[mythtv-users] PVR-350 TVout and no ALSA sound

Nick knowledgejunkie at gmail.com
Thu Jun 30 18:58:51 UTC 2005

On 6/30/05, Fedor Pikus <fpikus at gmail.com> wrote:
> I tried to change my Myth box to output TV using PRV350 TV-out instead
> of NVidia TVout.
> It works, except for this:
> As soon as I enable "Use PVR-350 MPEG2 decoder" in front-end, I don't
> get audio in MythTV. When MythTV starts, it says "Unable to initialize
> ALSA". In mythfrontend log, I get this message:
> Opening audio device 'default'.
> Rate doesn't match (requested 0Hz, got 4000Hz)
> Unable to set ALSA parameters
> Using the PVR-350 decoder/TV-out
> If I uncheck "Use PVR-350" and do NO OTHER CHANGES, MythTV initialized
> ALSA and plays sound just fine. I did not check "use PVR350 for audio"
> checkbox (if I do, I get no error message but no sound either, of
> course, since PVR350 audio outs are not connected to anything).
> In either case, MythMusic can play music with no problems. Mplayer can
> play to -ao alsa, so playing videos and DVDs also works. It's only
> MythTV that is affected, both for live TV and recording playback.
> MythTV is configured to use ALSA:default, ALSA 1.0.9, sound card is
> Audigy 2 ZS configured for digital out, simple asound.conf
> pcm.emu10k1 {
>    type hw
>    card 0
> }
> ctl.emu10k1 {
>    type hw
>    card 0
> }
> Seems like a bug in software, enabling PVR350 TVout should have no
> effect on audio card.

I thought that if you used the PVR-350's decoder, you couldn't choose
which parts of the stream it decodes (that's probably changed in the
latest release). Therefore, if you choose to use the decoder, it will
decode audio and video, not using the soundcard at all. Using
different devices for the streams could also introduce sync issues
which would need to be fixed.

The common way to set this up is to use a Y-cable to connect the 350
audio outs to the line-in of the soundcard. Select the line-in as the
recording source, set it to a sensible leve, mute it, and then
everything should work.

I'd also investigate why you don't get sound when you choose to use
the 350 to decode the audio. The lack of errors mean it is likely a
source is muted (but working).


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