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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thank you very much Mathieu<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>So if TFLAG_IO is not set, read_frame will return immediately
and *frame is NULL ? Is it a normal behavior if the call is terminated when a
NULL frame is returned ? <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Coz when I return a NULL frame, the call is terminated. So now
my understanding is that if my endpoint buffer is empty, I need to return a
silence frame to the other end, right?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thank again Mathieu for your quick reply, that helps a lot </span><span
style='font-size:11.0pt;font-family:Wingdings;color:#1F497D'>J</span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Regards<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Alex To<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
freeswitch-dev-bounces@lists.freeswitch.org
[mailto:freeswitch-dev-bounces@lists.freeswitch.org] <b>On Behalf Of </b>Mathieu
Rene<br>
<b>Sent:</b> Monday, November 09, 2009 2:54 AM<br>
<b>To:</b> freeswitch-dev@lists.freeswitch.org<br>
<b>Subject:</b> Re: [Freeswitch-dev] Questions about read_frame and write_frame
events<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Hi,<o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>See answers inline.<o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif";
color:black'>Mathieu Rene<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif";
color:black'>Avant-Garde Solutions Inc<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif";
color:black'>Office: + 1 (514) 664-1044 x100<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif";
color:black'>Cell: +1 (514) 664-1044 x200<o:p></o:p></span></p>
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<div>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif";
color:black'><a href="mailto:mrene@avgs.ca">mrene@avgs.ca</a><o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif";
color:black'><o:p> </o:p></span></p>
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<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif";
color:black'><o:p> </o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>On 8-Nov-09, at 4:21 AM, Alex To wrote:<o:p></o:p></p>
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<p class=MsoNormal><br>
<br>
<o:p></o:p></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'>Hi,<o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'> <o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'>I am getting stuck on read_frame and write_frame in my custom
endpoint. Would someone shed some lights on how it works?<o:p></o:p></span></p>
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<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'> <o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'>My questions about read_frame, write_frame after reading mod_iax,
mod_portaudio and mod_skyiax are:<o:p></o:p></span></p>
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<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'> <o:p></o:p></span></p>
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<div style='margin-left:.5in'>
<p class=MsoNormal style='text-indent:-.25in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>1.</span><span
style='font-size:7.0pt;color:black'> <span
class=apple-converted-space> </span></span><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>Is it correct that I need to
check a flag (for e.g TFLAG_HUP) of the private object at the beginning
of the event to determine whether I should continue reading audio or just
return. The flag TFLAG_HUP is set when a hangup or kill channel event is
detected.<o:p></o:p></span></p>
</div>
</div>
</div>
</blockquote>
<p class=MsoNormal>Thats what TFLAG_IO is for, clear the flag the read_frame
functions should return immediately.<o:p></o:p></p>
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<div>
<p class=MsoNormal>If you catch TFLAG_BREAK, on the other side, you should
clear it and return a comfort noise frame ( cng )<br>
<br>
<o:p></o:p></p>
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<div>
<div style='margin-left:.5in'>
<p class=MsoNormal style='text-indent:-.25in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>2.</span><span
style='font-size:7.0pt;color:black'> <span
class=apple-converted-space> </span></span><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>Read_frame is called on an
interval (how frequently is the interval ? how do I determine that?) to read
audio from my endpoint.<o:p></o:p></span></p>
</div>
</div>
</div>
<p class=MsoNormal>It depends on the codec you are using, if you are using 20
packetization time, it'll be called every 20ms.<br>
<br>
<o:p></o:p></p>
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<div>
<div style='margin-left:.5in'>
<p class=MsoNormal style='text-indent:-.25in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>3.</span><span
style='font-size:7.0pt;color:black'> <span
class=apple-converted-space> </span></span><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>What is TFLAG_IO normally used
for ?<o:p></o:p></span></p>
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</div>
<p class=MsoNormal>See point 1<br>
<br>
<o:p></o:p></p>
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<div>
<div style='margin-left:.5in'>
<p class=MsoNormal style='text-indent:-.25in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>4.</span><span
style='font-size:7.0pt;color:black'> <span
class=apple-converted-space> </span></span><span class=apple-style-span><span
style='font-size:11.5pt;font-family:"Calibri","sans-serif";color:black'>What is
the label “cng” is all about ? May I know what “cng”
stands for and how it is used?</span></span><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'><o:p></o:p></span></p>
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</div>
<p class=MsoNormal>CNG stands for Comfort Noise Generation, whenever read_frame
jumps there, it returns a frame of silence. It it first initialized on
private_t since its pointless to re-allocate empty frames.<br>
<br>
<o:p></o:p></p>
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<div>
<div style='margin-left:.5in'>
<p class=MsoNormal style='text-indent:-.25in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>5.</span><span
style='font-size:7.0pt;color:black'> <span
class=apple-converted-space> </span></span><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>What if read_frame is called
while my end point is not ready to send any audio yet?<o:p></o:p></span></p>
</div>
</div>
</div>
<p class=MsoNormal>That's why you set TFLAG_IO whenever you are ready. Also
note that it wont be called until you either pre_answer (go in early media) or
answer the channel.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>When a call is made, switch_ivr_originate() doesn't return
until your endpoint is ready to exchange audio.<o:p></o:p></p>
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<div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<div>
<div>
<div style='margin-left:.5in'>
<p class=MsoNormal style='text-indent:-.25in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>6.</span><span
style='font-size:7.0pt;color:black'> <span
class=apple-converted-space> </span></span><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:black'>What is the
tech_pvt->cng_frame is used for? I notice that the *frame is set to
tech_pvt->cng_frame if the label “cng” is reached.<o:p></o:p></span></p>
</div>
</div>
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</blockquote>
<p class=MsoNormal>See point 4.<br>
<br>
<o:p></o:p></p>
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<div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'> <o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'>Thank you very much for even reading my questions. I tried to look
for documents that explains clearly the above questions but so far no luck.
Until now I still don’t have a clear understanding about these 2 events
yet.<o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'>Best Regards<o:p></o:p></span></p>
</div>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'> <o:p></o:p></span></p>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:black'>Alex To<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><span style='font-size:13.5pt;font-family:"Helvetica","sans-serif";
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