similar to: Re: speex_denoise on non-microphone noise (static ?)

The problem started with speech detection. Speech sections are detected well. However, once in a while non-speech sections are also marked as speech. The root was finally traced down to microphone static noise. Then I pulled the microphone out. Our system still records noise. To isolate the problem, I wrote a small app just to open the device and record raw samples, calls speex_denoise()

Hi, I'm not sure how speex_denoise() works, but my solution to this problem is fairly straightforward and works well in practice (in a simple VoIP program.) Note that I am also an amateur and am making up some terminology here... but I've tested my approach on several noisy environments with low-quality mics and it does work well. Problem: There's usually annoying noise present

Take what I say with a grain of salt: I'm an amateur and haven't actually touched Speex in any way, yet. I'm just sort of passing on personal belief from personal experience. Also, check and make sure that the microphone line is insulated. There are a number of problems with sound cards picking up interference from the host machine. The wires that run between ICs on a card

Thanks for the speedy response and detailed, enlightening explanation. Now I understand where the problem is, and will try out your suggestions just to further confirm my conjecture. When I am done, I have to take the foil out, though. This is a product for our customers to use, and although we've got budget for mulffing every sound card we developers use, most likely the company

That's might be speex_denoise() is trying to do already, based on the fact that if noise is present in speech signal, the former gets suppressed to a certain extend. Also, I noticed after suppression, the short, noisy attack - speex_denoise() have to be doing some kind of profiling. I've looked at a few offline denoise() solutions. They all involve profile building. A real-time

Understand that it's a *guess*. If this fixes or at least betters the situation, you're going to need to find a legit way to insulate these cards, or to switch cards. If it's for customers, I should hope you wouldn't be using enamelled aluminum foil. :D -----Original Message----- From: Tongbiao Li [mailto:tli@viack.com] Sent: Thursday, September 18, 2003 11:20 AM To:

I'm not sure you'd have much success in trying to make a generic profile to fit the "typical noisy PC" since PC configurations vary so much. Consider an integrated AC97 codec vs. the mic input on an SB Live!/Audigy Live!Drive, or whether or not the input from the CD-ROM audio is muted, or what noisy devices might be situated near the mic. It's nice to be able to get

Hi, There seems to be some confusion as to how speex_denoise (now called speex_preprocess) works. Unlike what some here assume, the noise estimation is not done offline or while prompting the user. The system automatically adapts the noise estimate when it detects that the user is not talking. This also means that it is able to adapt to changing noise environments - as long as the noise is not

Hi, The leakage problem you describe is very, very common and you will need to do something to address it. I modified the version of Speex I use to implement an adjustable max gain. If you look at speex_compute_agc in preprocess.c, you will see: if (agc_gain>200) agc_gain = 200; This max of 200 is usually more than enough to amplify leakage which occurs either in the sound

Le dim 31/08/2003 à 20:12, Daniel Vogel a écrit : > > This works really well for white noise reduction. However > > what I've noticed was the amplitudes of normal speech samples > > also get reduced. > > Noticed this as well recently. This is probably due to the AGC (Adaptive Gain Control) that's integrated with the denoiser. I'll try adding an option to

Jean-Marc Valin wrote: >> I've had a small case with noise suppression and AGC. I have a fairly >> noisy environment here, and with the default parameters, noise >> suppression works fairly well while I talk. However, when I shut up, AGC >> starts slowly increasing the gain until it has amplified whatever noise >> is left to levels about equal to having no

This works really well for white noise reduction. However what I've noticed was the amplitudes of normal speech samples also get reduced. Is this something by design, or is there a way to automatically recover the original speech sample volumes ? <p>Thanks. <p>Tongbiao <p>-----Original Message----- From: Jean-Marc Valin [mailto:jean-marc.valin@hermes.usherb.ca] Sent:

Hi, I've had a small case with noise suppression and AGC. I have a fairly noisy environment here, and with the default parameters, noise suppression works fairly well while I talk. However, when I shut up, AGC starts slowly increasing the gain until it has amplified whatever noise is left to levels about equal to having no filtering at all. As soon as I talk, AGC backs down fairly quick

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

> 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 to increase a little

Just to let you know I released 1.1: This is an unstable release. It brings many new features, some of which are still experimental. The new features are: * a denoiser that removes most of the background noise and can be used before encoding (available as --denoise in speexenc) * adaptive gain control (AGC), which adjusts the volume to a constant level (available as

Hi, I am working on a VOIP implementation were one of the key design goals is zero user configuration. Similar to Skype. What I've come to notice is that my soundcard (NForce4 based) leaks audio from the playback path to the recording path. This is probably not unique for my hardware at all and will happen on some percentage of all users of my software. (All of this is Win32) What happens is

> So I have had a chance to delve deeper into the new pre-processing > code- I was also able to get VAD, AGC, Denoising, etc working inside of the > current release candidate (1.0.3). For some reason, the 1.1.2 > release didn't properly encode/decode in our system (on windows) > and I haven't had time to determine why. In any case, all of the features > jointly work

>> 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

Hi all, i use speex preprocessor features in this way: =================================== #define NN 160 /* 20msec di audio */ ... int tbc=0,c,d,ret; spx_int16_t TEMP_Buffer[NN]; char DLECODE; /* Inizializza il preprocessore Speex se non inizializzato */ if(Modem->speex_pp_state == NULL) { Modem->speex_pp_state = speex_preprocess_state_init(NN,AUDIO_SAMPLERATE); }