Re: [codec] #1: Application: 2.1. Point to point calls supporting transcoding?
James Rafferty <James.Rafferty@dialogic.com> Wed, 24 March 2010 21:46 UTC
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From: James Rafferty <James.Rafferty@dialogic.com>
To: stephen botzko <stephen.botzko@gmail.com>
Date: Wed, 24 Mar 2010 17:46:24 -0400
Thread-Topic: [codec] #1: Application: 2.1. Point to point calls supporting transcoding?
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Subject: Re: [codec] #1: Application: 2.1. Point to point calls supporting transcoding?
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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. I'd 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@dialogic.com<mailto:james.rafferty@dialogic.com> Web: www.dialogic.com<http://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<mailto:James.Rafferty@dialogic.com>> wrote: Hi Christian, See below (JR). James -----Original Message----- From: Christian Hoene [mailto:hoene@uni-tuebingen.de<mailto:hoene@uni-tuebingen.de>] Sent: Wednesday, March 24, 2010 9:23 PM To: James Rafferty; codec@ietf.org<mailto: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<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<mailto: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