Convert a power-spectrogram to decibel units in TensorFlow

power_to_db.py

def power_to_db(S, amin=1e-16, top_db=80.0):
    """Convert a power-spectrogram (magnitude squared) to decibel (dB) units.

    Computes the scaling ``10 * log10(S / max(S))`` in a numerically
    stable way.

    Based on:
    https://librosa.github.io/librosa/generated/librosa.core.power_to_db.html
    """
    def _tf_log10(x):
        numerator = tf.math.log(x)
        denominator = tf.math.log(tf.constant(10, dtype=numerator.dtype))
        return numerator / denominator
    
    # Scale magnitude relative to maximum value in S. Zeros in the output 
    # correspond to positions where S == ref.
    ref = tf.reduce_max(S)

    log_spec = 10.0 * _tf_log10(tf.maximum(amin, S))
    log_spec -= 10.0 * _tf_log10(tf.maximum(amin, ref))

    log_spec = tf.maximum(log_spec, tf.reduce_max(log_spec) - top_db)

    return log_spec