image - JPEG library that supports variable quantization -


i have set of images (photos). want convert them using lossy image compression (preferably jpeg, i'm open other possibilities). on each image there regions of interest, use lossless or near-lossless compression.

i thought use "variable quantization" (as defined in itu-t recommendation t.84) in jpeg format set different quantization multipliers blocks intersecting regions of interest other blocks.

i've tried ijg libjpeg , mozjpeg , seems neither of these libraries support variable quantization.

do know open-source jpeg library supports variable quantization?

do know other image format supports mixing lossy , lossless compression?


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