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Using Google's WebP Image Format with Open Tools on Linux

Mar 25, 2011, 15:02 (1 Talkback[s])
(Other stories by Nathan Willis)

"For starters, we need to understand what WebP is. The format is lossy, like standard JPEG, meaning that it uses compression to remove bytes in a way that (hopefully) the eye will not notice. JPEG files typically split the image into 8-by-8 blocks, then perform a discrete cosine transform (DCT) on each block, and toss out some of the least-significant-digit data in the resulting high frequencies. That's where most of the size savings come from; our eyes aren't as sensitive to that high-frequency data, so JPEGs sweep them under the carpet.

"There are actually quite a few options defined by the JPEG codec standard (including lossless compression), which is what gives rise to the JPEG "quality" setting — as you crank the quality down when you export an image, the algorithm adapts to toss out more and more information. But the gist remains the same."

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