[Compiler] la fonction LPC (linear predectif coding)

Bonsoir a tous
j'ai un petit probléme avec la fct LPC car je ne trouve pas assez document qui me fait comprendre bien se que sait
j'aimerai bien que je trouve de l'aide
1- c'est quoi LPC et quelle est son role
2-comment choisir ce qui est en rouge
3-quelle est le role de se qui est en bleu
merci bcp

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function lpc_training
% This code is for creating the library of Linear Predictive Coding (LPC) features.

Fs = 10000;   % Sampling Frequency (Hz)
n = 20;       % LPC order
Nseconds = 1; % Length of speech signal

% List of words (you can add more words to this list but make sure
% each word has five characters (if less then pad it with spaces)
words = ['   up';
         ' down';
         ' left';
         'right'];

% Matrix to store features for each word (rows correspond to words)
fw = zeros(size(words,1),n);

fprintf('You will get one second to say each word.\n\n');

% For each word, get the word from microphone and compute its features
for i=1:size(words,1)
    fprintf('Hit enter and say immediately ''%s'':',words(i,:));
    % pause for enter key
    junk=input('');
    
    % get a word from microphone
    y  = wavrecord(Nseconds*Fs, Fs, 'double');

    % Calculate the features of the word
    f = lpc_feature(y,n);
    
    % Save them in the features matrix
    fw(i,:) = f;
    %     abs(f)
    %     plot(1:Fs,fft(y));
end

% Save features matrix to a file (this file will be loaded into Matlab during speech recognition)
save words_lpc.mat Fs n words fw;