On Wed, 10 Jan 2007 16:23:17 +0100 Benedikt Meurer <[EMAIL PROTECTED]> babbled:
> Erlend Davidson wrote: > >> it makes use of the fact that JPEG's are DCT's > >> and you get "free" downscaling on decode by factors of 2, 4 and 8 > >> times in each > >> dimension simply by decoding the DCT at a different output res (and > >> throwing > >> out higher frequency DCT elements). it means for an incredibly faster > >> decode > >> and thus thumbnail generation is sped up massively. you speed up the > >> other half > >> of this work by using JPEG output for thumbnails. it makes a > >> difference. a > >> perceptible and measurable one. people notice. > > Could a similar optimisation be applied to PNG to generate those > > thumbnails very quickly? > > BTW. both Thunar and Nautilus use the same trick with libjpeg, so that > won't save time anyway. Saving to JPEG won't boost performance either. > What's however interesting is the saved disk space. yes it will boost performance - see my previous mail. i tested ONLY writes to png or to jpeg. jpeg won - by a huge factor compared to png. that speed test didnt do the reading bits at all. > Benedikt > > _______________________________________________ > xdg mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/xdg > -- ------------- Codito, ergo sum - "I code, therefore I am" -------------- The Rasterman (Carsten Haitzler) [EMAIL PROTECTED] 裸好多 Tokyo, Japan (東京 日本) _______________________________________________ xdg mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/xdg
