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I agree with all of your comments. Some remarks though: (Disclaimer: I'm the author of FLIF) - interpolation is not the only difference between PNG and FLIF in

I agree with all of your comments. Some remarks though: (Disclaimer: I'm the author of FLIF) - interpolation is not the only difference between PNG and FLIF in terms of progressive decoding. Another difference is that instead of doing the interlacing on RGB pixels, it does it on YCoCg pixels with priority given to Y, so intermediate steps are effectively chroma subsampled (or in other words you get luma faster at higher resolutions). - lossless is indeed (currently?) too costly for photographic material on the web, because we can indeed afford some loss and still look good. However, you can still have a lossy encoder that uses a lossless format as a target: e.g. instead of encoding the deltas at full precision, you could throw away some least significant mantissa bits (those behave the most like incompressible noise) and still get visually good results. - In future work: Progressive JPEG with the Huffman encoding replaced by FLIF's MANIAC entropy coding should be an interesting direction...

pornel 11y ago
Thanks! Sorry to rain on your parade :) > In future work: Progressive JPEG with the Huffman encoding replaced by FLIF's MANIAC entropy coding should be an interesting direction... That would be super cool.
gfody 11y ago
> However, you can still have a lossy encoder that uses a lossless format as a target I wish "lossy-ness" was always an encoder parameter and never an intrinsic property of the container. The world would be a better place if we made this distinction early on. Instead every time a jpeg is edited and resaved the world gets a little more potatoey.
- krick 11y ago
  Maybe I am mistaken, but there's no real solution here: either you open a lossy image, edit it and save as lossless (which you easily can do), gaining in size but keeping the quality as is at this point, or (if you want to get smaller image still even after editing lossy image) you must re-encode it as lossy and make image a little more potatoey. However, as silly as it might seem, I find having a clear distinction between media formats and unique file extension for each a huge usability improvement. A must, basically. I absolutely hate currently existing convention of distributing animated pictures as a webm or mp4 video container w/o audio track. It might seem insignificant: after all, that's what they are — audio-less video files. But because of that I can no longer mv *.gif pictures/animated/. What's even worse, I cannot make my file manager open these "moving pictures" with some other program, because there's no way it could know that it's just looped animation, and not a "real movie". For the same reason I dislike (even though not that much) formats that can be (and are widely used as) both lossy and loseless while having the same container and file extension.
  - gfody 11y ago
    No, when the format is implicitly lossless then editing and saving is lossless. Discarding more information to make the file compress better is done separately, with a different tool even.
  - girvo 11y ago
    That's one of the reasons why I like the fact that some websites treat them as "gifv" files, even though they are just mp4.

pornel 11y ago

Thanks! Sorry to rain on your parade :) > In future work: Progressive JPEG with the Huffman encoding replaced by FLIF's MANIAC entropy coding should be an interesting direction... That would be super cool.

gfody 11y ago

> However, you can still have a lossy encoder that uses a lossless format as a target I wish "lossy-ness" was always an encoder parameter and never an intrinsic property of the container. The world would be a better place if we made this distinction early on. Instead every time a jpeg is edited and resaved the world gets a little more potatoey.

krick 11y ago
Maybe I am mistaken, but there's no real solution here: either you open a lossy image, edit it and save as lossless (which you easily can do), gaining in size but keeping the quality as is at this point, or (if you want to get smaller image still even after editing lossy image) you must re-encode it as lossy and make image a little more potatoey. However, as silly as it might seem, I find having a clear distinction between media formats and unique file extension for each a huge usability improvement. A must, basically. I absolutely hate currently existing convention of distributing animated pictures as a webm or mp4 video container w/o audio track. It might seem insignificant: after all, that's what they are — audio-less video files. But because of that I can no longer mv *.gif pictures/animated/. What's even worse, I cannot make my file manager open these "moving pictures" with some other program, because there's no way it could know that it's just looped animation, and not a "real movie". For the same reason I dislike (even though not that much) formats that can be (and are widely used as) both lossy and loseless while having the same container and file extension.
- gfody 11y ago
  No, when the format is implicitly lossless then editing and saving is lossless. Discarding more information to make the file compress better is done separately, with a different tool even.
- girvo 11y ago
  That's one of the reasons why I like the fact that some websites treat them as "gifv" files, even though they are just mp4.