Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!cis.ohio-state.edu!ucbvax!ucsd!qualcom.qualcomm.com!cancun.qualcomm.com!rdippold From: rdippold@cancun.qualcomm.com (Ron Dippold) Newsgroups: comp.compression Subject: Re: JPEG compression errors ?! Message-ID: <1991Jun4.223719.2958@qualcomm.com> Date: 4 Jun 91 22:37:19 GMT References: Sender: news@qualcomm.com Organization: Qualcomm, Inc., San Diego, CA Lines: 25 Nntp-Posting-Host: cancun.qualcomm.com In article d88-jwa@byse.nada.kth.se (Jon W{tte) writes: >.ipmce.su (Leonid A. Broukhis) writes: > > I have some problems when converting GIF files to JPEG format > (using Image Alchemy 1.4 under MS-DOS). > >Why can't people get it; conversion of GIF to JPEG is a really >stupid thing to do. JPEG works better (gives smaller output with >better output) if applied to the original 24bit RGB source than >if applied to the already-quantified 8-bit GIF images. This is >because of "unnatural" noise and high frequency generated by the >quantification process. Well, get this. GIF to JPEG works great for me on digitized GIF files of resolution 640x400x8 or better (which are the majority). With no visible loss of fidelity it compresses down to 10% to 25% of the original GIF file. It's nowhere near the savings realized on a 24-bit file, but is nothing to complain about. People get excited over 8% better compression of programs and text - being able to fit 4 to 10 times the number of GIF files on a single floppy disk in no way strikes me as a "really stupid thing to do," any more than compression of anything else. -- Standard disclaimer applies, you legalistic hacks. | Ron Dippold