mltu/transformer.py SpectrogramPadding Bag.

[tosa-no-onchan]

Hi @pythonlessons,
I think, Class SpectrogramPadding has a bag.

Original code:
A short spectrogram data is slide to backward(tail) of padded_spectrogram.
But, I want, A short spectrogram data will be slide to forward(head) of padded_spectrogram.

class SpectrogramPadding(Transformer):
    """Pad spectrogram to max_spectrogram_length
    
    Attributes:
        max_spectrogram_length (int): Maximum length of spectrogram
        padding_value (int): Value to pad
    """
    def __init__(
        self, 
        max_spectrogram_length: int, 
        padding_value: int
        ) -> None:
        self.max_spectrogram_length = max_spectrogram_length
        self.padding_value = padding_value

    def __call__(self, spectrogram: np.ndarray, label: np.ndarray):
        padded_spectrogram = np.pad(spectrogram, ((self.max_spectrogram_length - spectrogram.shape[0], 0),(0,0)), mode="constant", constant_values=self.padding_value)

        return padded_spectrogram, label

New code:

class SpectrogramPadding(Transformer):
    """Pad spectrogram to max_spectrogram_length
    
    Attributes:
        max_spectrogram_length (int): Maximum length of spectrogram
        padding_value (int): Value to pad
    """
    def __init__(
        self, 
        max_spectrogram_length: int, 
        padding_value: int,
        append: bool = True
        ) -> None:
        self.max_spectrogram_length = max_spectrogram_length
        self.padding_value = padding_value
        self.append=append

    def __call__(self, spectrogram: np.ndarray, label: np.ndarray):
        #print('spectrogram.shape:',spectrogram.shape)
        # spectrogram.shape: (1032, 193)
        if self.append==False:
            padded_spectrogram = np.pad(spectrogram, 
                ((self.max_spectrogram_length - spectrogram.shape[0], 0),(0,0)),mode="constant",constant_values=self.padding_value)
        else:
            l,h =spectrogram.shape
            lng = self.max_spectrogram_length - l
            if lng > 0:
                a = np.full((lng,h),self.padding_value)
                padded_spectrogram = np.append(spectrogram, a, axis=0)
            else:
                padded_spectrogram = spectrogram
        return padded_spectrogram, label

[pythonlessons]

Hey, thanks. The idea was that it would append the end of the spectrogram by default, not sure how I missed this, but definitely I will fix this in the next release. Thanks!

Your code is a little complicated. Right now it is following:

padded_spectrogram = np.pad(spectrogram, ((self.max_spectrogram_length - spectrogram.shape[0], 0),(0,0)), mode="constant", constant_values=self.padding_value)

To pad the end of it is as simple as this:

padded_spectrogram = np.pad(spectrogram, ((0, self.max_spectrogram_length - spectrogram.shape[0]),(0,0)), mode="constant", constant_values=self.padding_value)

[pythonlessons]

Issued fixed