Unnecessary Codec Transcoding

[Wunan]

Hello Experts

3CX system is unnecessarily transcoding the codec instead of negotiating. When a particular codec is present in both the leg of the call, transcoding is unnecessary. It should negotiate the codec If any of you guys have any solution to this, please let me know. I believe 3CX should find a fix to this issue.

In the image attached, the INVITE sent and the SDP received, both have the common codec of G711A, but the system is transcoding back and forth and sending G722 for one leg and G711A for the other leg.

Thank you

 

[SteveITS]

Ensure the SIP trunk and phones and apps all have the same codec order, or at least all use the same primary codec the trunk uses.

 

[Wunan]

That is how it is already there, except the SIP Trunk provider

This is when the codec negation plays the part. Even when the priority order is different, when there is a common codec is available on both the sides, system should use that instead of transcoding.

Transcoding is useful only when there are no common codec exist on both the sides.

 

[YiannisH_3CX]

Thank you for the feedback but this is the way it currently works. 3CX will tread call legs differently and will transcode the audio if necessary.
If this is causing issues for you with audio quality or server resources then I would recommend switching everything to G711A which your provider supports since you can control your phones and the server but you cannot control your provider.
Or if you are certain your provider supports G722 in all scenarios then remove all other codecs from the provider settings.

 

[Wunan]

Thank you for the feedback but this is the way it currently works. 3CX will tread call legs differently and will transcode the audio if necessary.
If this is causing issues for you with audio quality or server resources then I would recommend switching everything to G711A which your provider supports since you can control your phones and the server but you cannot control your provider.
Or if you are certain your provider supports G722 in all scenarios then remove all other codecs from the provider settings.

I know this is how it works because this is the only way it works at this moment. You are saying, "3CX will transcode if necessary", but my whole point here is that 3CX is transcoding unnecessarily.

We are unable to use High-Quality HD Voice Codec OPUS for internal calls and G711A for the trunk provider. Everything gets transcoded automatically, which is unnecessary when G711 exists on both legs as a common codec.

Please 3CX, give us the fix for this soon.

 

[YiannisH_3CX]

You still have not told us if you are facing any issues with transcoding though. Do you experience bad audio quality or you have complaints from users?

 

[Wunan]

Yes, when the number of calls increases.

 

[123doE8]

I know this is how it works because this is the only way it works at this moment. You are saying, "3CX will transcode if necessary", but my whole point here is that 3CX is transcoding unnecessarily.

We are unable to use High-Quality HD Voice Codec OPUS for internal calls and G711A for the trunk provider. Everything gets transcoded automatically, which is unnecessary when G711 exists on both legs as a common codec.

Please 3CX, give us the fix for this soon.

I have thought the same.
We have only recently rolled out 3cx across our school and i have set all IP phones to G722 codec to achieve HD voice but this does mean the external call leg is transcoded. I think it would make sense to negotiate a common codec in these scenarios allowing HD calls internal and automatically drop to G711 for external.

I haven't yet noticed any issues with the transcoding but just thought it would be best to avoid transcoding if possible. I understand best advice is to set codec priority to the same across all devices and sip trunks but this wouldn't enable HD voice internally for us.

 

[YiannisH_3CX]

Yes, when the number of calls increases.

Then you might need a higher spec machine.

Just to be clear I am not saying your scenario is not valid and what you are proposing is not useful. What I am saying is that this is how it is designed to work and its not an issue that needs fixing.
Your request is a feature request that belongs to the Ideas section.