Re: [xine-user] AC3 SPDIF USB Audio

[James Courtier-D. <Ja...@su...>]

af...@ad... wrote:
> Hello,
> First let me say Xine is a great piece of software (IMHO), and I've been using it for about a year with MythTV.
> 
> Currently, I am trying to get SPDIF optical output working with Xine and playing DVDs.  I've downloaded the latest version of Xine-lib, compiled and am able to run it.  Here's the problem:
> 
> I am using a Sound Blaster Live! 24 bit external (USB) sound board.  SPDIF passthrough works perfectly for DTS audio, but not Dolby Digital (5.1) AC3 signals.  I can verify DTS on my sony receiver when connected and having chosen the correct audio channel.  This works with both ALSA and OSS.  When I use Dolby Digital, there is no volume.  When I connect to an Alpine DSP, it flashes Dolby Digital, then goes back to pro-logic without any sound.  I have configured Xine to use the passthrough, but have not changed the iec958:AES0... device line.
> 
> My thought is somewhere the header for DD is sent, but the rest of the packets are not.  I have liba52 compiled and loaded on the machine.  Is it possible to disable liba52 in Xine?  Could Xine be misdirecting information to liba52 or is there a command line option I missed (-s)?  Is this possibly the problem?  I am thinking Alsa and the hardware are okay since DTS seems to work fine.  Also, all other audio options work fine to the external board (5.1, 5.0, 2.0, etc) using the individual analog channels, but my needs are to send AC3 data to my DSP.  Is there a good way to maybe strip the AC3 channel from a movie (mpegdec) and cat it directly to the sound board without using a full fledged dvd player (cat sound.ac3 > /dev/dsp)?  This would allow me to test the hardware and probably Alsa, right?
> 
> Any help is greatly appreciated. I am running RH9, Alsa 1.0.3 (i think) from source, Xine 1.0.1 from source, xineui 0.99.3 from source.  Has anyone else seen this problem?  Please let me know if more information is necessary.
> 
> 

AC3 requires a special bit on the SPDIF port to be set. This is the
"non-audio" bit.
I don't think anyone in opensource has worked out how to set this bit on
USB sound cards yet.
If I get a moment, I might give it a try. I have an USB Audigy2 NX.

James