Comment on PNG has been updated for the first time in 22 years — new spec supports HDR and animation

• The_Decryptor@aussie.zone ⁨1⁩ ⁨day⁩ ago

  JXL can do lossy images (like JPEG) and lossless ones (like PNG), and on average it’ll produce smaller file sizes than both (While beating JPEG quality wise). The killer feature is that it can do lossless recompression of existing JPEG files and shave off about 20% of the file size, and it’s reversible so you can turn those JXL files back into JPEG images for existing software.

  The downside is that it was created by Google Research (among others), but the Chrome team made AVIF instead and decided that’s what they’d support and nothing else.

  At least Safari supports it.

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  • lemmyknow@lemmy.today ⁨13⁩ ⁨hours⁩ ago

    lossless recompression of existing JPEG Uh… how does it make a JPEG lossless? Or is it lossless in that it makes a JXL out of a JPEG without affecting the original JPEG quality (i.e. no further loss beyond JPEG’s)?

    Being able to turn JPEGs into JXLs and JXLs back to JPEGs is cool, though

    What’s with the AVIF thing? Yet another I am unfamiliar with (all I know about image formats is JPG = worse quality, PNG = better quality, GIF = animated (and something WebP. Idk much about that one either))

    Also, in my research, I’ve found something about the distinction between lossless JXL vs lossy JXL. Seems like you wouldn’t be able to tell if the image is lossy or lossless just from it being a JXL

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    • The_Decryptor@aussie.zone ⁨4⁩ ⁨hours⁩ ago

      WebP is the same, it’s got a lossy mode (VP8) and a lossless mode (Which is more limited than PNG, but beats it where it overlaps). But to make it more complicated the lossless mode also has lossy processing modes, where it alters the image first to achieve smaller output sizes.

      And PNG is no different.

      People have a long habit of turning JPEG files into PNG files, the file extension won’t help you there. They also could have reduced the colour depth or resized it, all lossy operations. All it really tells you is that it can have an alpha channel.

      As for AVIF, personally I don’t like the format, it feels like an “open media” (But still patented) version of HEIF to oppose Apple. Like WebP it makes the (baseless IMO) assumption that a format designed to encode motion data is better at encoding still data than a format designed to encode still data. It’s got all the limitations of a video format (It’s got a max resolution, only supports 12bit images, and no progressive decoding), and they left out all the enhancements from WebP (The dedicated lossless mode, “lossless AVIF” files are huge and the last I checked badly supported, so nobody actually used them, and they just called very high quality settings “lossless”)

      A team inside of Google was working on WebP2 around the same time, that used AV1 but actually added the useful stuff like efficient lossless encoding, it got killed too in favour of AVIF.

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