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There is definitely room for better and less gameable quality evaluation functions than PSNR and SSIM, but I would have liked to see at a minimum a description of how the algorithm was designed and a practical evaluation against other similarity metrics.

See e.g. the graphs in https://ece.uwaterloo.ca/~z70wang/research/ssimplus/ comparing human assigned scores against different similarity metrics.

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Thanks for the link. Very interesting.

I agree with you about PSNR and SSIM. There are plenty of times where they do a less than stellar job and a quick eye test makes it obvious. Unfortunately the VPxs and h.26xs of the world tune their internal comparison metrics for these to make their codecs score better on comparison tests. Consequently, this can sometimes lead to less than optimal video quality.

If this can be applied generally, work better than PSNR/SSIM and be made to run fast enough, it would be interesting to see if this could be used to improve block matching in video codecs.

*Edit grammar.

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