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A comment on The Near-Lossless Image Formats Using Ultra-Fast LZ Codecs. Parent comment

Re:The Near-Lossless Image Formats Using Ultra-Fast LZ Codecs by silvestrov on Monday April 03, 2023 @07:28AM (#35421715)
Very little, you can check by downloading the images as the LZ4 images has been reencoded into PNG so the browsers can show them.

Orig PNG: 1443667 bytes. Lossy LZ4I = 1433231, delta = -10436 bytes. A more lossy LZ4I = 1344183, delta = -99484 bytes from PNG.

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Re:The Near-Lossless Image Formats Using Ultra-Fast LZ Codecs by taylorius on Monday April 03, 2023 @08:06AM (#35422088)
Ah, good call, thank you. Of course he would use png for browsers!
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Re:The Near-Lossless Image Formats Using Ultra-Fast LZ Codecs by 1ko on Monday April 03, 2023 @08:08AM (#35422117)
That is because the png are not optimized, using lossless PNG compression (OxiPNG + AdvPNG) I get the Lossy LZ4I down to 696819 bytes.
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Re:The Near-Lossless Image Formats Using Ultra-Fast LZ Codecs by bscphil on Monday April 03, 2023 @01:16PM (#35427616)
Yes, thank you for pointing this out. To be more precise about it:

    Original PNG:    1310987 bytes
    Lossy PNG:       1154386 bytes (90.4% of LZ4i)
    Lossy LZ4i:      1276477 bytes
    More Lossy PNG:   693278 bytes
    More Lossy LZ4i:  818774 bytes (84.7% of LZ4i)
So it's notable that this lossy PNG technique has diminishing returns for LZ4i - it actually becomes more effective as a PNG preprocessor as you get more lossy, relative to LZ4i!

Still, there's a decent argument that PNG is no longer Pareto-optimal. There's stuff that gets close to the same compression ratio but decompresses much faster, and there's stuff that compresses much better and is also lossless, e.g. JPEG-XL lossless mode.

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