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From a purely theoretical viewpoint 10+ bits encoding will lead into slightly better results even if rendered using a traditional 8 bit decoder. One source of e
by JyrkiAlakuijala 3y ago
From a purely theoretical viewpoint 10+ bits encoding will lead into slightly better results even if rendered using a traditional 8 bit decoder. One source of error has been removed from the pipeline.
- vlovich123 3y agoHow does the data get encoded into 10.5 bits but displayable correctly by an 8 bit decoder while also potentially displaying even more accurately by a 10 bit decoder?
- JyrkiAlakuijala 3y agoThrough non-standard API extensions you can provide a 16 bit data buffer to jpegli. The data is carefully encoded in the dct-coefficients. They are 12 bits so in some situations you can get even 12 bit precision. Quantization errors however sum up and worst case is about 7 bits. Luckily it occurs only in the most noisy environments and in smooth slopes we can get 10.5 bits or so.
- lonjil 3y ago8-bit JPEG actually uses 12-bit DCT coefficients, and traditional JPEG coders have lots of errors due to rounding to 8 bits quite often, while Jpegli always uses floating point internally.
- Sesse__ 3y agoIdeally, the decoder should be dithering, I suppose. (I know of zero JPEG decoders that do this in practice.)
- lonjil 3y agoJpegli, of course, does this when you ask for 8 bit output.
- qingcharles 3y agoHas there been any outreach to get a new HDR decoder for the extra bits into any software? I might be wrong, but it seems like Apple is the primary game in town for supporting HDR. How do you intend to persuade Apple to upgrade their JPG decoder to support Jpegli? p.s. keep up the great work!
- JyrkiAlakuijala 3y agoI tried to reach to their devrel person Jen Simmons here: https://twitter.com/jyzg/status/1763141558042243470 https://twitter.com/jyzg/status/1763141558042243470 I didn't follow up and I don't know if she read it or understood the proposal.