similar to: preprocesssor questions

Hi, I have been looking at the speex library and I like it a lot. Good job! I have a couple of questions regarding the preprocessor: 1) I looked at the source code. Even though I am an experienced programmer it looks like Chinese to me ;-) What would I have to do to modify / tweak the audio processing code for my needs? Are there documents describing the algorithms applied for AGC, NS and VAD or

My data is speech sampled as pcm mono 32khz. I want to use vad for regulating the agc gain mechanism. So... if voice is not detected I just reduce the agc value in order to not amplify the 'silence' otherwise we just increase the agc value if it is below the minimum. Thanks, Daniel ----- Original Message ----- De: Jean-Marc Valin <jean-marc.valin at usherbrooke.ca> Para: danflu at

Hi Jean Marc, I found that the AGC API and algorithm has changed in svn head trunk. Is it safe to use it? Or is it for testing purpose only? You also said that VAD in svn is broken in a previous post, is it related to the AGC change? or can we mix the old VAD algorithm with the new AGC safely? kind regards, fredo

agc_gain seemed to fit with the idea of what I wanted to do, it was easy to understand its units and behavior, and freezing it produced the desired results. Also I wanted to cap it, so that's done at the same place, and that definitely works. All I want to do is be able to freeze AGC adaptation and put an upper bound on the AGC (for example, 2x amplification). Both of these things seem

> I hate to be a talker and not a do-er, but I won't be able to write this > myself, probably someone on the iaxclient team could do it. Anyway, let me know if/when someone's working on that. >> Hmm, or does that mean the analogue AGC is actually completely >> independent from the "real" AGC. Any thoughts? >> > > It's actually a bit more

I'm attempting to use speex preprocess for automatic gain control in an application I'm working on and could use some help. I'm using Opus as my codec. In order to keep the number of packets down, I'm using 60msec frames. I'm sampling at 48KHz as is recommended for Opus. So, the frame length is 2880 samples and the sampling rate is 48000. The source of the data is a

Hello, in my project im using speex 1.2rc1 and the preprocessor VAD seems to only separate complete silence from not complete silence frames. The Speex Manual, you can read "The voice activity detector (VAD) provided by the preprocessor is more advanced than the one directly provided in the codec." but if you go to the source code in preprocess.c line 995 "/* FIXME: This VAD

>> Yes, after I stop speaking, the noise slowly starts climbing again, and >> if I peek at st->agc_gain, that's slowly climbing too. I think part of >> the trouble is that the noise in here isn't uniform white noise; there's >> traffic outside the window and people walking in the hallway outside my >> door. Each little event is enough to cause the AGC

First, I'd just like to thank the Speex community, and Jean-Marc especially, for their great work. I'm developing a VoIP library (which uses IAX, the asterisk protocol) as the network protocol. I've been putting off integrating Speex for a while, as things have been working pretty well so far with GSM. (for those interested, the code is at iaxclient.sourceforge.net). However,

Jean-Marc Valin wrote: >> gcc version 3.4.5 (mingw special) > > Can you try 4.0 or 4.1 just to be sure? mingw (native gcc for win32) doesn't officially support using gcc 4.0 and 4.1 yet (apparantly there have been some issues), so there are no binary packages. But if you think it helps, I can compile gcc 4.1 and give it a shot. >> Compile flags: >> DEFINES +=

> As you can tell, the AAGC integration with speex was really a classic > hack. Instead of re-creating the hack, what's probably best here is to > integrate AAGC back into speex, and have a proper API. Agreed here. If you can come up with a clean patch to add that feature, it's something I'd like to see in Speex. > For those of you just tuning in, what I call

I've been using Speex's AGC in my VoIP program with mixed results. One of the problems I had was: At the beginning of the call, if the user hadn't spoken yet and there weren't any background sounds for the AGC to lock on to, most of the time the AGC would almost immediately jump way up to 200x gain (the default max). This is undesirable and usually results in nasty feedback. If

Hi All, I am getting this error when i try to compile the "Linphone" package by typing----- make. please help me i am feeling very frustrated with this error pasdt from 7 days i am getting this error. please help me. speexec.c: In function `speex_ec_process': speexec.c:112: `spx_int32_t' undeclared (first use in this function) speexec.c:112: (Each undeclared identifier is

There are many ways to implement a VAD. What you described is actually perfectly equivalent to the most trivial (and least robust) VAD algorithm. Jean-Marc Andy Ross wrote: > Ton Grandgent wrote: >> Andy Ross wrotte: >>> I wrote a trivial squelch feature* in 10 minutes that works >>> basically 100% of the time. >> Could you please explain how this differs from

Yes, you can use it independently by using speex_preprocess(). This function can do noise removal, AGC, and VAD. I've been using it to do all three and it usually works very well. There can be a train going by outside, producing lots of sound that makes it through the noise filter, and yet the VAD knows it's not speech. However, sometimes the VAD seems to get into a bad state and

Hi all: I was analysising the speex code these days and learned much from it. Thank you so much! But I have a question about VAD: After preprocess(denoise and agc are off, vad is on),the input pcm speech was distorted seriously.The input speech include ten syllables(one~ ten), but the output speech lost one! Can you tell me why? Please see the attachment about input and output: (See attached

I'm having trouble with the preprocessor's noise reduction feature. The basic issue is that it simply doesn't work very well. With my laptop (whose microphone is otherwise quite capable) I routinely hear transient background noise, typing, and other "quiet" sounds leaking through to the speex stream. Even worse, the AGC feature is blowing these things up into just awful

Hello there! our company (e-learning) is trying to roll out Mumble for our users. The quality is awesome but setting up the program is a pain for our users and we'd like to improve that for our users and for Mumble users in general. The main issue our users have is with voice detection. Speaking with Mumble's community they informed me Now, one of the most twitchy aspects of the audio

I think you'll have to modify Speex to get the functionality you're looking for. I've made a few simple modifications to the AGC to prevent it from 1) exceeding a specified level of amplification and 2) enable and disable adaptation, so I can freeze it at a certain level while speech is not detected. It's mostly just a matter of doing this at the end of speex_compute_agc():

Jean-Marc Valin escreveu: > > Well, I can change the defaults and then people with different setups > (e.g. no noise and low input volume) will ask me to change it the other > way... In the end, the only fix is to improve the AGC adaptation > decision, including (but not only) the VAD. Could that be a run time variable? So it could be adjusted somehow by a user interface, for