Add hellishly slow level 13 compression#452
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Add the devil's compression level: an extremely slow, ratio first mode above level 12 that spends much more CPU time to squeeze DEFLATE output a little further. On the Silesia corpus, level 13 reduces total output by 86'990 bytes or 0.134% compared with level 12, while total runtime grows from 29.1 seconds to 1'670.5 seconds, making it about 57 times slower. Level 13 extends the near optimal parser with costlier parameters, larger text like blocks, broader parse scoring, delayed split commitment, and saved measured parses for final flushing. Expose the new level through the public API, command line tools, and compression level scripts.
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Full benchamrk on the Silesia corpus:
and here a bit more explanation how it works: https://kirill.korins.ky/articles/hellishly-slow-level-13-deflate-compression/ |
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@catap - Interesting! It seems tuned for textual information... does it benefit png images? How do your results compare to zopfli? I'm surprised at the cost of your approach, for <0.3% gain. |
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@ace-dent base on table in turtledeflate, it loses :) |
Author
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but it can't have infinity loop like Efficient-Compression-Tool and turtledeflate |
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Add the devil's compression level: an extremely slow, ratio first mode above level 12 that spends much more CPU time to squeeze DEFLATE output a little further.
On the Silesia corpus, level 13 reduces total output by 86'990 bytes or 0.134% compared with level 12, while total runtime grows from 29.1 seconds to 1'670.5 seconds, making it about 57 times slower.
Level 13 extends the near optimal parser with costlier parameters, larger text like blocks, broader parse scoring, delayed split commitment, and saved measured parses for final flushing.
Expose the new level through the public API, command line tools, and compression level scripts.