NHW - a free image codec

[nhw_pulsar]

Hello,

Just a very quick message to let know those who followed NHW, that the last version (v0.3.1+41) has now a good precision, in the sense that NHW image correctly resembles to the original image (for the developed -q9 to -q23 quality settings), while always keeping NHW efficient neatness.

So yes now it could be worth to adapt NHW to any image resolution. For me the best solution would be to process on the whole image dimensions, but it's really the bigger and harder to code. Another approach is the one of Martin, a great programmer and friend of mine, he has adapted NHW to 8x8, 16x16, 32x32, 64x64, 128x128, 256x256, 512x512 square sizes and he has then coded a very first (unoptimized) version of NHW that works with any image resolution by decomposing the image with these square sizes (prioritizing the largest square size first). The problem with this latter solution are the blocking artifacts (with a wavelet codec) but I have been told that deblocking filters could be quite efficient....

For now with my health, I will quietly continue to improve NHW precision, but maybe in the second half of 2026 if I am better, I will think about these solutions to adapt NHW to any image resolution, if I am alone, I think I will clearly choose Martin's solution because it is by far the fastest to deploy...

Cheers,
Raphael

[nhw_pulsar]

Hello,

Just a very quick update, as I think I'll release v0.3.2 in February, I wanted to make then a complete neatness study with objective nhw_neatness_metrics, but the new v0.3.1+42 version has (quite) worse neatness scores than v0.3.1+41, as reported by nhw_neatness_metrics, but I find that v0.3.1+42 has a better visual quality than v0.3.1+41, notably a better precision, it resembles more to the original image, so I didn't find for now a perceptual quality metrics that reflects visual quality according to my criterias and eyes...

Cheers,
Raphael

[nhw_pulsar]

Hello,

I am still thinking about Martin's (square) tiling solution for coding NHW to any image resolution, there are also some strong advantages, it is notably very more multithreading-friendly, SIMD-friendly, cache-friendly... but a very important thing is to know if we can design an efficient deblocking filter for my wavelet blocking artifacts, as I have hardly no knowledge in deblocking filters technology, it seems a very big investment and energy for me now...

Else I am ultra slowly working on NHW currently, but I hope that the next incremental improvement of v0.3.1+42 will lead to v0.3.2 version, hopefully with a real competitive precision with AOM and MPEG codecs, while still keeping NHW neatness which is a strong advantage for me...

Cheers,
Raphael

[nhw_pulsar]

Originally Posted by nhw_pulsar

Else I am ultra slowly working on NHW currently, but I hope that the next incremental improvement of v0.3.1+42 will lead to v0.3.2 version, hopefully with a real competitive precision with AOM and MPEG codecs, while still keeping NHW neatness which is a strong advantage for me...

Hello,

Just a very very quick update, I have released v0.3.1+43 version, at very first sight, I am satisfied with precision, so normally I'll see if I make other precision improvements but I think I'll transform this version into v0.3.2 later this month.

Cheers,
Raphael