How implement the VOIP application using android.net.rtp package

问题

I am trying to implemented the VoIP application using the AudioGroup and AudioStream classes of the android.net.rtp package. But my application not function properly. After "Join" the "AudioGroup" class object with the "AudioStream" object, its send udp packets successfully. I checked that using the packet analyzer. But voice is not hear from the phone. I run my application in 2 phones and try communicate voice between them.

In below I mention my source code.

public class MainActivity extends Activity {
private AudioStream audioStream;
private AudioGroup audioGroup;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

try {
   audioGroup = new AudioGroup();
   audioGroup.setMode(AudioGroup.MODE_NORMAL);        
   audioStream = new AudioStream(InetAddress.getByAddress(new byte[] {(byte)192, (byte)168, (byte)1, (byte)4 }));
   audioStream.setCodec(AudioCodec.PCMU);
   audioStream.setMode(RtpStream.MODE_NORMAL);
   audioStream.associate(InetAddress.getByAddress(new byte[] {(byte)192, (byte)168, (byte)1, (byte)2 }), 5004);
   audioStream.join(audioGroup);
   AudioManager Audio =  (AudioManager) getSystemService(Context.AUDIO_SERVICE); 
   Audio.setMode(AudioManager.MODE_IN_COMMUNICATION);
} 
catch (SocketException e) { e.printStackTrace();} 
catch (UnknownHostException e) { e.printStackTrace();} 
catch (Exception ex) { ex.printStackTrace();}
}

I set this permissions in the Manifestfile.

<uses-permission android:name="android.permission.USE_SIP" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-feature android:name="android.hardware.sip.voip" android:required="true" />
<uses-feature android:name="android.hardware.wifi" android:required="true" />
<uses-feature android:name="android.hardware.microphone" android:required="true" />

I am using the Samsung GALAXY S3 phone with Android 4.0 OS

回答1:

The trick is to get the port mapping correct. You need to use the port number from audioStream.getLocalPort() and send this port number to the peer in the SDP packet as SIP signalling.

Check out this example application which implements sip functionality https://github.com/Mobicents/restcomm-android-sdk/tree/master/Examples/JAIN%20SIP

回答2:

I used the same code you submitted, and got it working with minor changes. Basically i found the problem was getting the port number correct.

When creating the audioStream the port number seems to be random. At Android developer I found: Note that the local port is assigned automatically to conform with RFC 3550.

What I did was I started the application on one phone first and used audioStream.getLocalPort() to find the port number. Then I connected to this port using the other one. This resulted in two-way communication, even if i only had the correct port number on one phone.

Hope this helps.