Re: [codec] #1: Application: 2.1. Point to point calls supporting transcoding?
"Christian Hoene" <hoene@uni-tuebingen.de> Thu, 25 March 2010 16:14 UTC
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From: Christian Hoene <hoene@uni-tuebingen.de>
To: 'James Rafferty' <James.Rafferty@dialogic.com>
References: <062.4b6a3862c443b2d8917e027f2267f4d2@tools.ietf.org> <617DF0128820F9458AC39149A627EE6C01A2947C57@MBX.dialogic.com> <000701cacad3$4b99c7c0$e2cd5740$@de> <617DF0128820F9458AC39149A627EE6C01A2947C85@MBX.dialogic.com> <000501cacb6c$37c4a0a0$a74de1e0$@de> <617DF0128820F9458AC39149A627EE6C01A2948104@MBX.dialogic.com> <001501cacbd2$d8120230$88360690$@de> <617DF0128820F9458AC39149A627EE6C01A294822A@MBX.dialogic.com> <6e9223711003241422u6b0348f5r4e249faf1724c778@mail.gmail.com> <617DF0128820F9458AC39149A627EE6C01A294826B@MBX.dialogic.com>
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Date: Thu, 25 Mar 2010 09:14:33 -0700
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Cc: codec@ietf.org
Subject: Re: [codec] #1: Application: 2.1. Point to point calls supporting transcoding?
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Hi, it might be interesting to have a look on the decision of the ITU-T regarding the requirements of the ITU-T G.718. The document TD 314 (WP 3/16) (Geneva, 22 April - 2 May 2008 ) lists in TABLE A: Performance requirements and objectives for an embedded audio coding algorithm Parameter Requirement Objective Priority 9. Interoperability for speech Interoperability with other ITU-T speech encoding standards and Interoperability with 2G and 3G mobile radio systems is desirable. Interoperability with G.722.2 @ 12,65 kb/s is of particular interest. In the second phase of characterization Annex 1: Initial List of Test Conditions for Optimization/Characterization Phase II lists the following test conditions, * NB self tandeming at R1 and at R2 * WB self tandeming at R1 and at R5 * NB Cross tandeming with G729A input * WB Cross tandeming with G722.2@12.65 input * WB Cross tandeming with G722@64kbps input To my understanding, the common consensus on this list is to have similar requirements as G.718 and to consider at least cross tandeming conditions with G722.2@12.65 in the characterization phase. With best regards, Christian --------------------------------------------------------------- Dr.-Ing. Christian Hoene Interactive Communication Systems (ICS), University of Tübingen Sand 13, 72076 Tübingen, Germany, Phone +49 7071 2970532 <http://www.net.uni-tuebingen.de/> http://www.net.uni-tuebingen.de/ From: James Rafferty [mailto:James.Rafferty@dialogic.com] Sent: Wednesday, March 24, 2010 2:46 PM To: stephen botzko Cc: Christian Hoene; codec@ietf.org Subject: RE: [codec] #1: Application: 2.1. Point to point calls supporting transcoding? Stephen, The two gateway or back-to-back gateway case will inevitably degrade quality to be G.711 level or worse. The IP IP case where there is no PSTN codec conversion is the much more interesting one for the marketplace. Id agree picking a limited set of HD codecs (for example, G.722 and G.722.2) for these tandeming purposes is the practical approach. James James Rafferty Product Line Director, Integrated Media Gateways Dialogic, Inc. 15 Crawford Street Needham, MA 02494 USA Tel: 781 433 9462 Mobile: 781 929 3895 Fax: 781 433 9268 Email: james.rafferty <mailto:james.rafferty@dialogic.com> @dialogic.com Web: www.dialogic.com This e-mail is intended only for the named recipient(s) and may contain information that is privileged, confidential and/or exempt from disclosure under applicable law. No waiver of privilege, confidence or otherwise is intended by virtue of communication via the internet. Any unauthorized use, dissemination or copying is strictly prohibited. If you have received this e-mail in error, or are not named as a recipient, please immediately notify the sender and destroy all copies of this e-mail. From: stephen botzko [mailto:stephen.botzko@gmail.com] Sent: Wednesday, March 24, 2010 2:22 PM To: James Rafferty Cc: Christian Hoene; codec@ietf.org Subject: Re: [codec] #1: Application: 2.1. Point to point calls supporting transcoding? Seems to me that there are two cases here - single gateway, and double gateway.:In the double gateway case, Endpoint A connects to Endpoint B via a gateway pair using PSTN. The audio is converted to G.711 narrowband by the first gateway, and back to the internet codec by the second. The best quality that can result is G.711, and the acoustic bandwidth is also limited to narrowband, even though both endpoints can not see the G.711 hop. Users may have other expectations, but they cannot be met. In any event, measuring the tandeming quality performance of this codec with all other standard or popular) codecs would be a very tedious exercise, and IMHO not practical. We'd have to pick one or two codecs and let it go at that. Stephen Botzko On Wed, Mar 24, 2010 at 1:59 PM, James Rafferty <James.Rafferty@dialogic.com> wrote: Hi Christian, See below (JR). James -----Original Message----- From: Christian Hoene [mailto:hoene@uni-tuebingen.de] Sent: Wednesday, March 24, 2010 9:23 PM To: James Rafferty; codec@ietf.org Subject: RE: [codec] #1: Application: 2.1. Point to point calls supporting transcoding? Hi James, >-----Original Message----- >From: James Rafferty [mailto:James.Rafferty@dialogic.com] ... >Vendors of products on these network edges will take the steps needed to get endpoints to communicate >(as driven by their service provider customers), even if it requires a codec change to complete the >call. So, the main requirement in these cases is the interoperability. Conversational quality is of lesser importance. Thus, we need not particular quality requirements beside that it works OK? JR - An ability to interop is the first consideration and quality is still important; the customer will expect (whether reasonable or not) better than PSTN quality if wideband codecs are being used by both endpoints. Christian > >James > <snip> _______________________________________________ codec mailing list codec@ietf.org https://www.ietf.org/mailman/listinfo/codec
- [codec] #1: Application: 2.1. Point to point call… codec issue tracker
- Re: [codec] #1: Application: 2.1. Point to point … James Rafferty
- Re: [codec] #1: Application: 2.1. Point to point … Christian Hoene
- Re: [codec] #1: Application: 2.1. Point to point … James Rafferty
- Re: [codec] #1: Application: 2.1. Point to point … Christian Hoene
- Re: [codec] #1: Application: 2.1. Point to point … James Rafferty
- Re: [codec] #1: Application: 2.1. Point to point … Christian Hoene
- Re: [codec] #1: Application: 2.1. Point to point … James Rafferty
- Re: [codec] #1: Application: 2.1. Point to point … stephen botzko
- Re: [codec] #1: Application: 2.1. Point to point … James Rafferty
- Re: [codec] #1: Application: 2.1. Point to point … Christian Hoene
- Re: [codec] #1: Application: 2.1. Point to point … Marc Petit-Huguenin
- Re: [codec] #1: Application: 2.1. Point to point … Michael Knappe
- Re: [codec] #1: Application: 2.1. Point to point … Marc Petit-Huguenin
- Re: [codec] #1: Application: 2.1. Point to point … stephen botzko
- Re: [codec] #1: Application: 2.1. Point to point … Marc Petit-Huguenin
- Re: [codec] #1: Application: 2.1. Point to point … Michael Knappe
- Re: [codec] #1: Application: 2.1. Point to point … Dr. Christian Hoene
- Re: [codec] #1: Application: 2.1. Point to point … codec issue tracker
- Re: [codec] #1: Application: 2.1. Point to point … stephen botzko
- Re: [codec] #1: Application: 2.1. Point to point … Christian Hoene
- Re: [codec] #1: Application: 2.1. Point to point … stephen botzko
- Re: [codec] #1: Application: 2.1. Point to point … Koen Vos
- Re: [codec] #1: Point to point calls supporting t… codec issue tracker