[mythtv-users] Re:btaudio works under sox but not MythTV

NICHOLAS ALLEN HALL nhall at students.wisc.edu
Thu Jul 31 16:59:50 EDT 2003


----- Original Message -----
From: "Joseph A. Caputo" <jcaputo1 at comcast.net>
Date: Monday, July 28, 2003 12:12 pm
Subject: RE: [mythtv-users] Re:btaudio works under sox but not MythTV

> > -----Original Message-----
> > From: mythtv-users-bounces at snowman.net
> > [mythtv-users-bounces at snowman.net]On Behalf Of NICHOLAS ALLEN
> > HALL
> > Sent: Sunday, July 27, 2003 3:18 PM
> > To: mythtv-users at snowman.net
> > Subject: Re: [mythtv-users] Re:btaudio works under sox but not 
> MythTV>
> >
> > Thanks for the help everyone. I feel stupid but at least got
> > btaudio to function by changing the capture card to use /dev/dsp1
> > (my digital capture device) as suggested by several people. Now I
> > have a related problem however:
> >
> > When I go to watch TV, the audio comes out high-pitched, like a
> > chipmunk. Now, I've searched the MythTV mailing list trying to
> > figure out how to fix this and have tried everything previously
> > posted but have not gotten it working yet. I realize it has
> > something to do with the sampling rate. This is how I have it 
> set up:
> >
> > In MythTV's "setup" program, in the capture card setting
> > underneath where I set /dev/dsp1, I have Audio sampling rate
> > limit set to 32000, which I believe should be what my capture
> > card returns audio at. I've also checked the mythconverg database
> > and that value is in there properly. I've tried changing this but
> > all settings result in a high pitch (although higher ones seem to
> > make the audio even higher pitched).
> >
> > In the mythfrontend TV recording setup, the sampling rate is set
> > to 32000. I've tried changing it to other settings but they do 
> not help.
> >
> 
> Did you change the sampling rate for both the 'Default' and 'LiveTV'
> recording profiles?
> 
> -JAC
> 
> 


Thanks for replying. Yes, I changed the sampling rate to 32000 for both the Default and LiveTV recording profiles. Even though it says on that screen that 32000 is recommended for btaudio, I did also try changing them both to 48000 after I was unable to get the sound to the normal pitch at 32000 but it did not help - no matter what they are set to the high-pitch chipmunk sound still remains. 

One note that may or not be significant is that when I'm watching live tv, the video is the normal speed but since the sound seems about 2 times faster, the sound pauses every couple seconds to let the video catch up (I think this seems obvious). However, if I record a program, the sound is still the same speed/pitch but the audio is also speeded up and stays in sync with the video. I used MythTV to do a 1 minute "manual recording" and then played back the video it recorded and it took 38 seconds to play the video so it turns out that the video plays at about 1.6x normal speed.

I was curious what would happen if I changed the mythfrontend Record options for "Default" and "LiveTV" to 48000 kHz and the video still recorded so it played in 38 seconds, with no apparent difference. I've also tried changing the "setup" settings for the capture card to have a sampling rate limit of "none" and also tried "48000" (in addition to the 32000 it apparently should be) and all of those settings always result in a recording of 38 seconds long, so it doesn't seem like any of those settings are actually doing anything. I've checked the "capturecard" table in the mythconverg to confirm that the setup program is definitely putting the values in there.

Does anyone have any suggestions of where to look next? Thanks for any help,

Nick



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