Concat a video with itself, but in reverse, using ffmpeg

Question

I was able to reverse with:

ffmpeg -i input.mp4 -vf reverse output_reversed.mp4

And I can concat with:

ffmpeg -i input.mp4 -i input.mp4 -filter_complex "[0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output.mp4

But can I concat with a reverse version of the video, with a single command?

What I am trying to achieve is a ping pong effect, where the video plays once, then plays backwards right after.

Thanks!

Answer 1

Technically, you can do it using

ffmpeg -i input.mp4 -filter_complex "[0:v]reverse,fifo[r];[0:v][0:a][r] [0:a]concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output.mp4

But the reverse filter will use a lot of memory for large videos. I've added a fifo filter to avoid frame drops. But test and see. (I haven't reversed the audio)

If your clip has no audio, the above command will throw an error – instead, use:

ffmpeg -i input.mp4 -filter_complex "[0:v]reverse,fifo[r];[0:v][r] concat=n=2:v=1 [v]" -map "[v]" output.mp4