Comment by xeeeeeeeeeeenu | Hacker News Reader

Comment by xeeeeeeeeeeenu | Hacker News Reader

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>You know, I don't really personally care if the successor to JPEG is AVIF (based on AV1), HEIF (based on h.265, pushed by Apple), or WebP (based on V8).

You should care because those formats aren't equivalent. In many important cases, WebP performs worse than the good old JPEG[1]. It's popular mainly because of Google's brand and cargo culting. HEIF is doomed because it isn't royalty-free.

In my opinion, JPEG XL is the most interesting new format. Cloudinary published many blogposts comparing JPEG XL to the other formats, for example: [2][3]. I really recommend reading them.

BTW, Chromium has recently added support for JPEG XL decoding[4]. It's currently hidden behind a feature flag.

[1] - In medium to high BPP photographic images (which, I believe, is the most common use of lossy image compression) and in generation loss tests.

[2] - https://cloudinary.com/blog/time_for_next_gen_codecs_to_deth...

[3] - https://cloudinary.com/blog/how_jpeg_xl_compares_to_other_im...

[4] - https://chromium.googlesource.com/chromium/src/+/043d3254221...

> In medium to high BPP photographic images (which, I believe, is the most common use of lossy image compression)

I don't think this is true. Most web images shouldn't be "near lossless" they should be "not ugly", with the exception being images that are core content (think Flickr or Unsplash).

If a tech product is illustrated with a child laughing at some salad, or whatever, it doesn't matter if some detail is lost, as long as it doesn't look ugly-compressed. Users will be scrolling past it, not zooming in and comparing it to the original.

I did a performance analysis of a set of sites recently, and many have images that are 10x bigger than necessary https://jakearchibald.com/2021/f1-perf-part-2/#issue-large-p....

I mostly agree, with the caveat that a great deal of web traffic is now image sharing social sites and so any reduction in traffic size is still a good thing.

I also want to point out that people can tell the difference between when something should be good quality and when it doesn't matter. Like even on Instagram, people will forgive a pixelated meme but still be disappointed by a portrait with compression artifacts.

In my experience, folks are referring to blocky JPEG compression in those cases. Or, for digital art, specifically chroma subsampling.

I can't decide if Instagram falls under the like-Flickr use-case or not. I think on mobile, AVIF-style compression would still be best, but it could be different on desktop.

There was a paper with stats from Google Chrome, with over a billion of image sampled, saying 90%+ of image on the web has BPP over 1.0. And the median of image BPP is between 2.0 to 3.0 depending on image dimensions.

I keep swinging from one side to another, on one hand I want image size to be much smaller ( HEIF / AVIF or better yet, something based on VVC ) BPP 0.1+, on the other hand a 500x500 image is only 32KB at BPP 1.0 with JPEGXL.

Right now I am mostly alining to JPEGXL because I think AVIF or others Ultra Low BitRate format are sort of over optimising, not to mention JPEGXL decode faster and uses less resources. So it seems to be the most practical one.

> I don't think this is true. Most web images shouldn't be "near lossless" they should be "not ugly", with the exception being images that are core content (think Flickr or Unsplash).

Hard disagree here. We're talking image format, not image renderers. Whatever ends up being standardized on will eventually become the format "core content" is being stored in and transferred in. It will be the format in which my phone will save photos of my daughter, the format that her grandparents will receive those photos in (possibly twice transcoded by whatever IM they're using these days), so believe me, "not ugly" isn't gonna cut it here.

The photographers, the stock photo sites, the marketers - they'll all know how to keep images at high quality, and they have their reasons for doing so. Regular people will typically just use the defaults, so it's important to optimize the defaults for them, instead of marketing spam. If marketing spam is indeed the majority of data traffic on-line, there are other avenues to address it.

> I did a performance analysis of a set of sites recently, and many have images that are 10x bigger than necessary

Yeah, they also don't care. Why would they? Bandwidth is usually too cheap to meter for most commercial sites like these. If we try to fix their image sizes top-down by more aggressive quality reduction, some marketer will eventually notice the images "look bad", and fix it. Meanwhile, regular people will get the short end of the stick.

Phones are already using different formats for image storage. Apps are already sending those at different qualities and formats when you share them.

You shouldn't just take an image from your phone as-is, stick it on a website, and display it at 400x400 or whatever. Firstly, that won't work if you took the image with an iPhone, since it uses HEIF, which isn't supported by any browser. Secondly, it'll be orders of magnitude too big.

Sites will care about this stuff when it impacts their metrics like first-contentful-paint, which will soon begin impacting Google search ranking.

> Yeah, they also don't care. Why would they? Bandwidth is usually too cheap to meter for most commercial sites like these.

Because it's not about server bandwidth, it's about download speeds on slow connections -- mobile, bad Wi-Fi, etc.

You always want images that are no larger than they have to be for page load speeds. It's a user experience thing, not a cost thing.

I understand the theory, but the reality seems to disagree. Rarely if ever companies care about page load speeds on slow connections. Website bloat in general is a widespread problem.

Not all companies are the same.

Sure, there are tons of websites that don't optimize for page load speeds.

There are also tons that do -- including some of the largest, most popular websites on the planet, that perform very fine-tuned image compression for this purpose. Managers pore over analytics reporting 95th pctl client-side loading time, etc. So "rarely if ever" is just utterly false.

Why the defeatist attitude?

> If a tech product is illustrated with a child laughing at some salad, or whatever, it doesn't matter if some detail is lost, as long as it doesn't look ugly-compressed. Users will be scrolling past it, not zooming in and comparing it to the original.

In that case the best compression is to omit the image.

> with the exception being images that are core content

This is not the exception. This is the common case.

Instagram/Facebook posts, Tweets (a very large % have images now), TikTok/Youtube/Twitch/Netflix thumbnails, people sending photos of their family/dog/cat/houseplant to a WhatsApp/Telegram group: all of these are transferred in compressed formats.

That's even before you get into the debate of whether photojournalists' images on news articles (FAR more common than product pics on tech sites) fall under your definition of "images users scroll past", or "core content".

It seems pretty bizarre to think 10 F1 websites are representative of the common cases.

I wouldn't call those core content that needs to be maximum quality. They're normal content that needs to be non-ugly.

The examples given of core content were Flickr and Unsplash. In other words, photographic perfection.

Photographic perfection-quality on the web is definitely the exception, not the rule.

We added a preview of the JPEG-XL encoder to https://squoosh.app (and WebPv2) so you can try it with your own images.

In my experience, AVIF tends to outperform JXL in most web use-cases. However, for cases where the image should be really high quality (where the image is core content, like Flickr or Unsplash), the winner is less clear. Also, at those kinds of sizes, JPEG-XL's progressive rendering becomes an important factor.

But seriously, there's so much hype around these image formats, the best thing to do is to test it with your own images and your own eyes.

> AVIF tends to outperform JXL in most web use-cases

Matches my experience pretty well. AVIF can look quite good (for web purposes) at very low bitrates, while JXL falls apart. (JXL actually has two different modes of operation - modular mode is better at lower bitrates, but it's not considered to be JXL's main mode of operation.)

JPEG-XL seems to be designed to replace JPEG for high quality photographic images, and in my experience it's fantastic at this. I see much better results at higher bitrates (compared to AVIF), and JXL can also losslessly compress JPEGs to a smaller size.

There's a comparison between AVIF and JPEG-XL here https://afontenot.github.io/image-formats-comparison although JPEG-XL is rather fast moving target at the moment and the comparison hasn't been updated in quite a few months.

AV1 has some support for progressive images as well. It hasn't been used much in AVIF yet, though there are a couple of PRs that contain some sample images encoded progressively: https://github.com/AOMediaCodec/av1-avif/pull/134 https://github.com/AOMediaCodec/av1-avif/pull/131

As a photographer I just want a format that I can send to clients (and for my own sake) that’s better than 8 bit jpegs. Bonus points for lossless editing and re-saving. It’s ridiculous how we’ve been stuck on such an out of date format for so long when everything else in photography has gotten so advanced.

Not just their brand and cult. It's because they control search, they count page speed as a ranking factor, their benchmarks tell you to prefer webp for better performance.

> That precision suffices for images with a standard dynamic-range (SDR) and a limited color-gamut like sRGB

Is there evidence that most people perceive a difference outside of this on popular consumer hardware?

All OLED iPhones, iPad Pros, newer (2018+) Macs, and just about any "flagship" Android phone have HDR capable displays. There's tens if not hundreds of millions of devices that support HDR in the wild. Whether or not it's appreciated there's at least a huge population that can see HDR images correctly.

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