Newsgroups: comp.speech
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From: lupini@cs.sfu.ca (Peter Lupini)
Subject: Re: Embedded ADPCM CCITT standard
Message-ID: <1994Sep24.051416.8613@cs.sfu.ca>
Organization: Faculty of Applied Science, Simon Fraser University
References: <1994Sep22.180354.2659@cs.sfu.ca> <35ura3$sog@genesis.cmr.com>
Date: Sat, 24 Sep 1994 05:14:16 GMT
Lines: 19

>In article <1994Sep22.180354.2659@cs.sfu.ca>, <lupini@cs.sfu.ca> writes:
>> I have heard that the standard
>> is G.722, but I can't find any information to confirm this.
>> The FAQ mentions G.722, but it is an error - it should read G.721.
>
In article <35ura3$sog@genesis.cmr.com>,  <jsnyder@genesis.cmr.com> wrote:
>
>G.721 is described as "32 kbit/ADPCM", and 7.722 as "7 kHz Audio-Coding
>within 64 kbit/s" (Sub-Band ADPCM) in the CCITT Blue Book Vol III. I've
>seen more reference to the G.721 in books and articles.

Thanks - I had the wrong number. It seems that that the standard I 
was looking for is G.727 - Embedded ADPCM. That is, lower rates 
can be obtained from the full rate ADPCM bit stream by simply 
deleting bits and using zero fill bits instead. 

Peter


