Python script to cut out silent parts from a video. Uses moviepy.

cut_silence.py

#!/usr/bin/env python
#
# Based on a script by Donald Feury
# https://gitlab.com/dak425/scripts/-/blob/master/trim_silenceV2
# https://youtu.be/ak52RXKfDw8

import math
import sys
import subprocess
import os
import shutil
from moviepy.editor import AudioClip, VideoFileClip, concatenate_videoclips


# Iterate over audio to find the non-silent parts. Outputs a list of
# (speaking_start, speaking_end) intervals.
# Args:
#  window_size: (in seconds) hunt for silence in windows of this size
#  volume_threshold: volume below this threshold is considered to be silence
#  ease_in: (in seconds) add this much silence around speaking intervals
def find_speaking(audio_clip, window_size=0.1, volume_threshold=0.01, ease_in=0.25):
    # First, iterate over audio to find all silent windows.
    num_windows = math.floor(audio_clip.end/window_size)
    window_is_silent = []
    for i in range(num_windows):
        s = audio_clip.subclip(i * window_size, (i + 1) * window_size)
        v = s.max_volume()
        window_is_silent.append(v < volume_threshold)

    # Find speaking intervals.
    speaking_start = 0
    speaking_end = 0
    speaking_intervals = []
    for i in range(1, len(window_is_silent)):
        e1 = window_is_silent[i - 1]
        e2 = window_is_silent[i]
        # silence -> speaking
        if e1 and not e2:
            speaking_start = i * window_size
        # speaking -> silence, now have a speaking interval
        if not e1 and e2:
            speaking_end = i * window_size
            new_speaking_interval = [speaking_start - ease_in, speaking_end + ease_in]
            # With tiny windows, this can sometimes overlap the previous window, so merge.
            need_to_merge = len(speaking_intervals) > 0 and speaking_intervals[-1][1] > new_speaking_interval[0]
            if need_to_merge:
                merged_interval = [speaking_intervals[-1][0], new_speaking_interval[1]]
                speaking_intervals[-1] = merged_interval
            else:
                speaking_intervals.append(new_speaking_interval)

    return speaking_intervals


def main():
    # Parse args
    # Input file path
    file_in = sys.argv[1]
    # Output file path
    file_out = sys.argv[2]

    vid = VideoFileClip(file_in)
    intervals_to_keep = find_speaking(vid.audio)

    print("Keeping intervals: " + str(intervals_to_keep))
    
    keep_clips = [vid.subclip(start, end) for [start, end] in intervals_to_keep]

    edited_video = concatenate_videoclips(keep_clips)
    edited_video.write_videofile(file_out,
        fps=60,
        preset='ultrafast',
        codec='libx264',
        temp_audiofile='temp-audio.m4a',
        remove_temp=True,
        audio_codec="aac",
        threads=6
    )

    vid.close()

if __name__ == '__main__':
    main()