[mythtv-users] Myth/spdif no audio, mplayer works fine

John Patrick Poet john at BlueSkyTours.com
Tue Mar 29 07:29:52 UTC 2005


I know this subject has been hashed to death.  I have spent the last 5 
hours doing searches trying to figure out how to fix it.

I was using an old SoundBlaster Live! card, and everything worked fine.  
I just exchanged that card for a M-AUDIO Delta 410.  Configure ALSA to 
drive it, and tested with aplay and mplayer.  Everything worked beautifully.

Then I tried Myth.  Myth seems to "open" the sound card just fine.  It 
even seems to write to it just fine:

2005-03-29 00:14:40.933 audio waiting for space on soundcard: have 1416 
need 4096
2005-03-29 00:14:40.940 audio waiting for space on soundcard: have 2756 
need 4096
2005-03-29 00:14:40.947 Broadcasting free space avail
2005-03-29 00:14:40.947 WriteAudio: Preparing 4096 bytes (1024 frames)
2005-03-29 00:14:40.948 audio waiting for space on soundcard: have 80 
need 4096
2005-03-29 00:14:40.951 _AddSamples bytes=6144, used=88065, free=423935, 
timecode=3271830
2005-03-29 00:14:40.952 _AddSamples bytes=6144, used=94209, free=417791, 
timecode=3271862
2005-03-29 00:14:40.954 audio waiting for space on soundcard: have 1352 
need 4096
2005-03-29 00:14:40.961 audio waiting for space on soundcard: have 2692 
need 4096
2005-03-29 00:14:40.968 audio waiting for space on soundcard: have 4036 
need 4096
2005-03-29 00:14:40.975 Broadcasting free space avail

But I go no sound whatsoever!

I know the S/PDIF port is working because I can use mplayer to play both 
files which just have a mp2 audio track, and files which have DD2.0 
audio tracks.  I can use aplay to play wav files.  Everything works 
except Myth.

I have AC3 passthrough turned on, and currently have ALSA:iec958 in the 
driver box.  I have also tried ALSA:default, and I have even tried 
ALSA:cards.pcm.iec958.  Myth does not complain about any of those 
setting, it just doesn't work.

If I bring up envy24control (a fancy mixer specifically for the ice17xx 
sound cards), I can watch the S/PDIF output levels dance when I use 
mplayer or aplay.  None of the levels dance when Myth is playing -- not 
even the analog levels.  Even though Myth does not complain, and seems 
to think it is sending data to the audio card, it looks like the sound 
card driver is not receiving the data.

I have tried rebooting a few times.  I have tried playing with the 
/etc/asound.conf file.  I am out of ideas.

Anyone else seen anything like this?

Thanks,

John





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