By: Jan Wassenberg (jan.wassenberg.delete@this.gmail.com), May 22, 2022 11:56 am
Room: Moderated Discussions
Michael S (already5chosen.delete@this.yahoo.com) on May 22, 2022 6:15 am wrote:
> I am used to formats where color (Chroma) is sampled at 1/4th to 1/16th rate of the
> intensity (Luma) and also has lower # of bits allocated per sample, which reflects
> low resolution/sensitivity of human color vision relatively to gray scale vision.
> Is JPEG XL different in that regard?
Oh, I see. Yes, we really care about high quality/fidelity and thus all datapaths are 4:4:4 (full-res chroma). It's particularly the S-cones (blue) that are lower res in human vision, so we compressed that channel more heavily, but not the other chroma channel.
> I am used to formats where color (Chroma) is sampled at 1/4th to 1/16th rate of the
> intensity (Luma) and also has lower # of bits allocated per sample, which reflects
> low resolution/sensitivity of human color vision relatively to gray scale vision.
> Is JPEG XL different in that regard?
Oh, I see. Yes, we really care about high quality/fidelity and thus all datapaths are 4:4:4 (full-res chroma). It's particularly the S-cones (blue) that are lower res in human vision, so we compressed that channel more heavily, but not the other chroma channel.