how to run function with struct

% How do I ran this function using struct other function midFeaures are included in matlab
% I cannot run the struct


function [midFeatures, Centers, stFeaturesPerSegment] = ...
    featureExtractionFile(signal, stWin, stStep, mtWin, mtStep, featureStatistics)

% function [midFeatures, Centers, stFeaturesPerSegment] = ...
%    featureExtractionFile(fileName, stWin, stStep, mtWin, mtStep, ...
%    featureStatistics)
%
% [mtFeatures, centers] = featureExtractionFile(fileName,  ...
%    0.040, 0.040, 2.0, 1.0, {'mean','std'});
%
% This function reads a struct element and computes 
% audio feature statitstics on a mid-term basis.
%
% ARGUMENTS:
% - signal:             audio signal (struct)
% - stWin:              short-term window size (in seconds)
% - stStep:             short-term window step (in seconds)
% - mtWin:              mid-term window size (in seconds)
% - mtStep:             mid-term window step (in seconds)
% - featureStatistics:  list of statistics to be computed (cell array)
%
% RETURNS
% - midFeatures         [numOfFeatures x numOfMidTermWins] matrix 
%                       (each collumn represents a mid-term feature vector)
% - Centers:            representive centers for each 
%                       mid-term window (in seconds)
% - stFeaturesPerSegment cell that contains short-term feature sequences
%
% (c) 2014 T. Giannakopoulos, A. Pikrakis

% convert mt win and step to ratio (compared to the short-term):
mtWinRatio  = round(mtWin  / stStep);
mtStepRatio = round(mtStep / stStep);

readBlockSize = 60; % one minute block size:

% get the length of the audio signal to be analyzed:
% ndret til struct brug!
a = signal.Filt_data;
fs = signal.SampleRate;

numOfSamples = length(a);
BLOCK_SIZE = round(readBlockSize * fs); % Antal samples per minut
curSample = 1;
count = 0;
midFeatures = [];
Centers = [];
stFeaturesPerSegment = {};

while (curSample <= numOfSamples) % while the end of file has not been reahed
    % find limits of current block:
    N1 = curSample;
    N2 = curSample + BLOCK_SIZE - 1;
    if (N2>numOfSamples)
        N2 = numOfSamples;
    end
    
    tempX = signal.Filt_data(N1:N2,:);    % ndret til struct brug!

    % STEP 1: short-term feature extraction:
    Features = stFeatureExtraction(tempX, fs, stWin, stStep);
       
    % STEP 2: mid-term feature extraction:
    [mtFeatures, st] = mtFeatureExtraction(...
        Features, mtWinRatio, mtStepRatio, featureStatistics);
    
    for (i=1:length(st)) 
        stFeaturesPerSegment{end+1} = st{i}; 
    end
    Centers = [Centers readBlockSize * count + (0:mtStep:(N2-N1)/fs)];
    midFeatures = [midFeatures mtFeatures];
    
    % update counter:
    curSample = curSample + BLOCK_SIZE;
    count = count + 1;    
end
if (length(Centers)==1)
    Centers = (numOfSamples / fs) / 2;
else
    C1 = Centers(1:end-1);
    C2 = Centers(2:end);
    Centers = (C1+C2) / 2;
end

if (size(midFeatures,2)>length(Centers))
    midFeatures = midFeatures(:, 1:length(Centers));
end

if (size(midFeatures,2)<length(Centers))
    Centers = Centers(:, 1:size(midFeatures,2));
end

Answer 1

[Walter Roberson]

The code expects the first parameter to be a struct with fields Filt_Data and SampleRate . Filt_Data is expected to be a 2D array with one column per channel.

[Kamil Kacer]

Can you provide an example please i not sure how to format it thank you

[Walter Roberson]

[data,Fs] = audioread('RockGuitar-16-44p1-stereo-72secs.wav');
signal = struct('Filt_Data', data, 'SampleRate', Fs);

[midFeatures, Centers, stFeaturesPerSegment] = ...
  featureExtractionFile(signal, 0.040, 0.040, 2.0, 1.0, {'mean','std'});

[Kamil Kacer]

% Subsequently i want to plot it
% Using 
featureExtractionFile(signal, 0.05, 0.025, 2, 1, {'mean', 'median', 'std', 'stdbymean', 'max', 'min'});
plotFeaturesFile('audio.wav', 6)
% But it doesnt work... Any sugestion please 


function plotFeaturesFile(wavFileName, featureToPlot)

%
% function plotFeaturesFile(wavFileName, featureToPlot)
%
% This function is used to plot feature sequences and 
% respective mid-term statistics
% 
% Example:
% plotFeaturesFile('diarizationExample.wav',6)

% feature extraction parameters (windows and statistics):
shortTermSize = 0.050; shortTermStep = 0.025;
midTermSize = 2.0; midTermStep = 1.0;
Statistics = {'mean','median','std','stdbymean','max','min'};
% feature extraction (mid-term and short-term):
[midFeatures, Centers, stFeaturesPerSegment] = featureExtractionFile(...
    wavFileName, shortTermSize, shortTermStep, midTermSize, midTermStep, Statistics);
numOfShortFeatures = size(stFeaturesPerSegment{1}, 1); 
% Plot results:
figure; hold on; Colors = {'r', 'g', 'k', 'm', 'y','c'};
% Plot mid-term feature statistics:
for s=1:length(Statistics) % for each statistic:
    P = plot(Centers, ...
        midFeatures(featureToPlot + numOfShortFeatures * (s-1), :), Colors{s});
    set(P, 'linewidth', 2);
end
% Plot short-term feature sequence:
for i=1:length(stFeaturesPerSegment) % for each mid-term window:
    % get current short-term feature sequence to be plotted:
    curSFeature = stFeaturesPerSegment{i}(featureToPlot, :);    
    % create time array:
    stTime = (i-1) * midTermStep : shortTermStep : ...
        (i-1) * midTermStep + (length(curSFeature)-1)*shortTermStep;
    % plot the respective short-term feature sequence:        
    plot(stTime, curSFeature);
end
legend([Statistics, 'short-term sequence']);
xlabel('Time (seconds)'); ylabel('Feature Values');
title(['Feature ' num2str(featureToPlot)]);

[Walter Roberson]

featureExtractionFile was originally literally a function to extract features from a file.

Someone along the way changed the code to expect a structure of information, and to not accept a file, but did not change the name of the function.

So your code

featureExtractionFile(signal, 0.05, 0.025, 2, 1, {'mean', 'median', 'std', 'stdbymean', 'max', 'min'});

is extracting features from the signal struct, and is throwing away the extracted features (you do not assign to output).

Then your code

plotFeaturesFile('audio.wav', 6)

passes a file name into a function that sets up, and does

[midFeatures, Centers, stFeaturesPerSegment] = featureExtractionFile(...
    wavFileName, shortTermSize, shortTermStep, midTermSize, midTermStep, Statistics);

but that is going to fail because featureExtractionFile now has no ability to extract information from files, and instead needs to extract from a structure.

However when I look at the code, it looks to me as if you could probably do

plotFeaturesFile(signal, 6)

as the code does not validate that it has been passed a file, so you can pass it a struct to pass to featureExtractionFile

It is a mystery to me as to why someone would modify the featureExtractionFile code to require a struct instead of a file without renaming the function. It would have made a lot more sense to have created a new featureExtractionStruct (that does what the current one does with struct input), and to have made featureExtractionFile into a routine that accepted a file name and read the audio data from it and created the struct and called featureExtractionStruct .

[Kamil Kacer]

Maaaaaan It worked thats like 1000$ worth advice

Thank you so much from SVK