hi Takashi, list,
I am implementing multichannel support for HDMI on Texas Instruments'
OMAP4. I would like to know if ALSA mandates a specific channel order or
has a preferred one.
I tried to find some guidance in alsa-lib or in the alsa driver. All I
could find is the order described in speaker-test:
FL/FR/RL/RR/C/LFE/SL/SR. This order seems to be in use due to historical
reasons . It was also mentioned that an API to set/get the channel
mapping was going to be implemented ; I tried to find it without
success. As  and  are very old posts, I was wondering if the
situation has changed.
My question arises from the fact that HDMI audio uses the channel
ordering defined in CEA-861 section 6.6.2, which is different from what
speaker-test expects. This also different from the order that SMPTE 320M
specifies. OMAP4 is able to alter the channel mapping, so I could match
what ALSA expects if such required/preferred order exists.
Thanks in advance for your comments.
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