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From: jr@bbn.com (John Robinson)
Newsgroups: comp.ivideodisc
Subject: Re: DVI exerpt
Message-ID: <34474@bbn.COM>
Date: 12 Jan 89 22:18:56 GMT
References: <494@blake.acs.washington.edu> <7070001@hpindda.HP.COM> <4470@tekgvs.GVS.TEK.COM>
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Reply-To: jr@bbn.com (John Robinson)
Organization: BBN Systems and Technologies Corporation, Cambridge MA
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In-reply-to: regisc@tekgvs.GVS.TEK.COM (Regis Crinon)

In article <4470@tekgvs.GVS.TEK.COM>, regisc@tekgvs (Regis Crinon) writes:
>In article <7070001@hpindda.HP.COM> rbean@hpindda.HP.COM (Rich Bean) writes:
>>> *ADPCM -probably Analog to Digital, Pulse Code Modulation
>>> -C. Fogg
>>
>>I think ADPCM might be:
>>  Adaptive Delta Pulse Code Modulation
>>
>
>	ADPCM stands for Adaptive Differential Pulse Code Modulation.
>	"Pulse Code Modulation" refers to the fact that the input 
>	signal has been sampled and quantized into N (generally 8 )
>	bits per samples.

ADPCM is an international (CCITT) standard for use in telephony.  The
usual digitized voice, using PCM, requires 64,000 bits/sec of
bandwidth.  ADPCM halves this to 32,000, doubling the capacity of
networks and phone switches.

I am not sure that this can apply to DVI as-is, though the general
approach might well.  The compression can be even better through the
use of a variable encoding rate rather than constant as telephone
networks require.
--
/jr
jr@bbn.com or bbn!jr