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    A new PNG spec

    (www.programmax.net)
    618 points bluedel | 11 comments | 24 Jun 25 13:01 UTC | HN request time: 0.001s | source | bottom
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    albert_e ◴[25 Jun 25 05:09 UTC] No.44373786[source]▶
    So animated GIFs can be replaced by Animated PNGs with alpha blending with transparent backgrounds and lossless compression! Some nostalgia from 2000s websites can be revived and relived :)

    Curious if Animated SVGs are also a thing. I remember seeing some Javascript based SVG animations (it was a animated chatbot avatar) - but not sure if there is any standard framework.

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    riffraff ◴[25 Jun 25 05:22 UTC] No.44373868[source]▶
    I was under the impression many gifs these days are actually served as soundless videos, as those basically compress better.

    Can animated PNG beat av1 or whatever?

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    1. armada651 ◴[25 Jun 25 07:30 UTC] No.44374550[source]▶
    > Can animated PNG beat av1 or whatever?

    Animated PNGs can't beat GIF nevermind video compression algorithms.

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    2. jeroenhd ◴[25 Jun 25 08:13 UTC] No.44374811[source]▶
    Once you add more than 256 different colours in total, GIF explodes in terms of file size. It's great for small, compact images with limited colour information, but it can't compete with APNG when the image becomes more detailed than what you'd find on Geocities.
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    3. Aissen ◴[25 Jun 25 08:34 UTC] No.44374952[source]▶
    > Animated PNGs can't beat GIF nevermind video compression algorithms.

    Not entirely true, it depends on what's being displayed, see a few simple tests specifically constructed to show how much better APNG can be vs GIF and {,lossy} webp: http://littlesvr.ca/apng/gif_apng_webp.html

    Of course I don't think it generalizes all that well…

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    4. ◴[25 Jun 25 10:18 UTC] No.44375573[source]▶
    5. bmacho ◴[25 Jun 25 10:28 UTC] No.44375646[source]▶
    I tried these examples on ezgif, and indeed apng manages to be smaller than webp every single time. Weird, I was under the impression that webp was almost always smaller? Is this because GIF images are already special, or apng uses better compression than png?

    edit: using the same ezgif webp and apng on a H.264 source, apng is suddenly 10x the size than webp. It seems apng is only better if the source is gif

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    6. Aissen ◴[25 Jun 25 11:37 UTC] No.44376096{3}[source]▶
    I have no idea! I actually hoped someone would show a much more comprehensive and serious benchmark in response, but that has failed to materialize.
    7. pornel ◴[25 Jun 25 15:24 UTC] No.44378383[source]▶
    No, APNG explodes in size in that case.

    In APNG it's either the same 256 colors for the whole animation, or you have to use 24-bit color. That makes the pixel data 3 times larger, which makes zlib's compression window effectively 3 times smaller, hurting compression.

    OTOH GIF can add 256 new colors with each frame, so it can exceed 256 colors without the cost of switching all the way to 16.7 million colors.

    8. armada651 ◴[25 Jun 25 18:21 UTC] No.44380354[source]▶
    You're correct and I was considering adding a footnote that if you use indexed colors like a GIF then PNG can beat GIF due to better compression algorithms. But when most people think of APNG they think of lossless compression rather than lossy compression.
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    9. fc417fc802 ◴[26 Jun 25 03:34 UTC] No.44383964{3}[source]▶
    I would guess that apng only wins when indexed colors can be used. That guess would match what you saw using an h264 file for the source.
    10. account42 ◴[26 Jun 25 09:32 UTC] No.44385678{3}[source]▶
    Indexed can be lossless when the source already uses few colors, e.g. because you want to improve the compression of an existing GIF or limit colors for stylistic choice (common in pixel art).
    11. account42 ◴[26 Jun 25 09:34 UTC] No.44385690{3}[source]▶
    Almost like video codecs and animated images are different niches that optimize for different content.