[mythtv-users] trandcoding messes up 6 channel audio slow audio playback

Alan Anderson andersonas at comcast.net
Thu Dec 30 16:43:33 UTC 2010


Since upgrading to mythtv 0.24 the transcoding of any show with 6 channel 
audio ends up with slow audio playback.  Playback before transcoding is fine, 
after transcoding the sound runs half speed.  Some threads here claim it is a 
Alsa issue.  But playback before transcoding is fine.  If I copy the nuv file 
over to another system and use vlc or mplayer the sound is still slow.  

I have atrpms mythtv rpm 0.24-256.fc13.x86_64 on the backend  

AMD Athlon(tm) 64 X2 Dual Core Processor 4200+  incase its some weird CPU 
related issue floating point.

I see 0.24-258 is avaialble so I'll update to that.

I see the following error in the log file.

2010-12-27 20:31:18.596 Transcoding from 
/video/recordings/3111_20101227200000.mpg to 
2010-12-27 20:31:18.887 MythCoreContext: Connecting to backend server: (try 1 of 1)
2010-12-27 20:31:18.932 Using protocol version 63
2010-12-27 20:31:18.965 MainServer::ANN Playback
2010-12-27 20:31:19.007 adding: pvr.home.lan as a client (events: 0)
2010-12-27 20:31:19.042 MainServer::ANN Monitor
2010-12-27 20:31:19.073 adding: pvr.home.lan as a client (events: 1)
2010-12-27 20:31:21.369 AFD: Opened codec 0x1ecb8f0, id(MPEG2VIDEO) 
2010-12-27 20:31:21.400 AFD: codec AC3 has 6 channels
2010-12-27 20:31:21.435 AFD: Opened codec 0x1ecc8d0, id(AC3) type(Audio)
2010-12-27 20:31:21.466 AudioOutput Error: Invalid channel count 6
2010-12-27 20:31:21.526 AudioOutput Error: Invalid channel count 6
2010-12-27 20:31:21.558 Found video height of 1088.  This is unusual and more 
than likely the video is actually 1080 so mythtranscode will treat it as such.
2010-12-27 20:31:21.594 New DB connection, total: 2

Two chanel sound is not a problemn.  Only 6 channel.

I tried to set the transcode option form mp3 to uncompressed it did not help.  

So is therea suggested adjustment for this or do I need to just turn off 

Alan Anderson

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