86 lines
3.2 KiB
Plaintext
86 lines
3.2 KiB
Plaintext
On December 20, I downloaded the following two emails about the patent
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status of the GSM 6.10 algorithm.
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Felix Lechner <felix.lechner@lease-up.com>
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* * *
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https://www.mail-archive.com/ietf@ietf.org/msg03978.html
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From: James P. Salsman
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Sent: Tuesday, November 14, 2000 3:03 pm
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To: [EMAIL PROTECTED]
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Cc: [EMAIL PROTECTED]
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Subject: [VPIM] GSM 6.10 is public domain; audio/wav needs registered
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Contrary to what people at VPIM meetings, lists, and on web pages
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have suggested, nobody owns any IPR on the GSM 06.10 vocodec format,
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or on any routines for encoding or decoding it. It was developed
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from published code by people who took care to publish it before it
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could be monopolized.
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Philips owns the rights to a related but different form of LPC,
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from U.S. patent 5,943,646, which was applied for more than four
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years after the publication of GSM 06.10 by ETSI. That patent is
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most likely what is confusing people about the status.
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Also, http://www.ema.org/vpimdir/specs/draft-ema-vpim-wav-00.txt
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-- the pending-in-limbo audio/wav IANA registration -- has an error:
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it reads "audio/vnd.wav"; that should be "audio/vnd.wave", which,
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by the way, hasn't been registered with IANA either. I agree with
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Keith Moore that they should be registered as identical, and I hope
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that they be registered in the same document to make that clearer.
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The definitive reference for these formats seems to be kept in
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Microsoft's Support Knowledge Base Article ID Q120253:
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http://support.microsoft.com/support/kb/articles/Q120/2/53.asp
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Cheers,
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James
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* * *
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https://www.mail-archive.com/ietf@ietf.org/msg03978.html
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Re: [VPIM] GSM 6.10 is public domain; audio/wav needs registered
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James P. Salsman Wed, 15 Nov 2000 15:56:50 -0800
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Jutta,
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Thanks for the information:
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> The patent I've seen investigated in connection with GSM 06.10
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> and Philips is the older 4,932,061 (1990)....
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Interesting. The priority date of that one is 22 March 1985.
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The practice of quantizing residual exitation in LPC vocoders was
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not novel in 1985. For an example of how people were performing
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VQ classification on the exitation residual much earlier, see:
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"Epoch extraction from linear prediction residual for
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identification of closed glottis interval", by T. Ananthapadmanabha
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and B. Yegnanarayana, in IEEE Transactions on Acoustics, Speech,
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and Signal Processing, vol. 27, no.4, pp. 309-19 (1979).
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Certainly the methods of doing such quantization described in the
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claims of patent 4,932,061 are novel, because they all explicitly
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refer to "perceptually weighting" the exitation residual. However,
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GSM 6.10 uses only four quantization vectors and a linear scaling
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factor, without any weighting based on non-linear perceptual
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modeling, so that particular set of claims do not apply to GSM 6.10.
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It also might be helpful to look at the references in the these
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GSM 6.10 descriptions published prior to ETSI's:
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"Evolution of Six Medium Bit rate Coders For The Pan-European
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Digital Mobile Radio System", by E. Natvig, in Journal On Selected
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Areas In Communications, vol. 6, no. 2, pp 324-34 (1988).
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"Speech Codec for the European Mobile Radio System", by K. Hellwig,
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P. Vary, D. Massaloux, and J.P. Petit, in Proceedings of the
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ICASSP-88, pp. 227 (April, 1988).
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Cheers,
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James
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