wiki:audio-check-rx-rtp

Checking if RTP Packets are Received

Use pjsua's dq (dump quality of current call) command from pjsua's menu to check that RTP packets are indeed received by pjsua. Use this command after the media is established, of course.

Also make sure that current call selected is the call that you want. You can change current call with ] and [ command.

Once correct call is selected and media is established, you can invoke dq command like below:

>>> dq
 14:54:37.008        pjsua.c
  [CONFIRMED ] To: sip:user@localhost;tag=1857bde149264e2986c4aac1a26f5866
    Call time: 00h:00m:53s, 1st res in 1071 ms, conn in 1191ms
    #0 speex @16KHz, sendrecv, peer=192.168.0.66:4000
       RX pt=103, stat last update: 00h:00m:01.753s ago
          total 1.7Kpkt 72.2KB (127.2KB +IP hdr) @avg=10.6Kbps
          pkt loss=0 (0.0%), dup=0 (0.0%), reorder=0 (0.0%)
                (msec)    min     avg     max     last
          loss period:   0.000   0.000   0.000   0.000
          jitter     :   0.000   5.506 227.000   9.812
       TX pt=103, ptime=20ms, stat last update: 00h:00m:07.871s ago
          total 0pkt 0B (0B +IP hdr) @avg 0bps
          pkt loss=0 (-1.$%), dup=0 (-1.$%), reorder=0 (-1.$%)
                (msec)    min     avg     max     last
          loss period:   0.000   0.000   0.000   0.000
          jitter     :   0.000   0.000   0.000   0.000
      RTT msec       :   0.274   0.616   1.233   1.233

Pay attention to this part of the report:

       RX pt=103, stat last update: 00h:00m:01.753s ago
          total 1.7Kpkt 72.2KB (127.2KB +IP hdr) @avg=10.6Kbps

as it shows the number of RTP packets received since the media is established.

Make sure that the number makes sense for the duration of the call (without VAD, normally we'll have about 50 packets received per second).

If the number is zero, then we're not receiving any RTP packets. There could be problems with the network, or NAT, or firewall, or something else, which is not related to the sound device.

If the number is too low, it's possible that remote is transmitting silence frames, which of course will be rendered as silence in the speaker.

What to do if no RTP packet is received

If no RTP packet is received, then probaby NAT is your enemy. The sound-problems/Getting_Around_Nat page describes some solutions to make the application works behind NAT.

Last modified 2 years ago Last modified on Jan 23, 2017 3:43:24 AM