Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!ames!vsi1!zorch!amiga0!mykes From: mykes@amiga0.SF-Bay.ORG (Mike Schwartz) Newsgroups: comp.sys.amiga.audio Subject: Re: ULAW audio encoding Message-ID: Date: 31 Mar 91 07:26:16 GMT References: <1991Mar27.111945.15160@csis.dit.csiro.au> <1991Mar28.161224.8705@cbnewse.att.com> <1991Mar30.172254.26452@dialogic.com> Organization: Amiga makes it possible Lines: 47 In article <1991Mar30.172254.26452@dialogic.com> gerry@dialogic.com (Gerry Lachac) writes: >In article <1991Mar28.161224.8705@cbnewse.att.com> cwpjr@cbnewse.att.com (clyde.w.jr.phillips) writes: >>In article <1991Mar27.111945.15160@csis.dit.csiro.au>, dave@csis.dit.csiro.au (David Campbell) writes: > >>> All I want to do is convert raw 8-bit ulaw data to raw 8-bit data suitable >>> for the Amiga. Forget the IFF sound-file business. > >Get iff2ulaw. It should be avalable for ftp from >abcfd20.larc.nasa.gov, I think. It is a public domain program that >converts uLAW SparcStation sound (raw uLAW) to Amiga IFF, and raw >Amiga sound. And vice-versa. It was written for the Sun, but I >converted it to compile under Manx in about 10 minutes. Depending on >the sampling rate of your sounds, you'll have to change a define in >one of the C files. > >>is this what they call an oxymoron? 8bit data suitable for Amiga is IFF. > >Not really. Sound data doesn't *have* to be in IFF format. That's >just header information fluff with an optional compression algoritm. >All you really need is the raw sound data. > True, if you load an IFF file and play it out the DAC, all you get is a little pop sound at the beginning where the IFF header data is. >>ISDN doesn't need to use ulaw encoding for 8bit sampling >>(ie AMI & ISDN have the same standard capabilities... ) >>so what's this data from? > >I don't think you're 100% correct here. Voice data over a T-1 span >(or ISDN for that matter) comes encoded as uLAW. This is to cut back >on the amount of voice data transferred. Where can I get specs on uLAW? >-- >uunet!dialogic!gerry | "Even a dead plant turns | Dialogic Corporation > OR | over a new leaf | 300 Littleton Rd >gerry@dialogic.UUCP | when the wind blows." | Parsippany, NJ 07054 > | | (201)334-8450 -- ******************************************************** * Appendix A of the Amiga Hardware Manual tells you * * everything you need to know to take full advantage * * of the power of the Amiga. And it is only 10 pages! * ********************************************************