Re: [Libjpeg-turbo-devel] Further research regarding the effectiveness of SmartScale
SIMD-accelerated libjpeg-compatible JPEG codec library
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From: DRC <dco...@us...> - 2013-01-17 04:10:08
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On 1/16/13 9:05 AM, Siarhei Siamashka wrote: > Thanks a lot for the clarification about the status of JPEG 9 > regarding its conformance with the industrial standards. I tried to > search a bit and found at least one open source project, which > implements the real standard JPEG LS part-2 (ITU T.870/ISO-14495-2): > https://github.com/thorfdbg/libjpeg > > Lossless encoding can be done with: > ./jpeg -c -ls 0 -cls inputfile.ppm outputfile.jpg > > Lossless decoding of these files back to PPM can be done with: > ./jpeg -c -cls inputfile.jpg outputfile.ppm > > Comparing it for encoding http://www.r0k.us/graphics/kodak/kodak/ images > with the rest of the lossless codecs mentioned earlier: > > Total size for JPEG 9 : 12941527 (~12.3 MiB) > Total size for WebP 0.2.1 : 11358510 (~10.8 MiB) > Total size for patched WebP 0.2.1 : 11245066 (~10.7 MiB) > Total size for thorfdbg JPEG-LS : 11195469 (~10.7 MiB) Yeah, this is why I released the report on a wiki. :) I've added results for JPEG-LS to my analysis: http://www.libjpeg-turbo.org/About/SmartScale-Lossless I did find one case in which jpeg-9 produced a 12% better compression ratio (but took twice as long to do it) and one case in which it compressed 18% faster (but also 18% worse.) In general, I find no compelling reason to use lossless SmartScale over JPEG-LS. |