0 votes


i paid for g729 codec on iphone, but i can not use it - if i select just this codec to force its use, the other phone starts ringing, and when the recipient answers, the call is interrupted and finishes. When I switch to GSM codec with the same setup, the call is established correctly and is OK.

However I want to use this paid codec for saving mobile data. And yes, my SIP provider is compliant with g729 codec.

Any ideas?

Other issue is that loudspeaker on iphone does not work - if i switch to phone loud speaker, the call is silenced or distorted (but continues) and it is not possible to swith back to the phone speaker.

My audio settings are:

Echo cancellation - Hardware

Automatic gain control - Hardware

Noise surpression sw - ON, Dialpad sounds - ON, Ring while Talking - ON

in iOS by (120 points)

Can you advise on the Zoiper version you are running on your device?

Also, try to use the Software settings for the Echo cancellation and Auto gain control.


at present it really seems that the problem is on side of my VOIP provider. I asked them to check it and they confirmed some transcoding issues on their server. The problem is being analyzed right now.

I tried switching to software but the issue was not fixed. Waiting for feedback/correction from my VOIP.

But thank you for advice!


Hi Ivan,

I confirm that the first issue (g729 codec) was resolved by my VOIP. What about the second issue regarding loud speaker?

I tried loud speaker today and it did not do anything, ie the call continued as if it was not switched to loudspeaker (at least the call was not distorted or did not crash). I have installed latest version of ios and latest version of Zoiper, (3.14). Audio settings are the same as described in first post.

PS: just tried also software echo and gain control, no change regarding loud speaker malfunctionality. 

Any ideas?

Have a nice day!

1 Answer

0 votes

To be able to use the G.729 codec, your VoIP service provider will also need to support it, depending on their setup the remote side of the call might also need to offer support for G.729.

For additional information and assistance, you should contact your VoIP service provider.

by (34.3k points)
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