Code solving

clc
disp(' ');
disp(' ');
[s1 fs1] = wavread('b');
[g fs2] = wavread('l');

t = 0:1/fs1:(length(s1) - 1)/fs1;
plot(t, s1), axis([0, (length(s1) - 1)/fs1 -0.4 0.5]);
title('Plot of signal s1.wav');
xlabel('Time [s]');
ylabel('Amplitude (normalized)')

pause
close all

M = 100;
N = 256;
frames = blockFrames(s1, fs1, M, N);
t = N / 2;
tm = length(s1) / fs1;
subplot(121);
imagesc([0 tm], [0 fs1/2], abs(frames(1:t, :)).^2), axis xy;
title('Power Spectrum (M = 100, N = 256)');
xlabel('Time [s]');
ylabel('Frequency [Hz]');
colorbar;

What is M,N....?

wat does blockframes symbolises?