
I doubt there will be many people currently trying to encode 10-bit raw uncompressed analogue video captures to FFV1 but it appears that 2-pass mode is completely broken for anything that's more than 8-bit and I've just wasted like 2 days trying to figure out why before finally finding that it's a bug reported 5 years ago that still isn't fixed: https://trac.ffmpeg.org/ticket/5405