I can't edit the post now but you are correct. I thought the profiles were inherent to the spec, and I seem to be mixing up profiles and tunings, but it sounds

I can't edit the post now but you are correct. I thought the profiles were inherent to the spec, and I seem to be mixing up profiles and tunings, but it sounds like they're just implementation details in x264/x265 Still, it was really interesting that ffmpeg -i bluray:[filename] -c:v libx264 -crf 22 -tune film -preset slow -nr 500 produced a smaller file with higher visual quality than ffmpeg -i bluray:[filename] -c:v libx265 -crf 25 -preset slow for highly grainy inputs