Much lower bitrate after converting from profile 7 to 8 (workflow 8-2-1)?

[thailagraff]

When converting to profile 8.1 from 7.6, how much of a loss of bitrate is expected? I followed the 8-2-1 workflow to bake-in the FEL layer, using all default settings. The bitrate of the film went from 64 Mb/s to 27 Mb/s.

I expect a loss of bitrate due to removing the FEL layer, but a drop of over half the bitrate seems like some quality might have been lost. Is there alternative encoding settings I should be using to get near remux quality?

[R3S3t9999]

CRF encoding bitrate depends on the type of movie: grain, darkness, action, aspect ratio, lighting, etc. So sometimes the file size will be small, and other times much larger, even larger than the source but the compression quality remains consistent.

Do a screenshot comparison at frame 7-2 to see how much quality you’ve lost. The best option is to buy the Ugoos AM6B+ and watch untouched rips.

[tjayz]

I realize this is old but thought I'd add in to help others. The default in the script is CRF 15 and it is purported that CRF 17/18 is visually lossless. Even if you are using CRF 15 and hypothetically your output is visually lossless, the bitrate is going to take a big hit unless you do CRF 0 or some other setting to obtain near lossless encoding such as --lossless which I never attempted to be honest. Complete settings for x265 in link below:

https://x265.readthedocs.io/en/stable/cli.html

It makes no sense to encode in less than CRF 15 simply do what R3S3t9999 says above.

[R3S3t9999]

CRF-17 is suitable for grainy content, but for general HDR encoding, CRF-15-14 is the recommended setting.