[mythtv-users] How to debug "no sound" ?

[John P Poet]

I just did a fresh install of Fedora Core 4.  Everything is working great, except I get no sound out of Myth.

I had a similar problem when I first installed my maudio sound card under FC2.  All "other" programs would produce sound out the S/PDIF jack just fine, but Myth was mute.  I thought I had finally figured out what needed to go into my asound.conf file, to make Myth happy.  I have tried using that exact same asound.conf file under FC4, but Myth is still silent.

What is weird, is that mplayer works with the S/PDIF out perfectly, even when a asound.conf file does not exist.  All I have to do is use "mplayer -ao alsa -ac hwac3" and it just works.

Xine and aplay require the asound.conf file, however.  For Xine and aplay, this asound.conf file is sufficient:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pcm.!default {
  type plug
  slave.pcm iec958
}

pcm.ice1712 {
   type hw
   card 0
   device 0
}

ctl.ice1712 {
   type hw
   card 0
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

With the above asound.conf, I can play both AC3 and stereo material via the S/PDIF port using any program *except* Myth.

Under FC2, I thought I had solved the problem by adding:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pcm.ice1712_spdif {
    type plug
    ttable.0.8 1 # S/PDIF left...Delta 9
    ttable.1.9 1 # S/PDIF right...Delta 10
    slave.pcm ice1712
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

And then telling Myth to use "ALSA:ice1712_spdif".  However, that does not seem to be working under FC4.  I end up with this in my log:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2005-06-25 21:03:39.653 Using protocol version 17
adding pes stream at pid 0x31 with type 2
adding pes stream at pid 0x34 with type 129
2005-06-25 21:03:42.696 libavformat type mpegts
0: start_time: 4752.137 duration: 323.408
1: start_time: 4752.094 duration: 323.407
stream: start_time: 52801.048 duration: 3593.896 bitrate=15577 kb/s
2005-06-25 21:03:43.472 Stream #1 (audio track #0) is an audio stream with 2 channels.
2005-06-25 21:03:43.472 Auto-selecting AC3 audio track (stream #1).
2005-06-25 21:03:43.472 Initializing audio parms from audio track #0.
2005-06-25 21:03:43.603 Killing AudioOutputDSP
2005-06-25 21:03:43.604 Opening audio device 'ice1712_spdif'.
2005-06-25 21:03:43.612 in SetParameters(format=2, channels=2, rate=48000, buffer_time=500000, period_time=125000)
2005-06-25 21:03:43.613 get_buffer_size returned 6553
2005-06-25 21:03:43.613 set_period_time_near returned 68250
2005-06-25 21:03:43.613 get_period_size returned 3276
2005-06-25 21:03:43.621 Audio fragment size: 4096
2005-06-25 21:03:43.623 Audio Stretch Factor: 1
2005-06-25 21:03:43.623 Ending reconfigure
2005-06-25 21:03:43.624 kickoffOutputAudioLoop: pid = 13790
2005-06-25 21:03:43.624 OutputAudioLoop: Play Event
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I am not even sure the problem has anything to do with the S/PDIF port.  Using the envy24control utility, I see that when Myth is "playing", no audio is being generated on *any* of the soundcard's jacks.  When I use mplayer,xine or aplay, the envy24control utility shows me that audio is being routed to the S/PDIF jack.  If I remove the asound.conf file, and use aplay, envy24control shows me that the audio is being routed to the first two analog jacks.

So, how do I debug this?  How can I figure out why all other programs will send sound to my audio card, but Myth is mute?  Since Myth is not generating any errors, I have no idea where to look.

Thanks,

John

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