Newsgroups: comp.speech
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From: ADCCHAN@1302.watstar.uwaterloo.ca
Subject: Re: speech compression
Message-ID: <ADCCHAN.20.741525690@1302.watstar.uwaterloo.ca>
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Organization: University of Waterloo
References: <1993Jun30.230950.1703@jarvis.csri.toronto.edu>
Date: Thu, 1 Jul 1993 11:21:31 GMT

In article <1993Jun30.230950.1703@jarvis.csri.toronto.edu> gao@eecg.toronto.edu (Xiangyang Gao) writes:
>From: gao@eecg.toronto.edu (Xiangyang Gao)
>Subject: speech compression
>Date: 1 Jul 93 03:09:50 GMT
>Thanks are due to those who replied my posting.
>
>Here is my original message posted on the net 
>"I am looking for a speech compression algorithm. 
>Compression does not have to be real time, but decompression
>should be done REAL TIME by a 386 or 486 PC. The speech
>quality is not terribly important, but compression rate is
>important: the higher compression rate, the better."
>
>After learning from the netters and reading articles, it seems to me
>that CELP algorithms are best. It seems to me that compressing
>to 4.8 kbits/second from 64Kbits/second is the best rate people have
>got.
>
>I am interested in knowing, if we are willing to sacrifice some
>speech quality, can we get 2.4 kbits/second? Is that possible?
>What aspects should we look at? (namely, any suggestions on how to do that?)
>The compressed speech does not have to preserve the characteristic of a 
>person's voice, as long as his speech is understandable.
>
>Thanks a lot!!
>
>Frank
>
>gao@eecg.toronto.edu

	Do you have a version of CELP?  I've a PC version but when I tried 
to compress a speech file (off a radio) and then uncompress it, the 
resulting file was unregonizable!  Sounded like a person munching on chips 
instead of voices :)  Perhaps I'm not using it correctly.  If not, then 
4800bps doesn't seem to be enough as it is.
	There is a compression 
called SPACK/SUNPACK.  It is not shareware but I believe it has extrememly 
good compression.  What is also good is that it allows you to chose the 
compression loss, which is 7-bits (lossless) to 1-bit (full lossy - produces 
a synthetic but recognizable voice).

MY QUESTION:

	Does anyone have a PC CELP that they've used on speech files and one 
that works???  Also is CELP patented, and if so by whom?

adrian

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adrian          adcchan@1302.watstar.uwaterloo.ca

