[mythtv-users] Upgrade and problems with 32kHz audio

[Michael T. Dean]

On 03/07/2009 11:47 AM, Norm Dugas wrote:
> Ray wrote:
>> I recently upgraded to the latest Mythtv version and I'm having 
>> problems with some of my older recordings that were recorded with an 
>> audio sampling rate of 32000 Hz.  These are Mpeg4 files from a bt878 
>> card and probably using btaudio (they were recorded back in 2003 & 
>> 2004).  The videos play fast and the audio sounds like chipmunks.  My 
>> recent recordings done with a PVR-500 card play just fine.  I tried 
>> transcoding one of these problem videos with a profile that specifies 
>> 48kHz audio sample rate but mythtranscode just copied the audio.  
>> I've tried setting playback to "use video as time base but that 
>> didn't help either.
>>
>> Is there anything I can do to either get Mythtv to play these shows 
>> correctly or to transcode them into something Myth will play?
>>
> I used to have some 32Khz audio on recordings when I captured analog 
> channels over firewire on my cable box.  I know I was able to convert 
> the audio on these.  You can do what you want with avidemux.  The 
> process I used was something along the following:
> - use nuvexport to export the nuv file and sql (was the very last 
> option in the menu)
> - use avidemux to fix the file
> - copy the fixed file to the myth storage directory using the same 
> file name as the original 

If you're using analog output, Myth will play them back fine once you 
properly configure your audio subsystem (and specify the appropriate 
Audio Output Device in Myth).

If you're using digital output, Myth can only play them if your hardware 
(sound card) can handle other-than-48kHz digital audio output.

Mike