audio feature extraction wav files inside a folder

I've seen that some questions have been answered to similar questions to mine. They're similar but different enough to not answer my question.

I'm trying to extract several audio features from .wav files located inside a folder.

I need the below code to have a for loop that goes through each .wav file in that folder, extracts all required features for that file, saves the features somewhere (.mat file or excel - not too bothered but actually maybe excel would be easier in this case) and then does this for every .wav file until there are no files left inside that folder.

My code is not built for that and I've been googling and experimenting and can't figure out how to come up with a solution.

Could you please help me?

(I've got audio toolbox installed and my Matlab version is R2023a if it's useful for you at all to know that).

% select the folder path where audio files are located
folderPath = 'C:\Users\Documents\MATLAB\audioExperiment3';


fileList = dir(fullfile(folderPath,'*.wav')); % Change the file extension if needed

ads = audioDatastore(folderPath);


for i = 1:length(fileList)
        % Read the audio file
    filePath = fullfile(folderPath,fileList(i).name);
    [audioIn,fs] = audioread(filePath);

% obj. % adds mfcc to the list of enabled features.
% obj.
% obj.melSpectrum = true
% obj.barkSpectrum = true
% obj.erbSpectrum = true
% obj.mfccDelta = true
% obj.mfccDeltaDelta = true
% obj.gtcc = true
% obj.gtccDelta = true
% obj.gtccDeltaDelta = true
% obj.spectralCrest = true
% obj.spectralDecrease = true
% obj.spectralEntropy = true
% obj.spectralFlatness = true
% obj.spectralFlux = true
% obj.spectralRolloffPoint = true
% obj.spectralSkewness = true
% obj.spectralSlope = true
% obj.spectralSpread = true
% obj.
% obj.zerocrossrate = true
% obj.shortTimeEnergy = true

    aFE = audioFeatureExtractor("SampleRate",fs, ...
    "SpectralDescriptorInput",...
    "barkSpectrum", ...
    "spectralCentroid", ...
    "spectralKurtosis",...
    "pitch",...
    "linearSpectrum",...
    "mfcc",...
    "harmonicRatio");

     
    saveFilePath = fullfile(folderPath,[fileList(i).name '_features.mat']);
    save(saveFilePath,'aFE');
end

Also Matlab is showing me this error:

>> AudioFeaturesExtractAudioToolbox_04

Error using set.mfcc

Expected mfcc to be one of these types:

logical, double, single, uint8, uint16, uint32, uint64,

int8, int16, int32, int64

Instead its type was string.

Error in audioFeatureExtractor/set.mfcc (line 1694)

validateattributes(val,{'logical','numeric'}, ...

Error in audioFeatureExtractor (line 444)

set(obj,parsedStruct)

Error in AudioFeaturesExtractAudioToolbox_04 (line 41)

aFE = audioFeatureExtractor("SampleRate",fs, ...

>>

______________________

Thanks in advance for any help if possible.

Answer 1

[Walter Roberson]

    aFE = audioFeatureExtractor("SampleRate",fs, ...
    "SpectralDescriptorInput",...
    "barkSpectrum", ...
    "spectralCentroid", ...
    "spectralKurtosis",...

You are missing a value for spectralCentroid, so it is trying to understand the value of spectralCentroid as being the string object "spectralKurtosis"