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Old 17th May 2023, 18:57   #159  |  Link
benwaggoner
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Join Date: Jan 2006
Location: Portland, OR
Posts: 4,752
Quote:
Originally Posted by nhw_pulsar View Post
Hello,

Yes that's right that the image/video compression industry has founded its development on PSNR, SSIM, VMAF metrics improvement.And yes that's right, NHW has horrible/catastrophic PSNR, SSIM, VMAF scores, and I understand that based on these criteria, then NHW technology is not tenable.But visually, I find that if you care about neatness of image and general perception/impression you have of the image, then NHW can be visually good.

But that's right that visual impression is very subjective, for example I have tested VVC intra (VTM 12.3 slowest preset) and yes VVC has exceptional PSNR, and when you look at its results, yes VVC has an exceptional precision, but when I visually compare to NHW, I find that NHW has a better neatness, and actually all in all, with my "taste" I visually prefer the results of the latest version of NHW than VVC.(I do not test at extreme compression, as NHW is not developed for such use cases).

Would some of you share my opinion? Or definitely not? Any feedback/opinion is very welcome!
Early-stage encoders, and reference encoders in general, tend to be very tuned for metrics without much psychovisual optimization. They're also optimized for moving images more than still frames.

A more relevant comparison would be something like x264's --tune stillimage. AVIF and HEIC encoders likely have something similar, although nothing as good as a well-tuned x265.

I think I found something like this provided good web quality at a small file size:

x265 --preset placebo --range full --keyint 1 --fps 1 --crf 18 --aq-mode 4 --aq-strength 2 --psy-rd 3 --psy-rdoq 5 --rd-refine

--no-sao and a lower crf can improve detail if a bigger size isn't an issue.
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