[mythtv-users] Stereo sound with PVR-250

[Joseph A. Caputo]

Note: please don't top-post.  See below.

On Friday 15 October 2004 17:28, Mats Cedergren wrote:
> From: Joseph A. Caputo [mailto:jcaputo1 at comcast.net]
> > Sent: Fri 10/15/2004 11:01 PM
> > To: Discussion about mythtv
> > Subject: Re: [mythtv-users] Stereo sound with PVR-250
> >
> > On Friday 15 October 2004 15:39, Mats Cedergren wrote:
> > > Is anybody getting stereo sound with there PVR-250 cards under
> > > linux? I only get mono :(
> >
> > What are you recording from?  Tuner or A/V in?  If you're recording
> > from the tuner, then the problem is probably your audio output, not
> > the -250.  If the -250 is really recording mono sound and the source
> > is definitely stereo, then you've got a bad card.
> >
> > More likely, either (1) you've misconfigured your tuner type, (1a) 
or
> > if you're not using the tuner, does your audio input to the PVR-250
> > have a stereo plug?, or (3) your recordings are just fine, but there
> > is a problem with the way your audio output is configured, which has
> > nothing to do with the PVR-250.  To check (3), try playing a
> > recording on a different machine.
> >
> > -JAC
>
> 
> I'm recordning from the Tuner. I have tried the same card in
> WindowsXP (the same computer, dual boot setup) and there the card
> works perfectly and I get stereo sound from all channels that
> transmit in stereo.
>
> I have not tried the recordning on another computer yet, will try
> that tomorrow, but I don't think that it will make any difference.
> When I play music or other movies (.avi, .mpg, dvd etc) i get stereo
> sound.

When you play them with what?  Myth's internal player?  I assume you're 
playing them with other programs (mplayer, xine, etc).  So all that 
tells us is that there's nothing wrong with your sound card or driver.

Now we need to make sure that Myth is properly configured for sound 
output.  The best way to do this is to take a known good file (like a 
'good' .avi or .mpg file with stereo sound) and play it using Myth's 
internal player with the command "mythtv <filename>".  If you get 
stereo sound here (and I bet you will), then your sound output is 
configured properly within Myth.

> When I play a video captured with "cat /dev/video0 > /tmp/test.mpg"
> using mplayer "mplayer /tmp/test.mpg" it reports that the file have
> two channel sound but I can hear that the sound is not in stereo.

This sounds like there's a problem with your ivtv driver setup, or with 
your input source.  Since you say you've rebooted the same setup into 
Windows and heard stereo, I'm guessing that your input source is OK.  
Therefore I'm guessing there is some problem with your ivtv driver 
setup.  Try playing with the test_ioctl program to query/change the 
capture settings for your card (you'll probably need to quit 
mythbackend to do this).  Specifically, look at the "-A" option, which 
sets the audio capture mode to Mono, Stereo, Lang2/SAP or Lang1.  I'm 
afraid this is a bit out of my area of expertise; I suppose it's 
possible that something is putting your card in Mono capture mode; 
perhaps your card is being mis-identified by the ivtv driver; in that 
case, you might need to pass some parameters to the driver via the /
etc/modules.conf file.  You might want to ask on the ivtv-users list; 
make sure to have the specific specs of your card handy (i.e., the 
output of "lspci").

HTH,

JAC