Super simple BPM detection with pydub

bpm_detection.py

from pydub import AudioSegment
from pydub.silence import detect_nonsilent

seg = AudioSegment.from_file("./ghosts_and_stuff.m4a")

# reduce loudness of sounds over 120Hz (focus on bass drum, etc)
seg = seg.low_pass_filter(120.0)

# we'll call a beat: anything above average loudness
beat_loudness = seg.dBFS 

# the fastest tempo we'll allow is 240 bpm (60000ms / 240beats)
minimum_silence = int(60000 / 240.0)

nonsilent_times = detect_nonsilent(seg, minimum_silence, beat_loudness)

spaces_between_beats = []
last_t = nonsilent_times[0][0]

for peak_start, _ in nonsilent_times[1:]:
    spaces_between_beats.append(peak_start - last_t)
    last_t = peak_start

# We'll base our guess on the median space between beats
spaces_between_beats = sorted(spaces_between_beats)
space = spaces_between_beats[len(spaces_between_beats) / 2]

bpm = 60000 / space