[mythtv-users] Need help hacking a workaround for tinny audio with PVR-150

[John Biundo]

This problem seems to be outstanding (with ivtv) for a while now.  I 
believe it's again being actively investigated, but in the meantime, I'd 
like to develop a workaround.  I have an idea, but need help figuring 
out an implementation.

Right now, the tinny audio crops up on my 2nd PVR-150 card, say, about 
25% of the time.  This card is used during recordings, so I don't 
usually find out about the problem until playback, when it's too late. 
This is rather discouraging to my user community!

I've found that I can issue an ivtvctl -q0 command for this card and it 
has the curious effect of toggling the state of the audio between "good" 
(not tinny) and "bad" (tinny).  It succeeds somewhere close to 100% of 
the time toggling from bad to good.  Unfortunately, it *sometimes* 
toggles from good to bad (i.e. if I blindly issue the command without 
manually checking the state of the audio), though this seems to happen 
much less than 25% of the time.

So... if I can find a way to issue the ivtvctl command at the start of a 
  recording on this tuner, I should significantly reduce the likelihood 
of having the tinny audio.  I may, of course, still turn "good" to 
"bad", but the overall outcome should be better.

The question is, how would I go about doing that?  Is there a user-space 
"hook" in MythTV, or something I could bend to that purpose?

Thanks for any suggestion.

p.s. Many bonus points to anyone who can come up with a way to 
intelligently apply the command.  I.e., how might I programmatically 
test the state of the audio to detect "tinnyness"?