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A comment on Faster Images using HTTP2 and Progressive JPEGs. Parent comment

Re:Faster Images using HTTP2 and Progressive JPEGs by iamaaditya on Wednesday December 28, 2016 @10:55AM (#13271260)
If it would be sufficient to have high PSNR only in the 'regions of interest', then you could use something like this [1], which uses a CNN model to predict a map, and a multiple JPEG encoding to achieve variable quality compression.

[1] https://github.com/iamaaditya/image-compression-cnn

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Re:Faster Images using HTTP2 and Progressive JPEGs by vladdanilov on Wednesday December 28, 2016 @12:56PM (#13272221)
The AI approach is interesting but there are just too many problems with it.

MozJPEG is actually using something similar called trellis quantization or soft-thresholding. The idea is to further quantize DCT coefficients in noisy areas. There are some limitations [1] though. But it's not an issue with locally sensitive metrics and can be improved with edge detection.

Another challenge here is to estimate the current image quality and the target error.

[1] https://github.com/mozilla/mozjpeg/issues/129

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