[Standards] Jingle audio and G.711

Olivier Crête olivier.crete at collabora.co.uk
Fri Apr 11 14:45:47 UTC 2008


On Fri, 2008-04-11 at 08:37 -0600, Peter Saint-Andre wrote:
> Olivier Crête wrote:
> > On Fri, 2008-04-11 at 06:50 -0600, Peter Saint-Andre wrote:
> >> Paul Witty wrote:
> >>> Peter Saint-Andre wrote:
> >>>> Lauri Kaila wrote:
> >>>>  
> >>>>> 2008/4/10, Peter Saint-Andre <stpeter at stpeter.im>:
> >>>>>    
> >>>>>> Offlist, someone mentioned to me that it might be appropriate for
> >>>>>>  XEP-0167 to recommend or even require support for the ITU-T's G.711
> >>>>>>  technology, which is represented by payload-types 0 (PCMU) and 8
> >>>>>> (PCMA)
> >>>>>>  as registered with the IANA.
> >>>>>>  http://www.itu.int/rec/T-REC-G.711/e
> >>>>>>
> >>>>>>  Thoughts?
> >>>>>>
> >>>>>>       
> >>>>> I think 64 kbits/s is too much to be mandatory.
> >>>>>     
> >>>> I think the idea was that G.711 is supported everywhere, so recommending
> >>>> support for it in Jingle would help interoperability with existing SIP
> >>>> networks and the PSTN.
> >>>>   
> >>> Indeed.  We have a Jingle->SIP/H.323 gateway.  I don't know of any SIP
> >>> or H.323 endpoints which support Speex, so if that is the only
> >>> recommended codec for Jingle audio, then we have to be prepared to
> >>> transcode the audio in all cases.  By guaranteeing a minimum of G.711,
> >>> we should be always able to gateway between protocols without
> >>> transcoding if so desired, even if we may need to transcode for higher
> >>> quality audio e.g. Speex to AAC.
> >> Right, that's the idea.
> >>
> >> Is basic G.711 still patent-encumbered in any way? I'll have to do some
> >> research on that...
> > 
> > The G.711 standard was published in 1972, I don't know of any
> > jurisdiction where patents can last that long.
> 
> I don't either. :) A quick search didn't yield any patents outstanding,
> so I think it's probably safe (IANAL etc.). Now the question is whether
> it should be mandatory to implement or just recomended.

Making it mandatory will be a problem in any low-bandwidth environment
(its still 64kpbs.., compared to 6.4kbps for G.729).

-- 
Olivier Crête
olivier.crete at collabora.co.uk
Collabora Ltd
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