I have recorded a rgb video and extract g frames vector and calculate it's mean now I want to calculate beats per minute kindly help how can I calculate BPM

vid= VideoReader('output.avi');

numFrames = vid.NumberOfFrames;

n=numFrames;

for x = 1:n

vidFrame = read(vid,x);

G = vidFrame(330:680, 500:780,2);

g(x)=mean2(G);

end

Answer 1

[Bjorn Gustavsson]

In order to estimate frequencies you have to look at the time-variation of your signal, depending on the variability of this you might get away with a single Fourier-transform of your time-series, but if your signal has a varying frequency (heart-rate of a resting person that then starts running, or a melody being played on a piano for example) you might be better off looking at its stft using the spectrogram function. My advice is to have a look at the help and documentaion to spectrogram.

HTH