Path: utzoo!attcan!uunet!samsung!rex!ames!pasteur!ucbvax!UMCVMB.BITNET!C503719 From: C503719@UMCVMB.BITNET ("Baird McIntosh") Newsgroups: comp.sys.amiga.tech Subject: Re: Fibonacci Compression??? Message-ID: <9004071643.AA01559@jade.berkeley.edu> Date: 7 Apr 90 16:26:22 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: University of Missouri-Columbia Lines: 32 >>original question from Sam Isaac on Apr 6, 1990 Well, first let me say that Amiga IFF sound doesn't seem to be a topic people know about-- or is it a conspiracy and they're just not talking? :-) Ok... from Perfect Sound 3.0 manual: "COMP saves the file in IFF format using Fibonacci Delta Compression, a technique that stores each sample as a four bit offset from the previous sample. This will cut your file size in half, but may reduce the sound quality considerably." For any more technical information, like what value each bit of the 4-bit offset represents, you'll need to refer to the amiga.tech gurus... I would add that the file is 1/2 size on disk, but is obviously expanded to full size when loaded into memory (for edit or play). Also, for more .fib sounds to look at, get a copy of Newtek's Demo Reel One and peruse the various directories on the first disk. Several of the samples of 'Paranoimia' are compressed using Fibonacci Delta Compression, and they still sound good. To uncompress .fib files, you can use Perfect Sound (any version); there are a few versions of the old Perfect Sound that are PD. Version 3.0, however, is *commercial*. Just load the compressed sound into the editor, and then save it using normal IFF or DUMP format. Note that the sound quality will still be the same. The file's been compressed already; saving it in a non-compressed format won't improve sound quality. The PD sound program can play compressed sounds, too. I do hope someone reading this group knows more than me about this. | Baird McIntosh | c503719@umcvmb.missouri.edu <-or-> c503719@umcvmb.bitnet | "What will we do when [the UFOs] come?" -- Hobbes "See if we can sell Mom and Dad into slavery for a Star Cruiser." -- Calvin