similar to: voice activity detection

Tom Harper wrote: > Steve, > > The main problem I am having with the system is clipping off the start > of someone's speech when they first start talking- the ends of the > sentences > seem to be handled properly. I am wondering whether this is the fault > of the > audio playback system or whether this is a speex issue- I don't seem to get that; I suppose

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,

On Mar 28, 2004, at 8:23 PM, Jean-Marc Valin wrote: >> The st->zeta pointer isn't freed in the >> speex_preprocess_state_destroy() >> function of the preprocess.c file (alloced in line 167). It's in >> Speex 1.1.4 >> by the way. > > Oops... Thanks for letting me know. I'll change that for the next > release (in the mean time, the fix is

Jean-Marc Valin wrote: >>Reverberation suppression? >> >> > >Basically, it means that if you are in a room with lots of echo (long >decay), I can reduce it a bit. > > > >>I guess this would help reduce local source echoes? I've never >>_noticed_ that to be a problem in my use, but I would imagine that >>using a notebook's

Tom Harper wrote: > Hi All & Jean Marc, > > Once again I find myself delving into the pre-processing code to fiddle > with the VAD, AGC and denoising code. > > Where i am at is that I have implemented all of Steve Kann's mods, and > they are 90% of the way there in terms of working, except that I am still > having issues denoising open air mics. But that is

From 1.2rc1 source code: preprocess.c: /* FIXME: This VAD is a kludge */ st->speech_prob = Pframe; if (st->vad_enabled) { if (st->speech_prob > st->speech_prob_start || (st->was_speech && st->speech_prob > st->speech_prob_continue)) { st->was_speech=1; return 1; } else { st->was_speech=0; return 0; } } else { return 1; } AND case

> 1) AGC: This seems to work pretty well in all cases. I had previously > hacked-in the "compander" filter from sox for a similar effect. What > I've noticed is that speex_preprocess's AGC has no "knobs", and it > seems to use an attack/decay that is a lot faster than what I had > chosen from the sox compander, but it works pretty well nonetheless.

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

> 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

Echo cancellation works like a charm, but it seems to confuse the preprocessor a bit. If listening to background music (properly fed through the echo cancellator), the music is removed but the result is still detected as speech even if almost silence remains in the signal. Also, the AGC keeps adjusting to the minute remains in the signal, meaning that sooner or later it will amplify the

Hello, I am wondering whether Speex's voice activity detection mechanism can be used independently of encoding and decoding speech, and how reliable it is in general. I need this kind of functionality for a project I am working on, and I was wondering if Speex provides it in a ready-to-use fashion, or if it requires modification of the source code. If so, I would be glad to consider doing

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 wrote: >> 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

I have been trying to understand how to get the VAD algorithm working. I sent an input stream of all zeros into the preprocessor but still got a return value of 1 indicating that speech was detected. Is this feature not available with the latest release? I thought at the very least it would detect this as silence and return 0 but that does not seem to be the case. Does anyone have any

Hi The latest SVN trunk for speex has changed the SpeexPreprocessState to an opaque structure, for jolly good software engineering reasons. However, the Analogue AGC (AAGC) feature of iaxclient (in audio_enode.c) relies on some members of this. It uses speech_prob to detect when there is enough speech to consider AAGC and then loudness2 to decide how to adjust the input mixer. We want to use

Hey sorry to hijack this thread, but I just remembered a request I wanted to make to the speex devs. I tried using the activity detector, but I just couldn't get it working well. I ended up using my own, where I think it just considered voice on if it passed a certain threshold (I know, pretty primitive). I also tried one that checked for a signal, like if the strongest frequency

Hi, Here are the next two patches for the data export. speex_get_psd should be applied after speex_get_agc_gain (sent in previous mail). It allows applications to get the power spectrum for the signal and the noise estimate. speex_get_prob should be applied last. It allows fetching the speech probability of the current frame (the value that the _PROB_START and _PROB_CONTINUE parameters are

> 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

This must be a simple issue, but I cannot figure it out. I want to use VAD, but I don't know how to check if the actual frame has voice in it or not. So, in my code, I do: int tmp = 1; speex_preprocess_ctl(preprocess_state, SPEEX_PREPROCESS_SET_VAD, &tmp); speex_preprocess_ctl(preprocess_state, SPEEX_PREPROCESS_SET_DENOISE, &tmp); then later, for each frame

Thanks for your reply. I changed my code to: if (speex_preprocess_run(preprocess_state, shortPointer) == 1) { speex_encode_int(enc_state, shortPointer, &enc_bits); } In the mobile version of the software, compiled against the mobile build of Speech, I get 1 and 0 based on whether the speech is detected. In the version of the software compiled against the Win32 version of Speex,