[mythtv-users] Losing audio on "lossless" transcode

David Boxall spamtrap at boxall.name
Fri Oct 17 01:18:13 UTC 2008


I'm a total newbie to video and Linux.  To someone with a bit of 
experience, the answer to my problem might be obvious, but it's driving 
me up the wall.

My new MythTV install records OK and the recordings play without 
problems.  Difficulties arise when I try a lossless transcode.  The 
audio disappears.  I'm recording digital terrestrial broadcasts to MPEG 
2 files.

Checking mythbackend.log, I believe this indicates the source of the 
> 2008-10-15 09:06:17.351 AFD: Opened codec 0x81f60e0, id(MPEG2VIDEO) 
> type(Video)
> 2008-10-15 09:06:17.356 AFD: codec AC3 has 0 channels
> 2008-10-15 09:06:17.362 AFD: Opened codec 0x81f6d50, id(AC3) type(Audio)
> 2008-10-15 09:06:17.496 AFD: Warning, video codec 0x81f60e0 
> id(MPEG2VIDEO) type (Video) already open.
> 2008-10-15 09:06:17.497 AFD: Warning, audio codec 0x81f6d50 id(AC3) 
> type (Audio) already open, leaving it alone.
> 2008-10-15 09:06:17.503 AFD: codec AC3 has 0 channels
> 2008-10-15 09:06:17.511 NVP: Disabling Audio, params(0,0,0)
MythTV is failing to find AC3 audio, ignoring perfectly good MP2, then 
disabling audio altogether.  Why is that?  Every transport stream I've 
examined has MP2 audio.

How can I get MythTV to do a lossless transcode on transport streams 
consisting of MPEG2 video and MP2 audio?  Neither MPEG2 nor MP2 show in 
the transcoder options.

David Boxall                    |  Any given program,
                                |  is obsolete.
                                |       --Arthur C. Clarke

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