[mythtv] PVR-350 and 44100 audio capture rate

Jim Brunner jim.brunner at comcast.net
Fri Feb 6 23:18:58 EST 2004


Greetings, I've been struggling with audio for about a week now.  
Making progress, but now I'm stumped.

I'm using a PVR-350 for input, but using software decoding for output 
through the graphics card.  For audio out, I'm routing the audio out 
S/PDIF to my HT amp.  Unfortunately, my amp only supports digital rates 
of 44100 Hz.  The PVR-350 defaults to 48000.

So, after mucking with the IVTV code for a while, I've managed to force 
it into 44100 mode.  (The PVR-350 hardware does support 44100 audio 
capture.)

I can now do "cat /dev/video0 >test.mpg" and then "mplayer test.mpg" 
and I get audio and video.  (Note that there are several options for 
mplayer in the mplayer conf file.)

However, when I launch mythfrontend and go to live TV, I get no audio.  
The text output which is visible after quitting the front end indicates 
that the audio rate is still 48000.

I thought I had totally crippled IVTV so that it could only use 44100, 
but apparently not.

I've tried setting the max audio frequency on the mythbackend settings, 
but that doesn't appear to do anything.  Does that have any affect if 
you choose PVR-350 as the input?

BTW - I'm not using the PCR-350 for output because I want to add a 
pcHDTV card eventually.  I could probably get analog out to work, but 
would prefer digital.

I've tried searching the mythtv code for places where it could be 
setting the audio frequency, but I haven't found anything obvious.  
What am I missing here?  Any help would be appreciated - I'm starting 
to bruise my forehead from all of the wallbanging.



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