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...e the manual is the right place. Anyway, out of all the challenges in constructing a VoIP system, it seems echo cancellation is easily the most difficult. But it's also extremely valuable functionality. So these issues will just keep coming up. Tom "Coffey, Michael" <mcoffey@avistar.com> wrote: > > Millions of ordinary people have systems that do not meet your stringent specifications. > > It does not matter what OS you or I use. It's the customers for whom this work is done. > > -----Original Message----- > From: Jean-Marc Valin [mailto:Jean-Mar...

...omers for whom this work is done. -----Original Message----- From: Jean-Marc Valin [mailto:Jean-Marc.Valin@USherbrooke.ca] Sent: Monday, July 02, 2007 6:35 PM To: Coffey, Michael Cc: speex-dev@xiph.org Subject: RE: [Speex-dev] Backup Echo Suppression Selon "Coffey, Michael" <mcoffey@avistar.com>: > Believe me; I've "played with" priorities and buffering. Then either you haven't played well enough or you're using a braindead OS. > Did you just say you have no idea how the Speex residual echo suppressor > works? If that is the case, can you tell me wh...

Believe me; I've "played with" priorities and buffering. Did you just say you have no idea how the Speex residual echo suppressor works? If that is the case, can you tell me where I could get some information about it? -----Original Message----- From: Jean-Marc Valin [mailto:jean-marc.valin@usherbrooke.ca] Sent: Friday, June 29, 2007 7:38 PM To: Coffey, Michael Cc:

Selon "Coffey, Michael" <mcoffey@avistar.com>: > Believe me; I've "played with" priorities and buffering. Then either you haven't played well enough or you're using a braindead OS. > Did you just say you have no idea how the Speex residual echo suppressor > works? If that is the case, can you tell me wh...

It appears that both the echo canceller and the noise reducer (NR) introduce rather severe clicking artifacts when presented with audio that has slightly overloaded the A/D converters. I am talking about speech that sounds just slightly distorted, due to clipping, when simply played back. If I pass that speech through the echo canceller or the noise reducer, it acquires really loud clicks and/or

On Jul 2, 2007, at 7:34 PM, Jean-Marc Valin wrote: > Selon "Coffey, Michael" <mcoffey@avistar.com>: >> Believe me; I've "played with" priorities and buffering. > > Then either you haven't played well enough or you're using a > braindead OS. This is sort of what I was talking about with nibbling. Imagine you have a microphone sampling at 128 samp...

Do you know of anyone, especially in the free software world, who has successfully tackled the problem of synchronizing real-time input and output audio streams of different devices using Windows? I need to do a good job of this so that Acoustic Echo Cancellation can work in my Video Conferencing application. I need to be able to capture audio from a USB webcam and play it out over the user's

The speex manual says: "It is recommended to use a frame size in the order of 20 ms (or equal to the codec frame size) and make sure it is easy to perform an FFT of that size (powers of two are better than prime sizes)." What is the impact of using a non-power-of-two frame size here? Since 20 ms of 8000 (or 16000) is not a power of 2, I have to make a choice. It would be most convenient

Do you have specific plans for producing a stable release of version 1.2? I work for a company that would like to use speex AEC in a product. I think my bosses would be concerned about using a library that is labeled as "beta" and "unstable." In the spirit of cooperation, I would be willing to assist the effort in any way that I am able. Thanks Again

Svn Log is my favorite! (Butm generally with the Tortoise front-end FWIW. I don't think I've changed anything except back when we needed the AEC patch or to make a project file build. -----Original Message----- From: Jean-Marc Valin [mailto:jean-marc.valin@usherbrooke.ca] Sent: Monday, June 11, 2007 4:27 PM To: Coffey, Michael Cc: speex-dev@xiph.org Subject: Re: [Speex-dev] RE: Moving

Has it been a whole week since a question about VAD? :-) I am curious why the VAD algorithm described in G.729 Annex B is not used by Speex. Complexity, Patent, Quality, or what? -mjc

Here's a question that may seem strange. Does the echo canceller maintain some data structure that I might be able to use if I wanted to estimate the amount of delay between the near-end and far-end signals? I'd like to be able to do this in order to optimally align the signals before passing them to the canceller. There seem to be many milliseconds of latency in a Wintel audio subsystem

Following up on the original topic of synchronization between the local mic and local speaker streams: We can separate this problem into two sub-problems: (1) compensating for differences in sampling rates; and (2) compensating for delay between the two streams. For estimating the delay, what do you think of the idea of using cross-correlation? -mjc -----Original Message----- From: Jean-Marc

Aha. By "frames" I assume you mean 10ms or 20ms or whatever I have passed as frame_size to speex_echo_state_init. Correct? (I suppose I could go to a smaller frame size if desiring finer precision.) I gather that prop[] contains proportional adaptation rates. I guess I'll have to read up on the MDF algorithm to get a better sense of what that means. Thanks -----Original

Since you asked for comments... Personally, I'm disappointed to see Speex moving to Git from Subversion. I had just recently learned how easy it is to track progress of Speex using TortoiseSvn. That being said, I'm sure Jean-Marc knows best what the issues may be. How many people are expected to commit on this project this year? -mjc

Terrific! The patch fixes my problem quite decisively. I will want to use this with a 16K sample rate. Is it expected to work well with just another slight patch, or will we need to modify it more deeply? Also, are there any tunable parameters besides tail length? I am wondering about the aggressiveness of adaptation and I know you are an expert in that area. Thanks so much, Michael

What is the current status of the residual echo suppressor in the preprocessor? I ask this because I have occasional problems with the AEC, in which it fails to cancel echo. I think the problems have to do with samples being dropped by the audio IO system, which is effectively impossible to detect and counteract reliably. A colleague recommended using an echo suppression technique (which he

I realize that the preprocessor echo suppression is not designed specifically to counter the effects of data loss. On the other hand, as much as I might like to, I do not have the option to "fix that problem for real." The sad truth is that some end users have systems that may drop samples, or do other unfathomable things, no matter what I do. I can not rewrite their drivers, firmware,

Hi Folks, I am having trouble using speex_echo_cancel. As a starting point, I am using the testecho.c source code. I compiled the 1.2beta1 version. I have not tried any other versions of speex. The document says that the order of arguments to Speex_echo_cancel is (echo_state, input_frame, echo_frame, output_frame, residue) where "input_frame" is as captured from mic and