[asterisk-bugs] [JIRA] (ASTERISK-25247) choppy audio when spying on a g722 channel

[hristo (JIRA)]

hristo created ASTERISK-25247:
---------------------------------

             Summary: choppy audio when spying on a g722 channel
                 Key: ASTERISK-25247
                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-25247
             Project: Asterisk
          Issue Type: Bug
      Security Level: None
          Components: Applications/app_chanspy
    Affects Versions: 11.18.0
            Reporter: hristo


I get choppy audio when spying on a channel, which uses G722. The problem is very easy to replicate with the default asterisk configuration:

- Add {{allow=g722}} to the {{\[general\]}} section in {{sip.conf}}
- Add {{exten => 100,1,ChanSpy()}} in the {{\[demo\]}} context in {{extensions.conf}}
- Configure a phone with G722 only and dial "2" to listen to the demo instructions.
- From another phone dial "100" to spy on the first channel. The spying channel hears the extension announcement just fine. Then the choppy audio starts as soon as the spying channel gets bridged to the first call.

A PCAP capture confirms the audio problems on the spying channel. Initially Asterisk sends one packet of audio every 20 ms (this is the extension announcement prior to spying) then is starts sending one packet every 40-60 ms (starts at packet 1163 in the attached PCAP). It is almost as if it skips every other audio frame. The packet sequence numbers and timestamps however are all correct.

The problem is only present if the spied channel uses G722. The codec of the spying channel doesn't matter.

This happens on normal calls too. I am only using the demo instructions announcement here for simplicity.

The problem is not present on asterisk 1.8.x. I am unable to test with any of the newer versions though.

Attaching 3 files:
- g722-spy-choppy-audio.pcap:
-- 172.19.4.238 - Asterisk
-- 192.168.28.135 - Call 1 (G722)
-- 192.168.28.113 - Spy channel
- g722-spy-choppy-audio.log - asterisk debug log
- g722-spy-choppy-audio.au - audio extracted from the pcap capture file that demonstrates the problem.



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