[Asterisk-Dev] G.722 and Grandstream

[Steve Kann]

Andrew Lindh wrote:

>I was playing with the BT-100 phone and G.722 this weekend. I added
>support to asterisk for G.722 calls and file format but I am having
>some trouble with the codec translation (it's in there but not working).
>
>The free example G.722 codec code I have does not seem to work with
>the G.722 data that I get from the grandstream. Does anyone know exactly
>what it is using or have some working C coded that works with their codec?
>Or at least some GOOD G.722 documentation so I can re-write the codec code.
>
>I have not tried G.722.1/G.722.2 which are not free (too bad).
>
>I have the codec showing up correctly and I can make SIP calls with G.722
>between supporting devices (I only have the grandstream)...
>
>The whole issue may be moot as I did not hear any real improvement since
>the BT100 phones are the cheapest toys...
>
>If I don't get any answers I'll still publish my G.722 additions without
>the codec translation, at least it will let people play with it.
>Internal transport is just the same as ULAW since it's the same data rate.
>  
>

You do realize that G.722 audio is 16kHz, and there's code all over 
asterisk that assumes 8kHz; even if you decode G.722, you still need to 
resample to get 8kHz, and to encode to G.722, you'll need to resample to 
16kHz. Then there's all the code that assumes that ms = samples/8, etc..

Not having seen any of your code, or any mention of the steps you took 
to account for this, I don't know if you've done the (somewhat large) 
amount of work necessary to overcome this barrier..

-SteveK