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The article mentions encoding speed as something to consider, alongside compression ratio. I would argue that decoding speed is also important. A lot of the mor

The article mentions encoding speed as something to consider, alongside compression ratio. I would argue that decoding speed is also important. A lot of the more modern formats (webp, avif etc) can take significantly more CPU cycles to decode than a plain old jpg. This can slow things down noticeably,especially on mobile.

oynqr 3y ago
JPEG and JXL have the benefit of (optional) progressive decoding, so even if the image is a little larger than AVIF, you may still see content faster.
- lifthrasiir 3y ago
  Note that JPEG XL always supports progressive decoding, because the top-level format is structured in that way. The optional part is a finer-grained adjustment to make the output more suitable for specific cases.
- izacus 3y ago
  That's great, are there any comparison graphs and benchmarks showing that in real life (similarly to this article)?
  - 149765 3y ago
    A couple of videos comparing progressive decoding of jpeg, jxl and avif: https://www.youtube.com/watch?v=UphN1_7nP8U https://www.youtube.com/watch?v=UphN1_7nP8U https://www.youtube.com/watch?v=inQxEBn831w https://www.youtube.com/watch?v=inQxEBn831w There's more on the same channel, generation loss ones are really interesting.
    - izacus 3y ago
      Awesome, thanks.
  - JyrkiAlakuijala 3y ago
    https://opensource.googleblog.com/2021/09/using-saliency-in-progressive-jpeg-xl-images.html https://opensource.googleblog.com/2021/09/using-saliency-in-... can be interesting
lifthrasiir 3y ago
Any computation-intensive media format on mobile is likely using a hardware decoder module anyway, and that most frequently includes JPEG. So that comparison is not adaquate.
- kasabali 3y ago
  "computation-intensive media" = videos Seriously, when is the last time mobile phones used hardware decoding for showing images? Flip phones in 2005? I know camera apps use hardware encoding but I doubt gallery apps or browsers bother with going through the hardware decoding pipeline for hundreds of JPEG images you scroll through in seconds. And when it comes to showing a single image they'll still opt to software decoding because it's more flexible when it comes to integration, implementation, customization and format limits. So not surprisingly I'm not convinced when I repeatedly see this claim that mobile phones commonly use hardware decoding for image formats and software decoding speed doesn't matter.
  - jeroenhd 3y ago
    I don't know the current status of web browsers, ut hardware encoding and decoding for image formats is alive and well. Not really relevant for showing a 32x32 GIF arrow like on HN, but very important when browsing high resolution images with any kind of smoothness. If you don't really care about your users' battery life you can opt to disable hardware acceleration within your applications, but it's usually enabled by default, and for good reason.
    - lonjil 3y ago
      Hardware acceleration of image decoding is very uncommon in most consumer applications.
    - kasabali 3y ago
      > hardware encoding and decoding for image formats is alive and well I keep hearing and hearing this but nobody has ever yet provided a concrete real world example of smart phones using hw decoding for displaying images.

oynqr 3y ago

JPEG and JXL have the benefit of (optional) progressive decoding, so even if the image is a little larger than AVIF, you may still see content faster.

lifthrasiir 3y ago
Note that JPEG XL always supports progressive decoding, because the top-level format is structured in that way. The optional part is a finer-grained adjustment to make the output more suitable for specific cases.
izacus 3y ago
That's great, are there any comparison graphs and benchmarks showing that in real life (similarly to this article)?
- 149765 3y ago
  A couple of videos comparing progressive decoding of jpeg, jxl and avif: https://www.youtube.com/watch?v=UphN1_7nP8U https://www.youtube.com/watch?v=UphN1_7nP8U https://www.youtube.com/watch?v=inQxEBn831w https://www.youtube.com/watch?v=inQxEBn831w There's more on the same channel, generation loss ones are really interesting.
  - izacus 3y ago
    Awesome, thanks.
- JyrkiAlakuijala 3y ago
  https://opensource.googleblog.com/2021/09/using-saliency-in-progressive-jpeg-xl-images.html https://opensource.googleblog.com/2021/09/using-saliency-in-... can be interesting

lifthrasiir 3y ago

Any computation-intensive media format on mobile is likely using a hardware decoder module anyway, and that most frequently includes JPEG. So that comparison is not adaquate.

kasabali 3y ago
"computation-intensive media" = videos Seriously, when is the last time mobile phones used hardware decoding for showing images? Flip phones in 2005? I know camera apps use hardware encoding but I doubt gallery apps or browsers bother with going through the hardware decoding pipeline for hundreds of JPEG images you scroll through in seconds. And when it comes to showing a single image they'll still opt to software decoding because it's more flexible when it comes to integration, implementation, customization and format limits. So not surprisingly I'm not convinced when I repeatedly see this claim that mobile phones commonly use hardware decoding for image formats and software decoding speed doesn't matter.
- jeroenhd 3y ago
  I don't know the current status of web browsers, ut hardware encoding and decoding for image formats is alive and well. Not really relevant for showing a 32x32 GIF arrow like on HN, but very important when browsing high resolution images with any kind of smoothness. If you don't really care about your users' battery life you can opt to disable hardware acceleration within your applications, but it's usually enabled by default, and for good reason.
  - lonjil 3y ago
    Hardware acceleration of image decoding is very uncommon in most consumer applications.
  - kasabali 3y ago
    > hardware encoding and decoding for image formats is alive and well I keep hearing and hearing this but nobody has ever yet provided a concrete real world example of smart phones using hw decoding for displaying images.