[asterisk-dev] iLBC codec

[Artem Makhutov]

Hello,

Steve Underwood schrieb:
[...]
>> The main benefit of iLBC codce is that is has a _MUCH_ better audio
>> quality then g729 and still requires pretty low bandwith and you do
>> not have to pay license fees for using ilbc...

> iLBC actually sounds a little worse than G.729, despite running at twice
> the bit rate. What you have probably experienced is the effect of
> chaining a cell phone codec with G.729 and iLBC. Any chaining of
> multiple low bit rate codecs produces horrible results, but G.729 + cell
> phone is far worse than G.729 + iLBC. This can make it an interesting
> option.

We had tested G729 vs iLBC vs G711 directly with Cisco 69xx phones on a 
Cisco Callmanager installation. We have let a couple of people compare 
the codecs.

All persons what have tested have told us that:
1. All of the people told us that G729 sounds worst of all
2. All of the people told us that iLBC sounds good
3. All of the people told us that G711 sounds good
4. Most of the people told us that G711 has the best sound
5. A few people told us that iLBC has the best sound

...

So I have a different opinion about iLBC then you. But this is just a 
personal opinion :) At least I will always use iLBC instead of G729 
where possible.

>> I am using ilbc and I would like to see it in asterisk core. It is
>> pretty annoying to compile it manually every time...
> People complain about the CPU load of the open source iLBC. If you are a
> serious user, have you ever looked into whether someone might speed it
> up for you?

I think that you are right here. I am just a hobbyist in the Asterisk 
area and my "productive" Asterisk systems have never more that 3 
simultanios calls :)

Optimization of the codec might be pretty usefull but having an option 
for ilbc transcoding in asterisk core without manuall compilation is 
usefull too.

Regards, Artem

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