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<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Mohammed
Sulaiman [mailto:mhh.sulaiman@talk21.com] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, February 11, 2008
12:53 AM<br>
<b><span style='font-weight:bold'>To:</span></b> Dennis Liu<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [Speex-dev] Echo
Canceller on Windows Mobile</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hi, thanks. One question did you use these 2 functions <o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>speex_echo_playback</span></font><font size=2><span
style='font-size:10.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>speex_echo_capture</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 color=navy face="Times New Roman"><span
style='font-size:12.0pt;color:navy'>No, I didn’t use them. I use my own
code to buffer microphone and speaker data.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>or do you have your audio in a single thread</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>and use </span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 color=navy face="Times New Roman"><span
style='font-size:12.0pt;color:navy'>Yes, I have my audio thread.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>The AEC slows down our code real bad, i take it this where
the optimisation comes in. So far we have just used some of the PREPROCESSOR
definitions that come with the library. Are you saying we need to actually hand
optimise (modify)the code as well? Did you use assembly language for this?</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <font color=navy><span style='color:navy'>Definitely you have to
work on your own to optimize the code. I haven’t used assembly so far
since the efficiency on WM5/6.</span></font><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>Thanks</span></font><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
<b><i><span style='font-weight:bold;font-style:italic'>Dennis Liu
<dennis.liu@mobidia.com></span></i></b> wrote:<o:p></o:p></span></font></p>
</div>
<blockquote style='border:none;border-left:solid #1010FF 1.5pt;padding:0in 0in 0in 4.0pt;
margin-left:3.75pt;margin-top:5.0pt;margin-bottom:5.0pt'>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’ve worked on implementing Speex
AEC to smartphone on the exactly same platform as you have. The result is
pretty good. I can remove most of the acoustic echo. I’m still tuning the
performance to minimize the remaining echo. Here are the key points: <o:p></o:p></span></font></p>
</div>
<ol style='margin-top:0in' start=1 type=1>
<li class=MsoNormal style='color:navy;mso-list:l1 level1 lfo3'><font size=2
color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial'>You
have to sync microphone and speaker properly; otherwise it wouldn’t
give you a good result.<o:p></o:p></span></font></li>
<li class=MsoNormal style='color:navy;mso-list:l1 level1 lfo3'><font size=2
color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial'>You
have to optimize Speex AEC in order to run on mobile device in real time.<o:p></o:p></span></font></li>
</ol>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Regards,<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Dennis<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabIndex=-1>
</span></font></div>
<div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
speex-dev-bounces@xiph.org [mailto:speex-dev-bounces@xiph.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Mohammed Sulaiman<br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, February 08, 2008
7:55 AM<br>
<b><span style='font-weight:bold'>To:</span></b> Speex-dev@xiph.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Speex-dev] Echo
Canceller on Windows Mobile</span></font><o:p></o:p></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hi Jean Marc,<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>We are running the speex echo canceller code on a Windows Mobile
smartphone using a TI OMAP 201MHz 850. We are making voip calls and audio
is working without echo canceller code. Simply adding the following 2 functions
whether the echo cancellation is wired in (ie we use the output
frame ) or not performance becomes terrible. Note 2 separate
threads are used to handle audio.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Playing Audio thread:<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Write to codec<o:p></o:p></span></font></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>speex_echo_playback(echo_state, echo_frame);<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>Capturing audio thread:<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>Receive buffer<o:p></o:p></span></font></p>
</div>
<div>
<div>
<p class=MsoNormal><font size=2 face=Courier><span style='font-size:10.0pt;
font-family:Courier'>speex_echo_capture(echo_state, input_frame, output_frame);<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>We have compiled for fixed point.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>We are using codec buffer size of 256 bytes ie 128, 16bit samples.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>SpeexEchoState* iEchoState = speex_echo_state_init(ECHO_FRAME_SIZE,
ECHO_FILTER_SIZE);<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>ECHO_FRAME_SIZE = 128<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>ECHO_FILTER_SIZE = 1024<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Any ideas?<o:p></o:p></span></font></p>
</div>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Do you know whether any one has this running on Windows Mobile
platforms successfully.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Regards<o:p></o:p></span></font></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=1 width="100%" align=center>
</span></font></div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
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</blockquote>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=1 width="100%" align=center>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
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