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PCMA codec issues on mobile app


RichardDCG
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There seems to be an issue with calls in Australia with codec mismatching - we use PCMA as the priority codec.  PBX V 68.0.2, iOS app V 1.15 (52)

 

On inbound calls - 

If I have the trunk set to have PCMA as priority and an extension on WIFI the codecs are matched at PCMA from ext. and PBX.

If I have the trunk set to have PCMA as priority and an extension on 4G the codecs are mismatched at PCMU from the extension and PCMA from the PBX.

If I have the trunk set to have PCMU ONLY and an extension on 4G the codecs are mismatched at PCMU on PBX and PCMA on ext. ??  ...... something weird happening here!

If I have the trunk set to have PCMA ONLY and an extension on 4G the codecs are matched at PCMA but the ext. drops the audio after a short initial start.

 

There was an earlier issue with call quality using PCMA that seems to have been resolved in the latest app... 

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Generally speaking, u-law and a-law are very similar and there is a lossless conversion between the codec that does not take much CPU, its just a table lookup. So it's not a big problem if the PBX has to transcode between them (transcoding between e.g. OPUS and G.711 is an entirely different story in terms of CPU and also audio quality losses). It's even possible that one direction is u-law and the other direction is a-law. As long as it sounds good, I would not worry too much about it.

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Hmm on the app it should work with the 1.15 version. However on the trunk side I would not be so sure. Many trunk providers have problems with different codecs. Because of that there are various settings, e.g. answer only with one codec in the SDP answer or just set the trunk to use only one codec.  

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Hello me too I noticed a problem during a call between Android and iOS application from time to time the sound does not play on one side or the other. The sound passes only on one side. But this problem already existed in version 67. I tried to force the negotiation in g711u between the pbx and the softphone extension the problem seems less regular ... In France I see improvements but we are far from 100%

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