To take every 15th frame, use the select filter ffmpeg -i in.mp4 -vf select=”not(mod(n\,15))”,setpts=N/FRAME_RATE/TB out.mp4 Another method is to use the framestep filter ffmpeg -i in.mp4 -vf framestep=15,setpts=N/FRAME_RATE/TB out.mp4
mp4 files cannot be simply concatenated, as the “accepted” answer suggests. If you run that, and that alone, you’ll end up with output.mp4 having only the contents of file1.mp4. That said, what you’re looking to do in the original question can in fact be done, as long as you split original file into mpeg streams … Read more
I am using Ubuntu 11.04, and I also came across this error – Unknown encoder ‘libx264’. Installing the package libavcodec-extra-53 resolved the problem. In Ubuntu 14.04 LTS the package that is needed is called libavcodec-extra-54 (and libav-tools)
If you just want to change the metadata such that mediaplayers that consider the flag play the file rotated, try something like: ffmpeg -i input.mp4 -c copy -metadata:s:v:0 rotate=90 output.mp4 as found elsewhere on stackoverflow.