How can I extract the data points (corresponding y value for x values) from a waveplot

Solution 1:

librosa.display.waveplot compute and plots the amplitude envelope of the audio signal. You can see how this is done by looking at the source code of the function (accessible via "view source" on the documentation page for the function).

Here is the relevant part of the code for computing the envelope.

def __envelope(x, hop):
    """Compute the max-envelope of non-overlapping frames of x at length hop

    x is assumed to be multi-channel, of shape (n_channels, n_samples).
    """
    import numpy as np

    x_frame = np.abs(librosa.util.frame(x, frame_length=hop, hop_length=hop))
    return x_frame.max(axis=1)

# Reduce by envelope calculation
env = __envelope(y, hop_length)

Where hop_length is the number of audio samples per point of the envelope.