formant values from lpc analysis"

Hi, I want to get formants from an audio file, I use LPC analysis file from there, But the code gives only 1 formant value, (1 value for f1, 1 value for f2, 1 value for f3, etc.)

But another audio software gives more than 1 value for each one, I think matlab's output for formant analysis gives an average value for whole audio file, Is it logic? Also, is it logical that sampling audio file therefore getting more than one formant value? Regards.