[alsa-devel] PS3 - Surround sound on SPDIF set-up

[Takashi Iwai]

At Mon, 02 Jul 2007 19:17:35 -0700,
gt bradley wrote:
> 
> Hi,
> I've been beating my had against this for several weeks now.  (started
> with fedora 6, tried adding in the plugings etc (version 1.0.12) -- also
> tried upgrading to the current 1.0.14 version, without success (couldn't
> produce surround-sound on teh spdif output).  I have now switched to
> fedorea 7 and was able to have rythmbox play surround sound via spdif,
> but have since lost that ability.  (but I'm convinced the hardware and
> low-level drivers support it).  In order to limit the number of moving
> parts, I have reduced to just trying to get speaker-test to play on all
> 6 speakers.

SPDIF is basically only for a two-channel PCM stream.  For 5.1
outputs, you'll have to encode the raw multi-channel PCM to some
compressed format such as AC3 or DTS and embed in SPDIF frames.
And, that's not the driver job, so far -- at least the current driver
doesn't do any conversion.  Thus a software has to do it.

You can try a52 plugin for the on-the-fly encoding, found in
alsa-plugins package.  The plugin seems working for some apps but for
some not yet well, unfortunately...


Takashi