Preprocessing videos for editing in Final Cut Pro

It often happens that files downloaded from livestreams makes Final Cut Pro very laggy. One workaround is to use ffmpeg to re-encode the file once before editing. There will be a bit of quality hit, but the effect is minimal.

ffmpeg -i IN.mp4 -vcodec libx265 -tag:v hvc1 -crf 18 OUT.mp4

Note: hvc1 tag is required for AVKit to playback properly.