they look pretty much like a show-stopper to me (personal opinion), esp. since JPEG of same size (30k) doesn't have them:
Originally Posted by Raphael Canut
Thank you for your professional opinion.So I will reconsider discoloration and aliasing artifacts, because for now I preferred spending those bits elsewhere in the bitstream where result would be visually more pleasant despite these artifacts... I will try to do it when I would have finished extreme compression because I think at extreme compression these artifacts are more tolerated...
Depsite the fact that the NHW Project performs really poorly on this image, I visually still prefer it compared to the JPEG image you've linked because it has more neatness...
Neatness is the main advantage of the NHW Project I would like to maintain along with a very fast encoding/decoding speed, so I'll also have to see if correcting these artifacts is compatible with these goals...
Many thanks again!
Just a quick message to let you know, as I had some remarks, that the NHW Project is not better than HEVC at very high and extreme compression on all images.
After first tests, the NHW Project is competitive with HEVC at extreme compression on rather good quality images, that is to say images that were not "quite degraded" by JPEG compression and artifacts...
For now, I had the opinion of Skal with the discoloration and aliasing artifacts that I must take into account, but any other opinion would be also very welcome!
For those interested, I have added a new -l19 "extreme" compression quality setting to the NHW Project.This -l19 quality setting is really competitive with x265 (HEVC) on rather good quality images.
An important remark: we can really save 2.5KB in average per .nhw compressed file as the entropy coding schemes are not optimal, especially at extreme compression.I have the fast ideas to improve it.Will have to do it.
More at: http://nhwcodec.blogspot.com/
I will have to study a little deeper the psychovisual model I use for extreme compression, because on 5% of the images, certain kinds of images, it is better to switch it off...
Again, it would be great if you could consider the NHW Project as furthermore it is royalty-free and ultra-fast, I know it is impossible to compete with VP9,HEVC, AOM AV1, VVC, but maybe there would be a niche these codecs don't cover and where the NHW Project could shine, because I feel it still lacks of consideration by the industry (but of course this is only my opinion)...