[Members] XSF roadmap

jehan at zemarmot.net jehan at zemarmot.net
Sat Nov 20 05:39:41 CST 2010


Hi again,

I answer myself below

On Sat, 20 Nov 2010 20:13:30 +0900, <jehan at zemarmot.net> wrote:
> On Sat, 20 Nov 2010 11:47:22 +0100, Alexander Gnauck
[...]
>> Most people use Skype because it A) just works and B) has excellent
>> voice quality. We can fix A with interop testing, but I don't know how
>> we can fix B. Is somebody on the list which has experience with free
>> codecs?
>>
> 
> Yes I was only worried about A) but B) is very true as well. 
[...]
> As for the codec, I think to remember discussions (in IETF probably?)
> were going on about having a new codec derived from the current existing
> ones because speex or others would not be that efficient for voip (or so
> I think to remember being told, I have no knowledge on the matter). What
> about this point?
> 

After a few research, I found CELT, developed by Xiph.org:
http://www.celt-codec.org/ and
https://datatracker.ietf.org/doc/draft-valin-celt-codec/

And I also found info about a Opus codec which is developed by Skype,
is apparently some container, I guess (because it says it uses SILK
which is apparently also an audio codec developed by Skype, and CELT as
well. Yes it gets complicated) and also proposed as an IETF draft. Yet
whereas CELT is completely royalty free, Opus would have some patent
issues (held by Skype of course) and may require some license fee:
https://datatracker.ietf.org/ipr/1297/
If you read the license declaration in the page, Skype really keeps a
lot of possibilities to suddenly turn on Opus users. So I hope we won't
be using such technology. I thought that any standard proposed to IETF
had to release its right to the IETF?!

Anyway is there other codecs I miss? IS CELT the state of the
art/future (for now) of voip?

Jehan


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