Re: [libpng:feature-requests] #32 Modern compressor
Златовратский Павел <scondo-JGs/[email protected]>
| Newsgroups | gmane.comp.graphics.png.general |
|---|---|
| Message-ID | <[email protected]> |
Well, I proposed LZMA only because it's pretty popular(among other high-level compression). My own favourite is ZPAQ. It has documentation and use some kind of virtual machine to keep description of decompression algorithm along with data. http://www.mattmahoney.net/dc/zpaq206.pdf Here some dirty test of brotli, gzip (with 7-zip) and zpaq on some picture from wikipedia: 02.01.2017 07:39 3 396 302 Marmolada,_Italy.jpg 02.01.2017 07:50 20 842 445 Marmolada_none_.png 02.01.2017 08:21 16 256 069 Marmolada_none_IDAT.brotli 02.01.2017 08:19 20 811 891 Marmolada_none_IDAT.chunk 02.01.2017 08:21 30 500 652 Marmolada_none_IDAT.rawchunk 02.01.2017 08:23 19 349 879 Marmolada_none_IDAT.rawchunk.gz 02.01.2017 08:35 19 676 279 Marmolada_none_IDAT.zpaq2 02.01.2017 08:34 12 127 402 Marmolada_none_IDAT.zpaq5 02.01.2017 07:47 15 459 765 Marmolada_paeth_.png 02.01.2017 08:04 13 766 930 Marmolada_paeth_IDAT.brotli 02.01.2017 07:48 15 459 691 Marmolada_paeth_IDAT.chunk 02.01.2017 08:04 30 500 652 Marmolada_paeth_IDAT.rawchunk 02.01.2017 08:07 15 086 510 Marmolada_paeth_IDAT.rawchunk.gz 02.01.2017 08:17 16 379 977 Marmolada_paeth_IDAT.zpaq2 02.01.2017 08:22 12 207 144 Marmolada_paeth_IDAT.zpaq5 Brotli is pretty good on default(max) settings, ZPAQ is not good when it's fast, but beat about anyone when it's slow. Also ZPAQ's own context model on max level works better without PNG filters. I think Brotli is fast way to improve compression as it's already RFC and based on deflate (so it will be easier to add for developers who doesn't rely on external libraries). ZPAQ on the other side is long way to achieve maximum compression. 02.01.2017 1:40, Chris Lilley пишет: > > LZMA is a non-starter. It was considered for WOFF 2 ( a font compression > scheme used for webfonts) and rejected because there is no adequate > documentation, just a sample implementation that everyone else must > reverse engineer. > > This is why we used Brotli compression instead. It would be a good > candidate for PNG 2.0 also. > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ png-mng-misc mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/png-mng-misc