Somehow I thought this was going to be about detecting AV1 based on the decoded video frames, which would have been interesting!

Is launching an ffmpeg process so heavyweight that there's a reason to avoid it? If anything, it feels like it would trivialize parallelism, which is probably a feature, not a bug, if you have a bunch of videos to go through.

My first question is, where is this guy getting AV1 videos? Never seen these on the high seas.

Also, given that these videos are going to be reencoded, which is tremendously expensive, I feel that any optimization in this step is basically premature. Naively launching ffprobe 10,000 times is probably still less heavyweight than 1 reencode.