Re: [rtcweb] Confirmation of consensus on audio codecs

Randell Jesup <randell-ietf@jesup.org> Tue, 21 August 2012 15:02 UTC

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Subject: Re: [rtcweb] Confirmation of consensus on audio codecs
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On 8/21/2012 3:57 AM, stephane.proust@orange.com wrote:
> For voice and multimedia communication services as targeted by WebRTC, two codecs, G.711 and G.722, are fully fitting the conditions to get a mandatory to implement status: a fully ensured unencumbered status, a wide implementation in devices and legacy networks and a low complexity that ensures they can be supported on any types of plate-forms and terminals.
>
> So we support both G.711 and G.722 to be specified as "mandatory to implement" codecs since G.722 will guarantee a much higher voice quality at same bit rate and almost no additional cost. At a minimum G.722 should be (strongly) recommended.

I agree G.722 should be a "SHOULD".

Note I said "I".  While in reality corporations and organizations that 
IETF contributors are associated with have opinions on IETF activities, 
officially IETF recognizes individuals as contributors.

> With respect to OPUS, it has currently no footprint on the market, its implementation complexity and resulting costs are unknown, including with respect to IPRs issues, and some performance aspects are still to be more deeply assessed, like for instance quality with packet losses and jitter which is a key issue for usage over internet.

Opus was designed within the IETF specifically to handle usage over the 
Internet better than existing codecs.

> In addition, we believe that two additional requirements are necessary to make WebRTC a future proof technology and suitable for a wide range of applications and environments:
> Firstly, the optional support of other widely deployed legacy codecs must be allowed which includes at least the codecs implemented in millions of mobile terminals: AMR and AMR-WB.

The spec does not restrict what codecs can be supported beyond the MTI 
codecs.  You can offer any codecs you support.

> Secondly, the technology must be open enough to facilitate the usage of any other codecs supported by the device but external to the browser.

This is an implementation detail for browsers and not part of the spec; 
a browser is free to offer any codecs supported by the platform if it 
wishes.

-- 
Randell Jesup
randell-ietf@jesup.org