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<body><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="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><hr id="stopSpelling">> 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 /><hr />Connect to the next generation of MSN Messenger <a href='http://imagine-msn.com/messenger/launch80/default.aspx?locale=en-us&source=wlmailtagline' target='_new'>Get it now!</a></body>
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