what should be the constraint on window length in function melspectrogram?

hi there

I am using the in built function melspectrogram in a loop, for calculation of spectrograms of a wav dataset.

The code I am using is given below:

    fs = 44100;
    frameDuration = 0.046;
    hopDuration = 0.023;
    numBands = 128;
    frameLength = round(frameDuration*fs);
    hopLength = round(hopDuration*fs);
    
    spec = melSpectrogram(x,fs, ...
        'WindowLength',frameLength, ...
        'OverlapLength',frameLength - hopLength, ...
        'FFTLength',2048, ...
        'NumBands',numBands, ...
        'FrequencyRange',[50,8000]);
    
    

getting the error below:

    Error using audio.internal.MelSpectrogramValidator/validateOptionalInputs (line 97)
    Invalid window length. WINDOWLENGTH must be in the range [2,size(x,1)], where x is the audio input.
    The default window length depends on the specified sample rate: round(fs*0.03).
    

the audio data length is 160000. Can someone guide me whats wrong here? This is working fine on other dataset, with sampling rate=16000.

Thanks

Answer 1

[jibrahim]

Hi Krishna,

This looks fine. Make sure that your input x is a column vector, not a row vector. The function treats each column as a separate channel, so I would expect to see this error if x is a long row vector,

[krishna Chauhan]

No sir x is coloumn vector, I am applying same process to both the datsets.

[jibrahim]

OK... Could you update your reproduction steps to include x? You can either instantiate a vector of the same dimensions, or attach x in a MAT file.

[krishna Chauhan]

Yes sir you are right. In first case read(ads) thowring x as 60000X1 double, while in scond the size is 1X6000 double I just checked.Now I can make x as x', but my proble is why read(ads) is reading wav files in different way.

Thanks