View Full Version : How to change framerate of an XviD file

kitanai
24th February 2005, 01:59
As you know 23,97fps (NTSC) videos play jerky on a 25fps PAL TV. So I speed them up to 25fps by using "Reclock". Since this is the method which all TV stations use, I figured: why not change the framerate of the file instead of using an additional programm.

So how can I change to framerate of a perfectly intact 23,97fps file to play at a rate of 25fps? As far as I can tell, setting the framerate is as easy as that (VirtualDub, ...).

But how do I adjust the audio stream, so it's sync again?

Please don't call me stupid. It is just an idea since my video card does not really seem to like these speed up 23,97fps files on TV. Using Reclock, it looks good most of the time, but in between in gets somewhat jumpy. Not nice...

(if this is complete nonsense, I apologize ;) )
celtic_druid
24th February 2005, 05:30
You would need to re-encode the audio. As such this really should be in the audio forum I guess. Either way it really has nothing to do with XviD.

First you need to extract/demux the audio. This would depend on the container.

Re-encode the audio whilst changing the duration with say BeSweet.

Remux with original video with framerate changed.
*.mp4 guy
24th February 2005, 05:40
Also in case you didn't know besweet has an "change framerate from" option which may help you out here, I've never used it but I suppose this is what it's for.
kitanai
24th February 2005, 10:24
Thanks, I found all the options and it worked. However, I came to realize, that the source material must be somehow faulty. With either 23,976fps or 25fps I get a jerky motion at the exact same position - both on TV and on PC screen. Those are scenes with motion, i.e. zoom-in a pass-by-the camera, moving people and so on.

Is it possible that this behaviour was produced by encoding... ???
*.mp4 guy
24th February 2005, 10:49
Encoding more or less doesn't cause jerkyness. It sounds like the problem is interlacing or a framerate conversion of some sort and how it was processed before it was published to dvd or whatever. However to make sure check your cpu usage % during the part where the jerkyness ensues, if it's at 100% it could be your system isn't fast enough.
kitanai
24th February 2005, 10:57
No, 10% usage of my 2,8GHz cpu ;) I will go rent a DVD and see what it looks like. But that is the PAL version... ah, we'll see...