x265 - Always choose 10bit?

[birdie]

Originally Posted by froggy1

you're doing something wrong. I get almost half size reduction when using x265 10 bit @ CRF 21 compared to 8 bit x264 @ CRF 18. Am hard pressed to notice difference in quality between the two

post your settings, if you will

Nope, I was doing everything OK. Again, I didn't encode an uncompressed source, I re-encoded H.264 videos.

I never use any fancy encoding flags. Here's my usual encoding parameters (tune is optional):

ffmpeg -i *mkv -c:audio copy -c:v libx265 -preset veryslow -x265-params crf=18:no-sao=1:tune=grain

Again, I got negatives gains from using 10bit encoding (increased encoding time and increased file sizes with zero improvements in details retention).