Questions tagged [mfcc]

Related to the calculation, verification, usage, and requirements for Mel Frequency Cepstral Coefficients.

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22
votes
2answers
11k views

How do I interpret the DCT step in the MFCC extraction process?

In most audio processing tasks, one of the most used transformations is MFCC (Mel-frequency cepstral coefficients). I mostly know the math that's behind the MFCC: I understand both the filterbank ...
18
votes
1answer
25k views

Help calculating / understanding the MFCCs: Mel-Frequency Cepstrum Coefficients

I've been reading bits and pieces online but I just can't piece it all together. I have some background knowledge of signals / DSP stuff which should be enough prerequisites for this. I'm interested ...
17
votes
4answers
30k views

Feature extraction for sound classification

I'm trying to extract features from a sound file and classify the sound as belonging to a particular category (eg : dog bark, vehicle engine e.t.c). I'd like some clarity on the following things : 1) ...
16
votes
1answer
11k views

Cepstral Mean Normalization

Can anyone please explain about Cepstral Mean Normalization, how the equivalence property of convolution affect this? Is it must to do CMN in MFCC Based Speaker Recognition? Why the property of ...
10
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3answers
9k views

Is this a correct interpretation of the DCT step in MFCC calculation?

This is a continuation of the discussion here. I would comment there, but I don't have 50 rep so I'm asking a new question. Here's how I understand the DCT step in the MFCC calculation process: The ...
8
votes
1answer
8k views

Speech comparison algorithm for rating on similarities

I am trying to compare 2 speech samples and rate them on similarities. Think of someone trying to repeat a phrase, and then comparing those 2 audio files. I started by implementing the MFCC (http://...
7
votes
1answer
3k views

MFCC feature extraction

I have a block of audio and I have performed an FFT on it. Now what I want to do is convert this FFT into a set of MFCCs, however while I know I need to do something with weighting the FFT samples ...
7
votes
1answer
5k views

What's the correct graphical interpretation of a series of MFCC vectors?

I'm studying speech-recognition, in particular the use of MFCC for feature extraction. All examples I've found online tend to graph a series of MFCC extracted from a particular utterance as follows (...
6
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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
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2answers
4k views

How to stitch together MFCCs from multiple frames?

I am trying to record a sound two times and compare the two recordings. I am playing exactly the same sound both times (for example, play a small .wav file twice and record it each time), so I hoped ...
5
votes
2answers
4k views

Gentle request for explanation on LPC and LPCC coefficients :)

If I understand what LPC does, I think. It predicts the next sample by taking into account previous $p$ samples. I don't understand why it is useful in DPS and speech recognition. I also came across ...
5
votes
0answers
761 views

Zero-padding of MFCC coefficients

I am trying to implement speech recognition using backpropagation algorithm, and I have been following this paper. I have followed it all the way, except that it tells me to zero-pad the coefficients ...
5
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2answers
740 views

Dynamic Time Warping - Comparing Values

Ok, so I'm trying to compare two different speech signals and I have come into a problem. Here goes: I have split the signal into blocks, and I have computed the MFCC coefficients of each block. I ...
4
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1answer
2k views

What is the purpose of the log when computing the MFCC?

The steps of computing the Mel-Frequency Cepstrum Coefficients (MFCC) are: ...
4
votes
1answer
945 views

Acoustic features distinguishing the male and female voice?

I would like to use MFCC analysis to distinguish between a male voice and a female voice. Are there any particular quantifiable characteristics consistent with, and exclusive to, either gender? (E.g....
4
votes
2answers
3k views

Sinusoidal liftering in implementations of MFCC

Some implementations of MFCC apply sinusoidal liftering as the final step in calculations of MFCC. It is claimed that speech recognition can be significantly improved. For instance, if $\text{MFCC}_i$ ...
4
votes
1answer
2k views

From MFCC to Machine learning. What are the steps?

I was able to get a dataset with MFCC coefficients. However, depending on the length of my sound file I get a different sized matrix. As in, 13 (13 MFCC coefficients) by XXX, where XXX will vary ...
4
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0answers
3k views

Verifying MFCC Final Result

I have created a Octave code for MFCC calculation for speech recognition, which takes a wav file as input and then gives the MFCC as the output. But the final results are a bit confusing, so I am ...
3
votes
1answer
4k views

Normalizing a vector with Mel Cepstrum Coefficients, Delta Coefficients and Log Energies for both

This is my very first signal processing exercise so I'm very new to this space. That being said the goal is to do isolate voice recognition in identifying someone saying yes and no.As the title ...
3
votes
1answer
828 views

If MFCC vectors are speaker independent, then how can we reconstruct unique speech signals from them?

Reconstructing a speech signal from a collection of MFCC vectors seems to work pretty well, but I've heard that one advantage of MFCCs is speaker-independence i.e. they are more-or-less the same ...
3
votes
2answers
3k views

Using MFCC in spoken words recognition

We're trying to implement a "simple" speech recognition application in MATLAB (isolated words from a very limited dictionary). We've been trying the following methods: Extract MFCC coefficients for ...
3
votes
1answer
8k views

MFCC - Significance of number of features

I have been doing some readings on the computation of Mel-Frequency Cepstral Coefficients (MFCC) and further use of Vector Quantizers (VQ) for recognition purposes. I am however stumped by the method ...
3
votes
2answers
6k views

what is the mel scale?

I am not sure I understand what the Mel Scale is. Googling doesn't give me various answers. I seem to be getting the same response again and again. Which would be something like: "The mel scale ...
3
votes
1answer
8k views

MFCC feature vector from wav file

I am trying to implement a spoken language identifier from audio files, using Neural Network. I need to generate one feature vector for each audio file. From what I have read the best features (for ...
3
votes
2answers
1k views

Vowel detection using MFCC

Does anybody know a simple way to recognize vowels from MFCCs? (not words, just phonemes: a,e,i,o,u). I heard this is a vastly known problem in DSP with several solutions like SVM, GMM and cosine ...
3
votes
2answers
971 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
3answers
3k views

Using MFCC to an ANN Speech Recognition System

I'm developing an Artificial Neural Network based Speech Recognition System using MFCCs. Suppose I have 260 input nodes in the ANN, and this number of nodes corresponds to the number of MFCCs that I ...
3
votes
0answers
11k 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 ...
3
votes
0answers
532 views

Questions about Bark scale filter bank implementation for bfcc's

I have a few questions regarding the implementation of Bark scale filter banks for the calculation of bark frequency cepstral coefficients. 1) Which filter shape is most commonly used and why? ...
3
votes
0answers
442 views

Finding similar fragment in recorded speech

I use MFCC algorithm for calculation of Mel-frequency coefficient for 2 files and DTW algorithm with Euclidean distance for finding similarity. I have results values around 400-600 on the files with ...
2
votes
1answer
1k views

MFCC process confusion

I have read through many papers related to the Mel-frequency cepstrum coefficient (MFCC): I have some confusion about the MFCC process: Many of the papers say that I have to do a FT (Fourier ...
2
votes
1answer
8k views

Mel filter in MFCC - is it necessary?

Is it necessary to use filter bank in MFCC process? Can anyone explain what is the Mel filter? I know that frequency in hertz is converted into Mel scale but is this formula can be directly applied ...
2
votes
2answers
1k views

Is it possible to apply a frequency filter a time domain signal?

Is it possible to frequency filter a time domain signal, without converting the signal to a frequency domain.. My question comes in regards how MFCC according to wiki and other pages describe the ...
2
votes
2answers
2k views

Difference Between MFCC of speech and speaker recognition

I am doing my project on speaker recognition. One of my friends is doing his project on speech recognition. Both of us need to calculate the MFCC for feature extraction. Is the MFCC going to be the ...
2
votes
1answer
593 views

Why are MFCCs of two equivalent signals completely different?

I have an audio file, of which I calculate 16 (actually 15 because I omit the first one) MFCCs in R. When I stream this file via VLC-Player and Icecast2-Server, receive it in Java (with the Player of ...
2
votes
2answers
3k views

How to apply a mel-filterbank to a signal?

I found this description. According to this, the next step is a "binning" where binning means that each FFT magnitude coefficient is multiplied by the corresponding filter gain and the results ...
2
votes
1answer
2k views

Onset Detection for Audio Signals

I am having a problem understanding how the author gets the onset envelope of an audio song in this paper. The entire section in question has been quoted below: First the input sound is resampled ...
2
votes
1answer
825 views

How to compare 2 matrices of MFCCs, keeping the time information

I have a corpus of several thousand sounds. Now I pick a sound sample S, and I want to find in my corpus the sound S' that is the most similar to S. The application is for music, for a composition ...
2
votes
1answer
1k views

MFCC delta: How to compute delta, in real time, with no future frames?

I am trying to compute Delta coefficients for real-time audio analysis. As far as I know, a valid formula is: $$d_t= \frac{\displaystyle\sum_{n=1}^{N}n\left(c_{t+n}-c_{t-n}\right)}{2\displaystyle\...
2
votes
1answer
2k views

Detecting phones in a word audio

I am working on speech recognition for Hindi language. My approach is to map speech to text based on phones. For this, first split the speech into the words and then map each word to text by detecting ...
2
votes
1answer
1k views

Training k-NN classifier with MFCC data

I am doing a personal project which aims to detect infant cry. I have an infant cry audio database and extracted the MFCC from these files using MATLAB. I've come up with 12 coefficients for each ...
2
votes
0answers
153 views

How to calculate MFCCs over a narrow frequency range?

I have a bunch of brief (~1 second each) wave files, some of which contain a frequency-modulated sound of interest between about 3900-4500 Hz. I thought I might run MFCC calculations on these sound ...
2
votes
1answer
815 views

Applying DTW on MFCC frames

I want to use MFCC (Mel-frequency cepstral coefficients) and DTW (dynamic time warping) algorithms to make a speech comparison script. I calculated MFCC and got 13 coefficients for each frame. How ...
2
votes
0answers
54 views

Supervised instrument recognition

Is it possible to use NMF for a sort of supervised polyphonic instrument recognition? I have training data for a timpani and training data for a bongo (or a bongo, snare and box drum). How can I ...
2
votes
0answers
253 views

MFCC help: Same sound, different coefficients?

Problem: I'm getting totally different MFCC coefficients for identical and near identical sounds like several finger snaps or several desk taps. What am I missing? I thought since the timbre doesn't ...
2
votes
0answers
281 views

Most efficient algorithm for comparing two paths

I'm working with a Continuous Hidden Markov Model, and using the Viterbi Decoder which finds the best possible path for a given sequence. Here is how my algorithm works: ...
1
vote
1answer
316 views

Applying a Liftering function to an audio signal

Is it necessary to perform the liftering function before applying MFCC to an audio signal?
1
vote
1answer
14k views

What is the advantage of applying a Hamming window for MFCC calculations?

I am trying to implement MFCC by following this and I found that there is a step in which signals are divided into frames and then passed on to Hamming windowing process. The reason given there is to ...
1
vote
1answer
732 views

Two voice pronunciation comparison similarity MFCC + DTW

Calculate each MFCC to compare wave file A and wave file B, and then use FastDTW to measure the distance after two sets of MFCCs. We compared the four wave files and obtained the Euclidean distance ...
1
vote
2answers
698 views

Why discrete cosine transform may not maintain locality

In paper Convolutional neural network for speech recognition, they say I didn't understand the highlighted sentence.