[FFmpeg-user] Problems converting image only movies

Isaksson Jörgen jogga at bitfield.se
Tue Apr 26 19:06:59 CEST 2011

Hi List,

I'm trying to overlay a QuickTime movie that consists of PNG images on top of another movie using FFMEG. I have noticed that FFMPEG doesn't seem to handle such an image only movie correctly. 

To illustrate the problem I have made a simple example movie that has one image sample for each second with a timecode written to it. When I try to convert this movie and change the framerate FFMPEG seems misinterpret samples randomly.

Download the sample movie from http://dl.dropbox.com/u/659266/timecodes.mov and try with the following simple command line:

ffmpeg -y -i timecodes.mov -r 25 timecodes_copy.mov

You will see that FFMPEG will shorten the first sample to 1 frame instead of 25? The sample that should appear on frame 26 will instead appear on frame 2?

What could be wrong? Did I find a bug?

Looking forward to a reply / Joergen

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