Questions tagged [speech]

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20
votes
4answers
28k views

Libraries for Voice Activity Detection (Not Speech Recognition)

As follow up to my previous question I was wondering if there are any speech detection libraries in existence. By speech detection I mean passing in an audio buffer and getting back an index of where ...
12
votes
2answers
13k views

When should I calculate PSD instead of plain FFT magnitude spectrum?

I have a thirty-second speech signal that was sampled at 44.1 kHz. Now, I would like to show what frequencies the speech has. However, I'm not sure what would be the best way to do that. It seems ...
9
votes
1answer
736 views

Detect human speech in realtime audio on mobile phones

I am looking to develop an Android app. As part of the functionality the app would require to randomly sample 3-5 seconds of audio and classify it as containing human speech or not. I understand that ...
8
votes
1answer
2k views

Detecting changes between voice and music

I have a bunch of audio files that have both speech and music parts (think radio). For instance, a given file might consist of the following sections: ...
8
votes
1answer
3k views

Speech Compression - In LPC how does the linear predictive filter work on a general level?

Hi I'm taking a multimedia systems course and I'm preparing for my exam on tuesday. I'm trying to get my head around LPC compression on a general level, but I'm having trouble with what is going on ...
8
votes
2answers
340 views

What input to use for an AR model of a vowel sound?

I've recorded a 2-sec pronunciation of a vowel sound. The first 0.12 or so seconds of the signal are shown below. Now, I've constructed an auto-regressive (AR) 8th-order model to compress this signal....
8
votes
3answers
12k views

FFmpeg audio filter pipeline for speech enhancement

Using ffmpeg, I'm recording a talk, its audio with a semi-distant microphone. It makes sense to somewhat enhance the speech clarity, reduce background static and ...
7
votes
4answers
3k views

How can I upsample 22 kHz speech audio recording to 44 kHz, maybe using AI?

I have a 22 kHz mono audio recording, which is mainly speech, a reading. I would like to upsample somehow to 44 kHz, to improve the audible quality. I have read about there are AI methods for ...
7
votes
1answer
1k views

how does this equation correspond to smoothing?

Please help me understand smoothing of data. This is a follow up to my previous question posted here. Especially the top answer by Junuxx where he says a way of smoothing a function $f(x)$ is: $$ f'[...
7
votes
3answers
1k views

What do colored noises look like in the time domain?

I understand that the time domain representation of white noise looks like impulses. How do colored noises like brown, pink etc. look like when we perform an inverse Fourier Transform on them ? What ...
7
votes
3answers
341 views

Why does the excitation signal appear, separated, at high quefrencies in the cepstrum?

So, I've just begun a speech and language processing course and have found the explanation of the process of getting the cepstrum of a signal and its properties a little confusing. The following is a ...
6
votes
2answers
3k views

Using DTW on the MFCC's to match a spoken word to a template

I am trying to code a simple algorithm in MATLAB that would be used to detect a single word. The goal would be to have a user record the word one time to act as a template, then make the user repeat ...
5
votes
3answers
3k views

VAD speech databases

Does anybody know any open voice/speech annotated database for Voice Activity Detection? Or any other corpus for speech evaluation purposes? The ones I know are private: AURORA, TIMIT, SpeechDat-Car, ...
5
votes
1answer
10k views

What are i-vectors and x-vectors in the context of Speech Recognition?

I have read that i-vectors and x-vectors are widely used in speaker recognition tasks but I don't get the difference between them and how exactly they work. Can someone explain it starting from the ...
5
votes
1answer
278 views

Detecting the original bandwidth of upsampled recordings

I have a set of recordings sampled at 16khz, but some of them are upsampled from 11khz and some from 8khz. Quite some of the recordings are noisy. What is the best way to classify the recordings ...
5
votes
1answer
4k views

Voice Audio Detection algorithm

I have to detect speech intervals in large pre-recorded files in my project. I think, there won't be so much noise in the background (audio will be recordered in the room or even in the studio), but ...
4
votes
2answers
3k views

Mel Cepstral Distortion

I am working on a speech synthesis model and I am looking to evaluate my synthesized speech. I found that most people use the Mel Cepstral Distortion (MCD) which can be calculated by the formula: $$\...
4
votes
1answer
535 views

What does MATLAB display when plotting a sound signal?

When you load the speech file 'mtlb' in MATLAB (which is by the way the voice of a woman saying the word 'MATLAB'), and plot the data, you get the following plot: My question is this: what does the ...
4
votes
1answer
1k views

Speech recognition: words vs. phonemes

One could train a speech recognizer with words or phonemes. I guess that they both have their pros and cons: with words there would be a lower error rate as phonemes can be put together building a ...
4
votes
2answers
458 views

Matching LPC frequency response to raw sample data frequency response

Background: The intention is feature/formant extraction from speech input. I have used an FFT on raw samples in the past and have done simple peak picking from a weighted average of frequencies over ...
3
votes
3answers
6k views

Speech Recognition - Project Idea

Wondering if someone could offer me any advice or help. Sorry if this question is too broad or anything. I'm wanting to complete an algorithm in basic Speech analysis. The algorithm will detect ...
3
votes
1answer
10k views

Calculating the total energy of a signal

I have a vector of signals and need to calculate the total energy. I have read somewhere that you can do this by summing up the entire vector and then finding the absolute value of the result. Is this ...
3
votes
3answers
2k views

Speech corpora for VAD

I'm doing a student research project connected with VAD. And I want to find speech corpora with added noise. I found many references to the NIST Speaker Recognition Corpora. But unfortunately, all ...
3
votes
1answer
1k views

Identifying the age of a speaker using speech recognition

I am just wondering if it's possible to gather the age group of someone speaking in a sample? For example, could I tell whether the sample is a child, teenage, adult, etc?
3
votes
3answers
3k views

How to simulation different kinds of Noises in speech signal?

What are the different kinds of noise in speech signal? How can I simulate the same in Matlab for adding to a clean speech signal?
3
votes
1answer
143 views

Convolution : Anechoic Speech signal and Impulse response

I am trying to perform convolution in MATLAB of an anechoic speech signal (2.1 s) and a impulse response (20 s) using the following code: ...
3
votes
2answers
1k views

Algorithm to detect if a spoken phrase matches a previously spoken phrase

I would like to create a very simple system that allows a user to train (once or multiple times) a spoken phrase (from 1 word to a whole sentence.) Then the (same) user would speak the phrase back, ...
3
votes
1answer
374 views

Real-time single speaker recognition

I'm developing an application for PC that records microphone data in real-time, and plays it back after applying some effects. I'd like to apply these effects only when a single known speaker is ...
3
votes
0answers
5k views

What's spectral "tilt"?

I am looking at article Speech-in-noise intelligibility improvement based on spectral shaping and dynamic range compression. In paragraph 2.2 the article mentions "tilt" of the spectral envelope. The ...
3
votes
0answers
470 views

Implementing blind deconvolution in MATLAB

I want to implement blind deconvolution for the signal $ r(n) = h(n) \star s(n) + a(n)$ in MATLAB where $r(n)$ is the recorded speech $h(n)$ is impulse response of room acoustics $s(n)$ is desired ...
3
votes
0answers
13k views

MFCC calculation

I've got a project and need to calculate MFCCs. I tried to read some tutorials and then make a MATLAB function but I seem to have wrong answers. I'd like to feed MFCCs to one of the classification ...
2
votes
3answers
308 views

Phase change rate of human speech

I have a .wav file of human speech, sampled at 48kHz, with useful signal up to 5kHz, and almost no noise. If I do Hilbert transform in MatLab, I get the Analytic signal: $$ s_\mathrm{a}[n] = s_\...
2
votes
1answer
1k views

Detect When Someone Has Stopped Talking

What's an extremely efficient way of detecting when a user has stopped talking into a microphone? When I use systems like Siri it can detect when I've stopped talking almost immediately, even when ...
2
votes
1answer
602 views

Speech Recognition Project - HMM

I am looking for advice on a project I am thinking about completing (for experience etc..) My project is triggering a set of traffic lights (simulation) using Speech recognition. In theory, I want to ...
2
votes
3answers
1k views

Understanding LPC for Formant Estimation

I went through the Matlab tutorial on Formant Estimation using LPC Coefficients. Though I vaguely understand the details, it's not entirely clear why we need to do this. From http://person2.sol.lu.se/...
2
votes
2answers
1k views

Why do envelope extraction before pitch detection?

I am referring to this report on pitch estimation. The author does envelope extraction using Hilbert transform before applying AMDF. What is the advantage of doing that? Is speech a narrowband or ...
2
votes
3answers
1k views

Estimation of Glottal Closure Instant

Glottal Closure Instants (GCIs) are referred to the instances of significant excitation of the vocal tract. I have seen in some papers that I can measure instant of glottal closure in a voiced segment ...
2
votes
1answer
229 views

Using 8 bit samples for speech comparison

I am making a speech comparison app in javascript. I found this dsp.SE post: Speech comparison algorithm for rating on similarities, where I read it is best to use mfcc and dtw algorithms. I ...
2
votes
1answer
2k views

Phone conversation diarization with LIUM

I am trying split call-center recording by speakers. LIUM seems to fit great. But results look random to me (green is etalon, gray is what I get): So I think I am doing something wrong. Maybe ...
2
votes
2answers
933 views

Emotional Tone detection using audio on mobile phones

Which audio features should be used to detect tone from audio? Are there any open source frameworks or implementations which can be ported to mobile phones to process audio? Alternatively, would it be ...
2
votes
2answers
219 views

Implementing a pitch shifter

I am trying to implement a pitch shifter similar to this one, in MATLAB for quick prototyping. My goal is to do the reverse, but I assume it is similar. The implementation details are missing. So I am ...
2
votes
1answer
466 views

audio quality evaluation

I am creating a dataset, where in many speakers are recording their speech signals using different microphones and in different environment. I would like to evaluate the quality of audio and discard ...
2
votes
2answers
322 views

Speech Overlap Detection

I’m trying to figure out how to go about differentiating between a single-voice speech and a multiple-voice conversation in which voices overlap. In other words – the moment of overlap is what I’m ...
2
votes
1answer
335 views

Speech segmentation for speaker recognition

I'm trying to implement a speaker recognition system and want to make sure I'm aware of the latest trends in speech segmentation. I've read a number of very different methods at a higher level but I'm ...
2
votes
2answers
65 views

How many bps would be required to reproduce the words in speech recognizably?

In Robert Gallager's lecture notes for 6.450 Principles of Digital Communications I, Exercise 2.1 asks an interesting conceptual question: Voice waveforms could be converted to binary data by ...
2
votes
1answer
78 views

How exactly does sound get encoded by a cochlear implant processor?

I've been wanting to know more about how sound is processed by a cochlear implant processor, how they are programmed, and how they stimulate the magnets and electrodes inside. How do you take pure ...
2
votes
0answers
128 views

Speaker diarization tool for acoustic analysis

I'm researching certain acoustic prosodic features during live clinical interactions. Because of the setting, the recordings always have cross channel bleed, and in some cases everything is recorded ...
2
votes
2answers
272 views

Speech signal formant spectrogram. How can we determine F1?

The formant spectrogram in this page points F1 and F2 as below; In bottom-right F1 movement, I thought F1 could be below blue one. But how can we determine F1 is upper one not below one? Is it ...
2
votes
0answers
1k views

Speex echo cancellation takes a long time (~20s) to converge

I have been experimenting with Speex's echo canceller during the past few days. I got the echo canceller to work, however, it takes a long time until it actually begins filtering out the echo. It ...
2
votes
0answers
111 views

What is actually transmitted following LPC of a speech frame?

For each frame, what's sent over to the receiver for decoding? The coefficients , pitch in some bits, voiced/unvoiced classification in another bit? Another broad question to develop intuition about ...