What Is JPEG XL? | Hacker News Reader

What Is JPEG XL?

jpegxl.info

40 pointsjonsneyers7 comments

JPEG XL is dead, that's what it is after latest Chromium statement. I wished we could just finally move from JPEG to something more efficient, I don't even care what it is because pretty much ANYTHING is better, I would be fine even with old WebP if it was widely supported by phone cameras and apps natively and in consumer electronics, but still 10 years later most of the apps keep taking photos to JPEG. Well at least with video there is progress and no recent device has problem to work with X265 whether it's my mobile or TV.

Most cameras produce 4:4:4 JPEGs at a high quality (something around q96 or more, on the libjpeg scale). WebP cannot do that kind of quality: it uses forced 4:2:0 and not full-range 8-bit YCbCr like JPEG but tv-range 8-bit, which effectively has the effect of reducing the bit depth / color accuracy. In RGB terms, this boils down to more or less 6.5 bits for R and B and 7 bits for G, and having only a 1:2 downsampled image for the reds and blues. For web delivery of SDR images that is (just barely, and not in all cases) acceptable, but for prosumer/professional photography this is not at all sufficient.

What is needed to get a big improvement for photography is a format that can do high-quality high-bitdepth, which would eliminate most of the need for shooting in RAW formats. If the format is precise enough to accurately represent the dynamic range of the actual data (which typically around 14 bits per sample), then this would be 'good enough' to no longer need bulky RAW files. Currently JPEG XL is the only format that can do that — JPEG and WebP cannot do it, and even HEIC and AVIF cannot really do that (especially not their hardware implementations).

It will take a while before cameras will start deploying JPEG XL, but at least now Adobe Camera Raw, Affinity Photo, and darktable support JPEG XL, photographers can already start converting their RAWs to JPEG XL and save tons of storage. Of course it would be even better if cameras can directly produce JPEG XL, and I think this will be a killer feature for the first cameras that will do that — effectively it will increase on-camera storage capacity by an order of magnitude and tremendously improve interoperability.

Chrome's decision is of course regrettable but I hope they will eventually revisit it as adoption of JPEG XL increases.

98% population don't care about all those acronyms you used. If I can have 5-10 times smaller WebP file at comparable quality than JPEG I don't really care about details, only thing I care about it's support in all devices I use. If I was going after superior quality I would be shooting in RAW and not JPG anyway.

Well but you cannot have a 5-10 times smaller WebP at a quality comparable to JPEG. If low quality is good enough for you, then you can get maybe a 10-20% saving compared to JPEG (not 80-90% as you are claiming, that is ridiculous). At higher quality, WebP does not really save anything compared to JPEG. At camera quality: WebP cannot even do that, its lossy mode has a maximum quality that is well below the kind of visually lossless encoding cameras use.

Even Google themselves claimed you get only a 30% reduction in file size when using WebP, and that's been show many times to be exaggerated — it's more like 15%. WebP has been advertised by Google for a decade, but the format is a dead-end.

WebP is based on the VP8 codec, which has lost in the market to even older codecs, later has been obsoleted by VP9, and the tech has later been upgraded to VP10 and AV1. WebP is already a few generations behind the state of the art, and it wasn't even good when it was new.

People sometimes see huge difference in file size when converting JPEG to WebP, but that's 10%-15% reduction from improved compression, and the rest of reduction is from loss of quality caused by WebP's limitations and lossy nature of the conversion.

WebP is like a magic backpack that makes your baggage 5-10 lighter — by having a hole and dropping your items.

What is this annoying unusuable scroll behavior? And arrow keys / pguppgdown don't work at all.

It's scroll-snapping, but it looks like it does more harm than good on some browsers so I just removed it. Please refresh :)

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