Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!sdd.hp.com!decwrl!apple!vsi1!zorch!xanthian From: xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) Newsgroups: alt.sources.d Subject: Re: Compressing alt.sex.pictures files Message-ID: <1990Aug29.155925.17597@zorch.SF-Bay.ORG> Date: 29 Aug 90 15:59:25 GMT References: <1990Aug27.154419.25882@mcs.anl.gov> <1990Aug28.192024.22435@zorch.SF-Bay.ORG> <2781@network.ucsd.edu> Organization: SF Bay Public-Access Unix Lines: 47 barry@network.ucsd.edu (Barry Brown) writes: > xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes: >>winans@sirius.mcs.anl.gov (John Winans) writes in news.admin: >>>What a.s.p might be good for is a place to test image compression programs >>>and stuff like that. The acive users of the group would probably not want >>>to see it go away and might be willing to work with others to try to reduce >>>it's load on the net. >> >>Hmmm. Good idea. Here's one suggestion for an experiment. Somewhere on >>the net, a month or two back, there was a suggestion that a good way to >>compress realistic images was to XOR scan lines after the first with their >>predecessor line, then LZW compress the output. > >Problem: > >GIF files are already compressed. If you're talking about compressing GIF >files, you'll need to figure out a way to compress LZW-compressed files. Nope, only considering finding a _much_ better way to compress the original format than GIF provides. Test results conveyed to me in private email already have suggested my idea has merit. Wish I could be the one to do it and acquire the fame and glory and a compression scheme with my name on it, but at least I put up the initial suggestion. >If, on the other hand, you're talking about compressing the actual image, >then you're headed for trouble because that means defining a whole new >format. With GIFs already well supported, you (or whoever decides to pursue >this) will be in for a lot of opposition. Find a way to store the same image in 1/5th the space GIF requires, and the opposition will last about as long as a mid-summer snowfall. A little disk space is cheap, but the amount required by picture data squeezes lots of corporate and individual pocketbooks, and will motivate a lot of software retrofits of a new compression scheme. GIF -> MagicFormat and MagicFormat -> GIF converters will cover the rest of the problems, just like the overwhelming number of converters now in use. Defining a "whole new format" for image data seems to happen once a month, and defining a new compression scheme about every three months; I doubt One More Format will slow people down much. [Can you say n(n-1) converters? I knew you could! Where oh where is the one standard image storage format we so desperately need?] Kent, the man from xanth.