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> The thing I'm really surprised about is that you still can't use arithmetic coding with JPEG. I was under the impression libjpeg added support in 2009 (in v7
by bawolff 1y ago
> The thing I'm really surprised about is that you still can't use arithmetic coding with JPEG.
I was under the impression libjpeg added support in 2009 (in v7). I'd assume most things support it by now.
- jchw 1y agoBelieve it or not, last I checked, many browsers and some other software (file managers, etc.) still couldn't do anything with JPEG files that have arithmetic coding. Apparently, although I haven't tried this myself, Adobe Photoshop also specifically doesn't support it.
- superjan 1y agoArithmetic coding decodes 1 bit at a time, usually in such a way that you can’t do two bits or more with SIMD instructions. So it will be slow and energy inefficient.
- adgjlsfhk1 1y agothis isn't necessarily true. zstd uses an ans which is a type of arithmetic coding which is very efficient to decode
- superjan 1y agoNice to learn about. It’s good to know the field has progressed, however the context focused on JPEG, where my point does apply.
- astrange 1y agoDeompression is limited by memory bandwidth IME, which means that more efficient compression is (almost) always more power-efficient too. (I don't have numbers for this, but it was generally agreed by the x264 team at one point.)