[mythtv-users] problems with AC3 passthrough

[myth at najdrovsky.com]

Hi all, first time poster here, but have been browsing the archives for a
while.    I've got my HDTV myth set up almost working, but I've not been able
to get the AC3 passthrough to work.  If I disable it, I get PCM audio through
the S/PDIF port and hear it through my stereo, but it's choppy since the
computer has to decode both HighDef video and the AC3 stream.   What this
does, at least, is confirm that I'm able to reach the digital output connector
and send out the data.  Unfortunately, when I check off the passthrough, the
AC3 stream appears to be sent for a split second, and then it's nothing but
silence.  The reason I know that the first few bits of the AC3 stream make it
through is because I hear a split second of audio, and my receiver's display
lights up the AC3 letters.

My configuration is as follows:
Hardware:
* Chaintech 7NIF2 motherboard with the optional S/PDIF I/O bracket. This board
  uses the nVidia nForce2 chipset and also has the CMedia 9738 sound chip,
  which appars to be intel8x0 compatible.

* pcHDTV hidef tuner card
* ALSA 1.0.2

The audio output device in myth is configured to    ALSA:hw:0,2

Could someone please provide some suggestions as to what I need to do to get
the AC3 stream to work correctly?  BTW, please don't tell me to switch to OSS,
because I don't get any sound at all via OSS.

thanks,
 Bo Najdrovsky

p.s.  Here is a tip for those with HDTV sets,  nVidia's 1.0-5610 video driver
supports interlaced video, so I'm able to get a nice 59.97Hz 1920x1080i video
output on my high def TV. The video overlay works fine in this high resolution
also.