[MEncoder-users] M4V to WMV out of sync

[Bill Crockett]

Wietze <wietzuh <at> gmail.com> writes:

> Hi Everyone, When transcode a M4V video file to a WMV, the resulting
> WMV is out-of-sync. The audio gradually going out of sync with the
> video. I'm only having this problem with M4V files.
>
> I'm using the following mencoder command: "input.mp4" -of lavf
> -lavfopts format=asf -vf harddup -ovc lavc -oac lavc -lavcopts
> acodec=wmav2:vcodec=wmv2:autoaspect:keyint=25:vqscale=2  /
> :vqmin=2:aglobal=1:vglobal=1  -mc 0 -ofps 25 -o "output.wmv"
>
> While transcoding, I get the following warning several times: [wmv2 @
> 012521a0]warning, clipping 1 dct coefficients to -255..255

For dct coefficients, try increasing the "vqscale" range.  I had this 
problem and had to use vqscale=5  to stop the clipping.  However this 
was encoding from FLV to AVI.

For audio sync, try adding -demuxer lavf at the beginning.  Try it 
without -mc 0 and if no improvement try it with -noskip -mc 0.  I don't 
know why, but the -demuxer lavf had the audio and video back exactly in 
sync for videos I had problems with.

Bill