[MEncoder-users] mencoder does not inverse telecine properly; inccorect ofps framerate

[Lobster]

On 22/02/2011 1:07 p.m., Matt Kinni wrote:
> Hello, I have a telecined ntsc dvd that plays at 30000/1001 fps and is 6481.056 seconds long.
>
> Mencoder's -vf pullup,softskip filters work perfectly, however I'm unable to maintain an
> audio/video sync when changing the out fps to 24000/1001.
>
> For example:
>
> 24000/1001 fps * 6481.056 seconds = 155,390 frames that should be produced by mencoder.
>
> However,
> "mencoder dvd.vob -vf pullup,softskip -ofps 24000/1001 -nosound -ovc raw -of rawvideo -o
> /dev/null"
> only produces 155,332 frames, which is 2.2 seconds too short (and audio/video sync fails)!
>
> If I keep the framerate the same as the source, it produces the correct amount of frames:
>
> 30000/1001 fps * 6481.056 s = 194237 frames
> "mencoder dvd.vob -vf pullup,softskip,harddup -ofps 30000/1001 -nosound -ovc raw -of
> rawvideo -o /dev/null"
> does indeed produce exactly 194,237 frames, the same as the source, and the audio/video
> sync is ok.
>
> The point with inverse telecining is that not only do progressive frames look nicer, but
> discarding all the extra frames allows for a smaller encode.  It seams that mencoder can
> inverse telecine perfectly, it just can't change the source framerate from 29.97 to the
> desired 23.976.  Is there something I'm doing wrong?
>
> Thanks for your time

Don't use -nosound

Processing the sound with the video will allow av sync to be kept more 
easily, also use the harddup filter as the last video filter in your 
chain (if you need to duplicate frames to keep av sync it is very important)

using -of rawvideo will discard any sound output, so you don't need to 
worry about it being included in the output file, you will still need to 
specify a -oac, pcm will likely be fine.