import audiomp3, audiocore

import ulab.numpy as np

TEST_FILE = (

__file__.rsplit("/", 1)[0]

+ "/../circuitpython-manual/audiocore/jeplayer-splash-44100-stereo.mp3"

)

def normalized_rms_ulab(values):

values = np.frombuffer(values, dtype=np.int16)

# this function works with ndarrays only

minbuf = np.mean(values)

values = values - minbuf

samples_sum = np.sum(values * values)

return (samples_sum / len(values)) ** 0.5

def print_frame_loudness(decoder, n):

for i in range(n):

result, buf = audiocore.get_buffer(decoder)

print(f"{i} {result} {normalized_rms_ulab(buf):5.0f}")

print()

# First frames

decoder = audiomp3.MP3Decoder(TEST_FILE)

print_frame_loudness(decoder, 8)

# First frames (fresh decoder)

decoder = audiomp3.MP3Decoder(TEST_FILE)

print_frame_loudness(decoder, 2)

# First frames (reopen)

decoder.open(TEST_FILE)

print_frame_loudness(decoder, 3)