[mythtv-users] Not a newbie, need help with sound recording please, wit's end...

[Larry Silverman]

Hi, all.

I've got a 2-tuner system, one PVR-250 recording perfectly, and one
obstinate bt878-based card.  I'm running Fedora Core 3 
2.6.10-1.741_FC3.  I've also tried the 681 release, but it seems those
rpms have been pulled for ivtv, so I had to upgrade.

I've followed Jarod's excellent guide, but I seem to be stuck on
piping the audio from the bt878 and recording it in MythTV.  I have 4,
count 'em, 4 different sound cards, one of which is brand new, just
arrived.  The others were a little old, and ALSA support was sketchy. 
I thought this new one would be the answer.

The mixers are all set correctly.  I'm very confident I know what I'm
doing in this regard.  I ran the line-out from the bt878 to the Aux
input on the soundcard.  I successfully get audio using xawtv and
unmuting the Aux line.  This works on all my sound cards.  What
doesn't work is capture.

I'm using the new card now.  When I mute Aux and enable Capture for
Aux, aplay /dev/dsp gives this:

Playing raw data '/dev/dsp' : Unsigned 8 bit, Rate 8000 Hz, Mono
underrun!!! (at least 15.238 ms long)
underrun!!! (at least 15.337 ms long)
underrun!!! (at least 15.483 ms long)
underrun!!! (at least 15.460 ms long)
underrun!!! (at least 15.460 ms long)
underrun!!! (at least 15.460 ms long)

I actually do hear the TV, but it sounds cruddy, naturally, at 8-bit 8khz mono.

In MythTV, I get no sound.  In mythtvsetup, the tuner is correctly set
up to capture on /dev/dsp.  There are no other /dev/dsp's in my /dev
directory.  There are no other sound devices in /dev that work with
aplay (I've tried all the following devices: /dev/adsp, /dev/sound,
and several files in /dev/snd - controlC0  pcmC0D0c   pcmC0D0p  
pcmC0D1p   pcmC0D2c   pcmC0D2p   timer, none work the way /dev/dsp
does).  My bt878 doesn't seem to support btaudio or snd_bt87x drivers,
so line-out is the only option.

Stumbling around google and the forums, I found reference to a sox
command.  Lo and behold, when I the following while using xawtv:
# sox -w -r 44000 -t ossdsp /dev/dsp -t ossdsp /dev/dsp
I get MUCH better audio.  It's not perfect, however, because it has
little pops in it.

I don't know why MythTV has no audio.  I don't know why aplay /dev/dsp
always gives me back 8 bit, 8kHz audio.

This sounds foolish, but is there a way to make MythTV change its
sample rate or maybe record through sox (gag)?

Please, please, someone help me out on this.  I know a lot of other
people are having this exact same problem.

Thanks,

Larry