I use a ffmpeg at least twice weekly for stupid side projects and non-stupid side projects; here’s a list for posterity and for my future self (who I adore) to keep track of commonly-used recipes.

Converting .webm to .mp4

ffmpeg -fflags +genpts -i ${filename}.webm -r ${target frame rate} ${target filename}.mp4

The +genpts format flag generates presentation timestamps, which IME fixes some jank when trying to copy the file over directly. The -r ${framerate} bit is not required, but it’s one more thing to sort out jank outputs.

Converting a video to frames

ffmpeg -i ${input filename} ${output filename prefix}%d.png

The %d in the output filename adds a frame number to the end. If you have like 400 frames and you want all the filename numbers padded, you can do something like %3d instead, to output something like frame_001.png instead of frame_1.png.

Converting frames back to video (or GIF)

ffmpeg -i frames/frame_%d.png output.gif

This one’s pretty obvious lol, it just ingests the frame format however you specify. There might be different rules for converting to something other than .gif but I only tested .gif for this post.

For what it’s worth, I tested both .gif with a soft G sound and .gif with a hard G sound but the output is the same.

Generating & consuming a color palette for GIFs, etc.

To generate a color palette:

ffmpeg -i input.mp4 -vf "palettegen" palette.png

To use that palette to optimize a GIF output:

ffmpeg -i frames/frame_%0d.png -i palette.png -filter_complex "paletteuse" output.gif