[alsa-devel] Surround and SPDIF on STAC9277

[Jon Smirl]

On 5/26/08, Takashi Iwai <tiwai at suse.de> wrote:
> At Sat, 24 May 2008 17:02:21 -0400,
>
> Jon Smirl wrote:
>  >
>  > I've figure out that the answer that I'm looking for is AC3 over SPDIF
>  > support. Now I'm trying to figure out how to make it work in pulse.
>
>
> If you think of real-time conversion to AC3 from linear PCM streams, I
>  guess pulseaudio doesn't support it natively.

mesilliac has got it to work. There are instructions here using the a52 plugin.
http://ubuntuforums.org/showthread.php?p=4451132

I'm running it right now on Ubuntu 64b. Flash works.

It has some issues:
 sound from VLC is broken up
 mplayer works when it uses surround51 but not with AC3 pass-through
 my stereo music is getting copied to all six channels which messes up
the processing the amp.

Getting this to work simply and reliably would be a nice feature. I
suspect most people who run SPDIF to their stereo don't realize that
they are only getting a stereo signal and they need to use something
like a52.


>
>
>  Takashi
>
>
>
>  > On 5/24/08, Jon Smirl <jonsmirl at gmail.com> wrote:
>  > > How are you supposed to get 5.1 audio out of your PC? When I hook the
>  > >  SPDIF device from my STAC9227/HDA audio up to pulse, pulse says that
>  > >  the SPDIF channel only supports stereo.
>  > >
>  > >  So I go digging around the in STAC9227 datasheet.
>  > >  http://www.idt.com/?genID=STAC9227
>  > >
>  > >  STAC9227 codec only supports 192Khz SPDIF with 4/1*48Khz channels. It
>  > >  doesn't support 384Khz with 8/1*48Khz channels.
>  > >
>  > >  So there are two problems, first the existing Intel HDA/STAC9227
>  > >  driver is not exposing the 4 channel SPDIF support. Or I can't figure
>  > >  out how to get to it.
>  > >
>  > >  Second, the hardware doesn't seem to support any way to get digital
>  > >  5.1 audio out of the codec and into my Sony amp. STAC9227 does have
>  > >  six channel analog out, but my Sony amp doesn't have 6 channel analog
>  > >  in. Sony amp supports 384Khz 8-channel SPDIF in.
>  > >
>  > >
>  > >  --
>  > >  Jon Smirl
>  > >  jonsmirl at gmail.com
>  > >
>  >
>  >
>  > --
>  > Jon Smirl
>  > jonsmirl at gmail.com
>
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>  >
>


-- 
Jon Smirl
jonsmirl at gmail.com