import ffmpeg

in_file = ffmpeg.input(path)

import time
t0 = time.time()
(
    ffmpeg
    .concat(*[
        in_file
        .filter_('atrim', start=start, end=end)
        for kind, start, end in segmentation
        if kind == 'music' and end - start > 30
    ], v=0, a=1)
    .output(path.replace('mp4', 'mp3'))
    .run()
)
t1 = time.time()
print(f"audio written in {t1 - t0} seconds")