[mythtv-users] Audio lags when transcoding 720p from cable box firewire

Brian Wood beww at beww.org
Mon Mar 2 18:42:22 UTC 2009

On Monday 02 March 2009 11:18:59 Stephen Sassman wrote:
> I have been trying to transcode some 720p video captured from the
> firewire of my cable box (motorolla 6200 series). I am transcoding to
> x264 to a matroska container which works perfectly with my ivtv
> recordings. The problem that I am having is that the audio track lags
> behind the video, and it gets worse as the video progresses. By the end
> of a 90min movie, the audio can end up more than 10 sec behind the
> video. I have tried using avidemux, mencoder, and ffmpeg with the same
> result. Here is the command line that I'm using in mencoder:
> mencoder file.mpg -vf crop=944:688:168:16 -ovc x264 -x264encopts
> subq=6:me=umh:8x8dct:partitions=all:bframes=3:frameref=3:mixed_refs:dct_dec
>imate:threads=0:weight_b:crf=23 -oac copy -o file.mkv
> I use similar settings with ffmpeg and avidemux. The original mpeg has
> no issues with audio sync. I have seen mention of similar problems, but
> never a clear solution. Any idea?

Does this happen only with files which you have edited? Perhaps to remove 
commercials? I found that using ProjectX to do that solves most of these 

If it happens using raw files, or files transcoded with the lossless process, 
then you have some other problem from what I have encountered.

beww at beww.org

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