We are using Envivio to stream the video(H.264) and audio(Mpeg-4 HE-ACC) to Wowza server through RTMP. And then generate the HTTP for IOS devices and RTSP for 3GPP devices. The problem is when playing the stream in 3GPP device, the audio become a machine sound. There is no problem for IOS devices. i have already add the following code in the Application.xml. But still the same.