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faster lossless WebP encoding - #65
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- Hash chain candidates are skipped without measuring the match when they can't win: the chain runs from near to far, so a candidate no closer than the best one only wins by being longer, which it can't be if it differs right after the best length (zlib's check). - The left and above references are checked directly instead of through an array created for every pixel. - The per-channel helpers of the predictors (select, the clamped ones) and the residual cost are unrolled. The files are byte-identical: lossless encoding checked against master on 1593 images. Encoding a 1920×1080 photo is about 15% faster. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01YJgRK5qpwJEbHPuFv6kgAQ
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Faster lossless WebP encoding:
Identical results: files are byte-identical, checked against master on 1593 images (2828 results, 0 different).
Speed: encoding a 1920×1080 photo takes 9–15% less time. The changelog says about 15%.