2020.04.18 12:15 "[Tiff] Updating zlib library", by Vincent Ripoll

2020.04.18 12:51 "Re: [Tiff] Updating zlib library", by Even Rouault

Vincent,

interesting. From my own perspective, I'd be more interested in *faster* alternatives to zlib than slightly better compression rates. Looking quickly at the links you provide, libdeflate advertize greater speeds, but I'd be interested in seing benchmarks.

For applications that use TIFF in several stages of complex processing, I now see ZSTD being used for intermediate steps due to its uncomparable speed * compression_ratio, and DEFLATE/LZW being used for the final user-facing product to maximize compatibility as ZSTD-compressed TIFF are presumably non-standard, outside of libtiff ecosystem.

One potential issue with libdeflate mentionned in its toplevel readme is that it doesn't support streaming operations, and that's needed by libtiff for some TIFF formulations, like single-strip files where users read or write by scanline. But for reasonably small strips or tiles, where the TIFFReadEncoded() interface is used, libdeflate could potentially be used (But that depends a bit of the speed increase it provides over zlib). So a fully compliant libtiff build would still have to use zlib for the odd cases.

zopfli seems to advertize only better compression rate, but slower compression times.

Even

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