sort_beats.py

import sys
import echonest.audio as audio

def main(filename):
    inputFile = audio.LocalAudioFile(filename)
    inputChunks = inputFile.analysis.beats

    modifiedAudio = audio.getpieces(inputFile, sorted(inputChunks, compare))
    modifiedAudio.encode('sorted.mp3')

def compare(a, b):
    return cmp(a.duration, b.duration)

main(sys.argv[1])