Crazy family JPEG formats (2017).

[foxyshadis]

Originally Posted by hajj_3

JpegXL update: https://www.spiedigitallibrary.org/c...237.full?SSO=1

I didn't know that JPEG XL could losslessly compact JPEG images to the new format. They really are trying to be as backward compatible as possible.

[Jamaika]

New High Throughput JPEG 2000
https://htj2k.com/
Library: https://github.com/aous72/OpenJPH

The code is written in C++; the color and wavelet transform steps can employ SIMD instructions on Intel platforms. It conceivable that at some point in the future, SIMD instructions are employed to improve performance of the block (de)coder, and/or for platforms other than Intel. As it stands, on Intel Skylake i7-6700, encoding 4K 4:4:4 HDR images losslessly takes around 0.5s, and decoding takes around 0.34s; for lossy compression, performance depends on the quantisation step size (qstep), but for a high-quality image at a bitrate of around 3 bits/pixel, encoding takes around 0.27s and decoding takes 0.22s.

As it stands, the OpenJPH library needs documentation. The provided encoder ojph_compress only generates HTJ2K codestreams, with the extension j2c; the generated files lack the .jph header. Adding the .jph header is of little urgency, as the codestream contains all needed information to properly decode an image. The .jph header will be added at a future point in time. The provided decoder ojph_expand decodes .jph files, by ignoring the .jph header if it is present.

The provided command line tools ojph_compress and ojph_expand accepts and generated .pgm, .ppm, and .yuv. See the usage examples below.
https://www.sendspace.com/file/u1qesh

[foxyshadis]

OpenJPH is definitely interesting, though I'm not sure if it's promising yet. BTW, Jasper is unofficially dead: https://github.com/mdadams/jasper/issues/208