Comment by kodabbb

3 years ago

Looks like there are more savings coming on lossless AVIF: https://www.reddit.com/r/AV1/comments/1b3lh08/comment/kstmbr...

4 comments

kodabbb

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JyrkiAlakuijala  3 years ago

Also more savings will come for JPEG XL soon.

Possibly mostly focused on medium and low quality.

  • kodabbb  3 years ago

    will those require a bitstream change too?

    • JyrkiAlakuijala  3 years ago

      No bitstream changes. In JPEG XL we have a 3-bit control field for each 8x8 square to guide which pixels participate in smoothing.

      The heuristics (here https://github.com/libjxl/libjxl/blob/main/lib/jxl/enc_ar_co...) for choosing that value are quite primitive and produces only two values: no smoothing and some smoothing (values 0 and 4).

      If we replace those heuristics with a search that tries out which of the values is closest to the original, we should get better quality, especially at the lowest bitrates where smoothing is important.

    • jonsneyers  3 years ago

      It is unlikely that there will be any bitstream changes in JPEG XL. There is still a lot of potential for encoder improvements within the current bitstream, both for lossy and for lossless.