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<div class=Section1>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Henry<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'>If I could provide a brief comment… I have found
many video conferencing software, including skype, do struggle with poor audio
and echo cancelling issues… That being said, some do work a lot
better than others.<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'>But it should be noted that I am a big fan on using superior
hardware to provide superior quality. <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'>Have you considered using any of the USB echo cancelling
speaker/microphone devices? See <a
href="http://www.accessgrid.org/test/taxonomy/term/23">http://www.accessgrid.org/test/taxonomy/term/23</a>
for some examples. I personally use the Chat150 and Chat50 devices and I
think they are great. They tend to work like a plug-a-play device, no
tweaking required.<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'>The great thing about these devices is that not only can they be
used within the AG (Across the different platforms [Windows, Linux and Mac]),
but can be used on a variety of other conferencing software, such as Skype,
EVO, etc.<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'>Now these devices are not as good as a proper fully blown AV
system, but in my opinion they work well and I have seen them deployed all over
the place.<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'>Anyway, hope you don’t mind me adding in my 2 cents worth.<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'>Thanks,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Jason.<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'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'>
<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> Henry Hernando Caballero Corzo
[mailto:hh.caballero921@uniandes.edu.co] <br>
<b>Sent:</b> Tuesday, 22 September 2009 02:38 PM<br>
<b>To:</b> ag-tech@lists.mcs.anl.gov<br>
<b>Subject:</b> [AG-TECH] RAT audio quality - Alternative codecs?<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Hi
everyone,</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Hope
you can advise me in the following issue.</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Scenario:</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Say
we're holding a videoconference which joins people from two different types of
nodes:</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>-A
conference room with an adequate AG node setup (audio equipment for echo
cancelling (ClearOne RAV 600), ambient microphone, high-end speakers, etc.)</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>-A
"casual participant" (an academic who joins the conference from his
workplace and uses his personal AG-equipped laptop sporting integrated
microphone and speakers)</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Then
a lot of -predictible- problems related to audio arise. Audio quality can
degrade so badly (enormous echo and noise) that ends up ruining the meeting. We
certainly know we're dealing with a "non-recommendable" scenario, but
the fact is, we need it to work.</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>First
question:</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>1.
How do you guys deal with this kind of setups? (if there's some way)</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Going
deeper in this issue, I -almost inevitably- turned my eyes on RAT. Even though
RAT works well under controlled setups, We certainly expect it to perform much
better when used in uncontrolled environments like the described above. So,
there're some more questions to ask:</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>3.
Is RAT lacking important features like: ultra-wideband sampling, echo
cancelling, noise suppression, active voice detection, discontinuous
transmission (among others) ?</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>4.
Or it's all about tweaking with RAT options? (some of the above features seem
to be included, not sure if they work well though)</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>5.
What about Speex[1] and/or SILK[2] codecs? Would it be feasible to integrate
these codecs to the Access Grid?</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>*
I'm aware of this development[3], which is part of a contribution from NCHC. It
involves the integration of Speex into RAT, but I'm really not sure if these
features are included in the current version of RAT that ships with the latest
AG release</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>*
SILK claims excellent voicecall quality and the truth is, Skype can in fact
deal with our "problematic setup" with absolutely no problem</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Thanks
in advance!</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>Henry
Caballero</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>----------------</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>AG
node administrator - Universidad de los Andes (http://ag-mox.uniandes.edu.co)</span></span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>[1] http://speex.org/</span></span><span
style='font-family:"Arial","sans-serif"'><br>
<span class=apple-style-span>[2] </span></span><a
href="https://developer.skype.com/silk"><span class=apple-style-span><span
style='font-family:"Arial","sans-serif"'>https://developer.skype.com/silk</span></span></a><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-style-span><span style='font-family:"Arial","sans-serif"'>[3] http://www.nchc.org.tw/en/core_content/download.php?FILE_ID=152</span></span><o:p></o:p></p>
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