[mythtv-users] Transcoding: Audio/Video Sync

Matt Vollmar matt at vollmars.com
Tue Dec 7 17:36:43 UTC 2004

OK, I know this has been hashed around a bunch on this list, and I 
searched for anything that might help, but I couldn't find something to 
address this issue (I'm sure I didn't search long enough).  I transcoded 
(manually from the command line) a movie last night, and looked at it 
today to find an ever so slow loss of sync between audio and video.  The 
video ends up about .5 seconds faster by the end of the movie.  In the 
original, it is not thus.  Is there a way for me to fix this?  Here is 
the command line stuff I use:

mythtranscode --showprogress -p autodetect -c 1073 -s 
2004-11-25-12-00-00 -f . 2>&1 > /dev/null

ffmpeg -f rawvideo -s 480x480 -r 29.97 -i ./vidout -y -f s16le -ar 32000 
-ac 2 -i ./audout -b 1152 -vcodec mpeg1video -s 640x480 -hq -deinterlace 
-qmax 3 -qmin 13 -ar 44100 -aspect 4:3 "./You_Only_Live_Twice.mpg"

It is possible that some of my parameters are not correct.  I got these 
from someone who said they were good quality, which they are very 
acceptable.  Plus, it transcodes at just a hair slower than real-time, 
so that part rules.  Should I use fifosync on the mythtranscode command 
line or what?  Should I not deinterlace?

Thanks for any help,


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