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<body>All, <BR>
<BR>
Wonder why all my posts has no line breaker when it displayed the forum... I used Hotmail(Windows Live Mail) <BR>
with FireFox 2.0. I am posting this msg with IE 7.0 and see if it make any difference. Anybody experienced the<BR>
same issue and how to workaround it?<BR>
<BR>
Thanks a lot! <BR>
<BR>
Regards,<BR>
William <BR><BR>
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From: espzzh@hotmail.com<BR>To: jean-marc.valin@usherbrooke.ca<BR>CC: speex-dev@xiph.org<BR>Subject: RE: [Speex-dev] Performance of the acoustic echo canceller<BR>Date: Tue, 6 Mar 2007 01:39:11 -0800<BR><BR>
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<DIV style="TEXT-ALIGN: left">Hi Jean-Marc, <BR><BR>Thanks for the suggesting. I tried the test wtih my recording file offline through the testecho. <BR>I got the same result(no prepocessor echo suppression) as my recording file for that live call. <BR>Basically I don't see the difference between input_frame and output_frame. <BR><BR>As I mentioned in my original post, the echo return loss is about 20db. I guess the echo canceller<BR>is not really actively cancelling the echo in such condition? But without the echo sppression/NLP, echo is <BR>still noticable. I used the same onboard sound card for the speaker and microphone. As far as I <BR>can tell, the delay between echo_frame and input_frame is consistent and about 10ms. I would assume<BR>the synchronization is not a problem. <BR><BR>And I also have some other echo recording files which has almost 0db echo return loss and about 20ms <BR>consistent delay. The EC can achieve about 10 to 15db echo return loss enhancement in this case. <BR>Is it normal? I would think 25+ db ERLE plus 15+ NLP/ES should make the residual echo inaudible. <BR><BR>I am not sure about the nonlinearity of those recording files but I would appreciate it if you could take a look <BR>of those. I uploaded them to <BR><A id=EC_downloadhref href="http://www.sharebigfile.com/file/101511/capture-zip.html" target=_blank>http://www.sharebigfile.com/file/101511/capture-zip.html</A><BR>Capture1.zip is first case, 20db ERL. Capture2.zip is second case, 0db ERL. <BR><BR>Bunch of thanks! <BR><BR>Regards,<BR>William<BR><BR></DIV><BR><BR><BR>
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> Date: Mon, 5 Mar 2007 20:27:39 +1100<BR>> From: jean-marc.valin@usherbrooke.ca<BR>> To: espzzh@hotmail.com<BR>> CC: speex-dev@xiph.org<BR>> Subject: Re: [Speex-dev] Performance of the acoustic echo canceller<BR>> <BR>> Best advice I can give is to record the near-end and far-end files, pass<BR>> them through testecho (disable the preprocessor) and check the result.<BR>> Then check why it's not working (if that's the case). Some usual suspects:<BR>> <BR>> 1) Clock drift between capture and playback<BR>> 2) Bad synchronisation<BR>> 3) A non-linearity somewhere (bad speakers, noise gate, ...)<BR>> <BR>> If you try everything and can't find what the problem is, please upload<BR>> the files somewhere and send an email with the links (do not email the<BR>> files directly).<BR>> <BR>> Jean-Marc<BR>> <BR>> William Zhang a écrit :<BR>> > Hi All, I am working on my master project to port the Speex Acousic<BR>> > Canceller to FPGA. But I am not able to get a satisfied result in its<BR>> > performance whenI integrated it to a SIP softphone as my first step.<BR>> > The SIP softphone calls to a PSTN gateway and lands to my land line<BR>> > phone. I can hear the echo of my every word while I talks on the<BR>> > land line phone. I am using G.711 codec, frame_size 80 and both<BR>> > 1024 and 2048 tail length. The code was compiled as floating point<BR>> > and fixed point in the PC. But noneof them help. I made sure the the<BR>> > synchronization between echo_frame and input_frame was stable and the<BR>> > delay is consistant about 10ms. The echo return lossis around 20db<BR>> > but output_frame and input_frame signal is about the same. I even<BR>> > tried Jean-Marc's latest mdf.c from the subversion but no luck. Has<BR>> > anyone test the performance in any other softphones and how well does<BR>> > it work? I have the recording files, anyone would be interesting in<BR>> > taking a look? I wonder if there is something wrong with my input,<BR>> > setup...BTW: did anyone ever try to port the algorithm to hardware?<BR>> > I will do some profiling and implement the most compuation expensive<BR>> > function in the Xilinx FPGA.I would really appecriate if anyone can<BR>> > share some experience or provide adavise and suggest! I like to<BR>> > contribute my work to the Speex project if my project turns out to be<BR>> > good end. Regards,William <BR>> > _________________________________________________________________ <BR>> > Connect to the next generation of MSN Messenger <BR>> > http://imagine-msn.com/messenger/launch80/default.aspx?locale=en-us&source=wlmailtagline<BR>> > <BR>> > <BR>> > <BR>> > ------------------------------------------------------------------------<BR>> > <BR>> > <BR>> > _______________________________________________ Speex-dev mailing<BR>> > list Speex-dev@xiph.org <BR>> > http://lists.xiph.org/mailman/listinfo/speex-dev<BR><BR>
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