[mythtv-users] Alsa SPDIF NForce4

[Scott Alfter]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Timothy Bish wrote:
> Need a little help getting ALSA to output everything to SPDIF, currently I
> get nothing.

After having tried previously and given up, I gave onboard S/PDIF another shot
last night.  I updated the kernel to the latest and greatest and went over some
of the other messages in this thread.

Try the following:

1) Delete /etc/asound.conf, if present...you don't need it.
2) In alsamixer, make sure these settings are as follows:
   IEC958: unmuted
   IEC958 Playback AC97-SPSA: 0%
   IEC958 Playback Source: PCM
   PCM: unmuted (level shouldn't matter, but mine is at 77%)
   Master: unmuted (level shouldn't matter, but mine is at 77%)
3) Test PCM audio:
   aplay /dev/urandom
   You should get white noise.
4) Test AC3 passthrough:
   mplayer -ao alsa -ac hwac3, dvd://

One annoyance I found while watching something with an AC3 soundtrack last
night was that in one hour, the stream glitched somehow and was interrupted a
couple or three times.  With my receiver, that translates to a couple of
seconds of silence as it switches from AC3 to PCM mode and back to AC3 mode.  I
had the MythTV audio device set to ALSA:default, but I'm going to try again
with it set to /dev/dsp.  That should go through kernel-space OSS emulation.
If it plays an hour or two without the receiver doing weird things, I'll
consider my nForce S/PDIF problems fixed.  If not, I'll just switch back to the
USB S/PDIF dongle I've been using and forget that I have an onboard output. :-P

(I had this same occasional AC3 dropout problem with the nForce2 I was using
previously, and had never figured out a fix for it.)

  _/_
 / v \ Scott Alfter
(IIGS( http://alfter.us/            Top-posting!
 \_^_/ rm -rf /bin/laden            >What's the most annoying thing on Usenet?

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2.1 (Cygwin)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFE4RNPVgTKos01OwkRAvjuAJ9CrkJn/fshZ+mYwNN4r0aly8haPQCg0F+g
Az314U0wz57tf1m/ClfehqQ=
=bHsH
-----END PGP SIGNATURE-----