It generally keeps frames from the old video, but might repeat or drop some frames. The new video has a specified constant frame rate, and new PTSs. Make a new video from the frames and presentation time stamps (PTSs) of the input. So, for the benefit of FFmpeg users who are web-searching for answers, here is my documentation of FFmpeg’s fps video filter. I don’t know if this contribution will ultimately get accepted. I submitted it as a patch to the ffmpeg developers list.

I contributed the rewrite to the FFmpeg project. I believe the rewrite is more complete and more accurate. It is longer than the original fps filter documentation (as archived in April 2020 â€” you can check if the present documentation is any better). I took what I learned from reading that source, and did a complete rewrite of the fps filter documentation. The fps video filter source code, in file libavfilter/vf_fps.c, was an instructive read. I wanted to learn about presentation time stamps and time bases. It certainly does not answer all the questions I have, as a user trying to understand why FFmpeg is not doing what I want it to do.įortunately, FFmpeg is open source, so when the documentation fails, one can read the source. The FFmpeg media editing software is a valuable tool, but its documentation is only barely adequate.

Ffmpeg filter documentation