Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!columbia!cunixc!cunixa.cc.columbia.edu!garton
From: garton@cunixa.cc.columbia.edu (Bradford Garton)
Newsgroups: comp.dsp
Subject: sound data compression
Message-ID: <1900@cunixc.cc.columbia.edu>
Date: 24 Sep 89 14:14:02 GMT
References: <6028@jpl-devvax.JPL.NASA.GOV> <89255.105143P85025@BARILVM.BITNET>  <7767@microsoft.UUCP> <89264.171306P85025@BARILVM.BITNET> <8909@batcomputer.tn.cornell.edu> <7814@microsoft.UUCP>
Sender: news@cunixc.cc.columbia.edu
Reply-To: brad@woof.columbia.edu (Brad Garton)
Organization: Columbia University Electronic Music Center
Lines: 13

In article <7814@microsoft.UUCP> brianw@microsoft.UUCP (Brian Willoughby) writes:
>Just by storing the *difference* between
>adjacent samples, and assuming that there are no impulses, a great
>savings in data can be achieved over storing 16 bit *absolute* values.

I've wondered about this before -- is this the technique known as
"delta modulation"?  I seem to recall some DACs made by dbx on the
market some years ago that employed such a scheme.  I gather one
of the problems was that errors would start being compounded.

Brad Garton
Columbia University Music Department
brad@woof.columbia.edu