Silk codec between 2 BRIA clients

[mda]

Hi,

I have 2 bria sip clients on iphone that support the silk and silk HD codec. It seems the best codec currently available.
I want to use this while both are registered on the 3cx server. I know that 3cx does not support the silk codec, but I think as long as I have 2 clients and pbx delivers audio is not enabeled it should work (The normal codecs like g722 and g711 work fine between the 2 clients)

However 3cx seems to force an other codec to the iphone bria clients eg g722 or g711. When I disable these in the bria sip clients so that only the silk codecs are allowed by the bria sip clients I get an error 406 (not acceptable)

Attempt to reach <sip:10@XXXXXX;user=phone> failed. Reason: Not Acceptable HereReason Unknown
Call to sip:10@XXXXXX has failed; Cause: 406 Not Acceptable; from IP:XXXXXXX:62745

Can somebody help. I figured that pbx delivers audio is not enabeled and reinvite is enabeled shoud do the trick but unfortunatly not.

 

[leejor]

I think as long as I have 2 clients and pbx delivers audio is not enabeled it should work

Well, what we want to work, and what actually does, might two different things.

I suspect that what is happening, in very simple terms...

When 3CX attempts a call to the extension and the extensions "replies" this is the Codec I want to use, 3CX being unable to comply, drops the call. I have doubts that it will get to the point that the Codec incompatibility will be ignored and two devices will be connected directly

Now, there may be a way around this by tweaking 3CX internally, or tricking it, but don't hold your breath, you may have to settle for using G711.

 

[mda]

I think you have a good point. I received the answer below from Bria in the mean time:

If the server doesn't mention SILK in its codec negotiation phase, it won't work, even if the clients bypass the server once they start sending audio. The server is still negotiation the connection between the two.

You'll have to find a way to add SILK support, or spoof it in the SDP, from the 3CX server. I'm sure there are resources online that detail ways to solve this issue.

Does anybody know if it is possible to spoof silk in the SDP of 3CX and if yes how.

 

[SY]

in bypass/proxy audio delivery mode, PBX does not alter codec and media descriptions.
Make wireshark capture of the call on server and post it here. It will hightlight all problems.
It is interesting to check it.

Thanks

 

[mda]

in bypass/proxy audio delivery mode, PBX does not alter codec and media descriptions.
Make wireshark capture of the call on server and post it here. It will hightlight all problems.
It is interesting to check it.

Thanks

Yes and correct me if i'm wrong, but isn't 3cx not the media who negotiates the codec between the clients. I think if 3cx would allow silk, it would work, transcoding the codec is not neccesery if both clients support the same silk codecs. I installed asterisk for a trial that does support the silk codec, and it works. The silk24 codec really sounds great. If 3cx would just negotiate this codec between the clients it woudl be great. I think it's the best codec available looking at sound quality. Especially if you take the needed bitrate in mind.