Comskip out of sync when recording is transcoded

[pme]

I have a strange problem.

When transcoding my recordings to a .mp4 file (using the following tags for video and audio: -vtag xvid -vcodec mpeg4 -deinterlace -acodec aac targetExtension=".mp4") my comskip gets out of sync.

If I on the other hand transcode to an .avi file (using the following tags for video and audio: -f avi -vcodec xvid -vtag XVID -deinterlace -acodec mp3 targetExtension=".avi") the comskip timing is correct.

The bitrate and quality is the same for both transcodings, and therefor leftout.

I don't know which codec is used for each format.

Any suggestions on what's wrong, or how to how to get it right?

/P-M

[sub]

Sorry, I dont know. I've never tried transcoding to a .mp4 file.

[pme]

Here's some delayed feedback (the workload on work is huge right now).

I have troubles getting my AVI files to work in VLC on my mac (using either a SMB share or the web interface). It complains on a non working index.
If I use mp4 the problem is gone.

Right now my windows machine is to weak to cope with anything else than recording and comskip. I'll upgrade in the near future and will probably be able to use both Videoredo and the more fancy scripts to use mencoder instead of ffmpeg. Until then .mp4 would have been a simple workaround.

thanks anyway

[erik]

How much is "out of sync"?

[sub]

What frame rate is the mp4 file? Is it 25fps or something else?

[pme]

Erik: The amount of "out of sync" is proportional to the time played. A commercial break in the beginning is just 5-10 seconds of, but after 50 minutes it's almost the whole break (5-6 min).

sub: I've tried to both leave the fps out in the ffmpeg settings, and forcing it to the same as the mpg file (25 fps) with the same result.

Right now we're in the pipeline of buing a new htpc (the current one is an old Scaleo C with a 3 GHz Celeron D, which takes forever to encode avi/mp4). When we've finally upgraded the hardware I'll try again. Until then I'll just have to watch the movies over smb (and recreate the avi index) instead.

thanks

/P-M