[Freeswitch-users] channels not in sync on stereo recording

[Dave Horton]

I'm experiencing a strange problem on a recording of an audio stream 
where the two channels (I am recording in stereo) are not in sync.  By 
that, I mean when I play back the audio one of the tracks is somehow 
time-shifted, so that it doesn't match up to the proper place in the 
timeline with the other side.  For instance, if I call out to a bank 
IVR system that plays a prompt, and I barge into the prompt by pressing 
a DTMF key, on the recording I will hear the prompt start and then stop 
at the same place it stopped when I pressed the DTMF, but the DTMF key 
itself does not show up on the recording for 5 seconds more.  Has 
anyone ever heard of anything like this?

Now, a few more details.  I am creating a bridge conference and then I 
am recording the audio stream to and from the called party and the 
conference.  I do not have this problem if I record the audio stream to 
and from the calling party and the conference.

Here is the dial plan I am using:

    <extension name="6174973895" continue="false">
      <condition field="source" expression="mod_sofia"/>
      <condition field="destination_number" expression="6174973895">
                <action application="ring_ready"/>
                <action application="answer"/>
                <action application="start_dtmf"/>
                <action application="set" 
data="call_id=${strftime(%Y%m%d_%H%M%S)}_${sip_from_tag}"/>
                <action application="export" 
data="outfile=$${base_dir}/tmp/${call_id}.wav"/>

                <action application="lua" data="demo_call2.lua"/>

                <action application="export" data="RECORD_STEREO=true"/>
                <action application="export" 
data="nolocal:execute_on_media=record_session ${outfile}"/>

                <action application="export" 
data="nolocal:api_on_answer=conference ${call_id} play 
misc/this-call-may-be-recorded.wav async"/>
                <action application="conference" data="bridge: 
${call_id}@simple:{origination_caller_id_number=${caller_id_number}}sofia/normal_customer/${outdial}@${egress_gateway}"/> 

        </condition>
    </extension>

Any thoughts on what might be going on?