Originally Posted by alankeny
Thanks for confirming it's not just my phone.
As jjwatmyself points out, even at its best the native SIP client isn't that good. When I had it working on another phone on an earlier version of Android, it would often lose the SIP registration, and there was no way to tell there was a problem.
I think I'm going to put my energy into getting CSIPSimple working better. I'm having mic issues with it too, but it's not distorting the audio. I'm just having problems with dropouts and echo. There are enough settings to adjust in CSS, it should be possible to clear these up. I'll open a thread in the QA forum for that though.
I must confirm that native SIP client doesn't serve the real purpose. I tested it and I shall say that there is an obvious progress from 4.4 where you can obtain the connection but there wasn't any voice transmission. Now you have voice on both sides but as on the side of SIP client the voice is normal, on the other side is heavily disorted: it is choppy and harmonic frequences are added. In fact it is hard to understand and therefore native SIP is unacceptable for everyday use.
As there are other reports for different phones having the same issue with KItKat I believe that this is an Android's failure not Moto's. It seems that error occurs as mutual codec and echo cancellation absence failure. Hopefully it wil be solved in the next release as certain progress has been already made.
But I must say that CSIPSIMPLE works amazingly well for me. I set alaw as my primary codec and ulaw as next and disable all other codecs (first I checked with my voip provider wich codecs are supported). There is clear voice on both sides and first time ever since I've used voip, the jitter lag is acceptable what means that it doesn't cause the disturbing gap between listening the other side and speaking. I can recomend this program (I tried the others too but this one is the only without significant flaws) and hope for native SIP with 4.5.