[Standards] Jingle audio and G.711

Peter Saint-Andre stpeter at stpeter.im
Fri Apr 11 15:42:56 UTC 2008


Olivier Crête wrote:
> 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).

Right. So making it recommended-to-implement might be best. But note
that just because it is mandatory-to-implement does not mean it is
mandatory-to-deploy or mandatory-to-use.

Peter

-- 
Peter Saint-Andre
https://stpeter.im/


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