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venusenvy47 • yesterday at 8:23 PM • 1 reply • view on HN

I always think of transcode and lossless as opposites. How is this achieved in this format?


Replies

ksec • yesterday at 8:34 PM

It extracts the already quantized DCT coefficients and related data from the JPEG bitstream and re-encodes them with JPEG XL’s more efficient entropy coding and container,

Think of it as zip compression that is specially designed for JPEG and putting the JPEG data in a different/better container.