On Sunday, November 2, 2014, Stefano Sabatini <stefa...@gmail.com> wrote:
> On date Sunday 2014-11-02 13:28:05 +0100, Michael Niedermayer encoded: > > On Sun, Nov 02, 2014 at 09:09:51AM +0530, arwa arif wrote: > [...] > > > The reference code I used was " > https://github.com/carlosascari/2xBR-Filter";. > > > > I see, and i understand now where the abs bug in your code came from > > i dont think this was a good choice as reference > > Its readme even says: > > Research: Hyllian mentions a few optional implementations besides > level 2 interpolation, but i can't find any documentation on the filter > other than the byuu forum, where he only mentions them: > > Font Enhancement > > Using LVL2 Interpolation in regions plagued by shades of colors > > Using linear equation of the Straight Line to interpolate in odd > scale factors > > > > so it seems to me the reference used was not a complete implementation > > of xBR > > > > does anyone have the actual sources of the original xbr filter ? > > i did find some links but they all just redirect to some spy/add/crap > > ware download-manager > > > > also i found an example on how one of the reference pics should > > look with 2x xbr on: > > > http://forums.getpaint.net/index.php?/topic/23601-2d-image-scaling-algorithms/page-2 > > This is the link mentioned by ubitux: > http://filthypants.blogspot.it/2012/03/xbr-vs-hqx-interpolation-filter.html > > in ticket: > https://trac.ffmpeg.org/ticket/3404 > > This blog mentions Hyllian xBR algorithm: > http://board.byuu.org/viewtopic.php?f=10&t=2248 > > but the link above is dead. > > Googling for Hyllian and xBR I found this Hyallian's repository: > https://github.com/libretro/common-shaders > > The forum mentioned by Michael: > > http://forums.getpaint.net/index.php?/topic/23601-2d-image-scaling-algorithms/ > > is about a Paint.NET Plugin: > http://code.google.com/p/2dimagefilter/ > > A short description of xBR is here: > https://code.google.com/p/2dimagefilter/wiki/ImageScaling#xBR > > Since Hyllian code seems to be mentioned for the first time in > relation to byuu (a SNES emulation project), I looked for: > http://byuu.org/ > > I downloaded the higan (name of the SNES emulator) code, and grepped > for xBR but with no luck. > > So at the end I was not able to find a C reference for xBR. Probably > we should contact Hyllian himself to get advice about a (possibly > C-language) reference implementation. > Found a C++ implementation: http://sourceforge.net/p/paintown/code/HEAD/tree/trunk/src/util/graphics/sdl/xbr.cpp It says "xBR 3.3b" and I'm not sure what variant that is in the filthy pants blog. It's close to C and standalone enough, and it is licensed under the LGPL (v3 though). Found via http://wayofthepixel.net/index.php?PHPSESSID=lm3asavrs3g8u63g8k28d62u82&topic=13508.10 Timothy _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
