Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!mips!ptimtc!nntp-server.caltech.edu!madler From: madler@nntp-server.caltech.edu (Mark Adler) Newsgroups: comp.compression Subject: Re: JPEG compression errors ?! Message-ID: <1991Jun14.042510.12280@nntp-server.caltech.edu> Date: 14 Jun 91 04:25:10 GMT References: <1991Jun12.215238.18301@nntp-server.caltech.edu> Organization: California Institute of Technology, Pasadena Lines: 16 Jon W{tte (the left brace is actually some european character) wonders: >> So what's a "decent" compression ratio ? I'd say about 3:1 to 5:1, lossless. JPEG tacked on their rather hasty and unimaginative lossless option late in the game. I have heard that the JBIG (binary image) committee has decided to provide their own lossless compression for gray scale images, even though that is outside their charter and their name. This is in reaction to the poor performance of the JPEG lossless option, and the rumor is that the JBIG method will beat the pants off JPEG lossless. I consider this not at all unlikely. (By the way, JPEG is simply three grey scale image compressions, either lossless or lossy, usually in the YUV domain.) Mark Adler madler@tybalt.caltech.edu