[FFmpeg-devel] New Filter (dejudder)

Nicholas Robbins nickrobbins at yahoo.com
Thu Jan 23 17:30:58 CET 2014


I was looking for a filter to remove judder in a variable frame rate file. For instance, if there are frames with PTS's

... 08 16 24 40 48 56 64 80 88 ... (as might result from -vf pullup)

it should then pace them out to 

... 07 17 27 37 47 57 67 77 87 ...

I've looked around I don't think such a filter currently exists. 

If the whole file was one frame rate, then -vf fps or -r would do what I want, but the original file is mixed 30fps and 24fps telescened to 30fps. It seems that fps=120 should work, but it producess ....AAAABBBBCCCCDDDDDDDDEEEE.... from ...ABCD_EFG... just oversampling the judder.

I've got an algorithm that does what I want as far as working with the PTS's. I've coded it up in a simple C program, and I think I've gotten it put into a filter.

However, I've never contributed to a project of the complexity of ffmpeg before. I've looked at http://wiki.multimedia.cx/index.php?title=FFmpeg_filter_howto and I've looked around the filters in git ffmpeg/libavfilter and I think I'm on the right track, but I imagine I've missed something or misunderstood something. Is this a good place to post what I have so far? If not any suggestions for where I should go?

-Nicholas Robbins

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