README.md

yt-album-combiner

This script is intended to take video a YouTube video and audio from another YouTube video and combine them into a new video.

Dependencies

apt install ffmpeg youtube-dl

download.py

#!/usr/bin/env python3
"""
This takes a youtube video and replaces the audio with an album's audio
"""

__author__ = "Dana Merrick"
__version__ = "0.1.0"
__license__ = "MIT"

#TODO: use ffmpeg's minterpolate filter to smooth output

#TODO: use youtube-dl like this
# from __future__ import unicode_literals
# import youtube_dl
# ydl_opts = {}
# with youtube_dl.YoutubeDL(ydl_opts) as ydl:
# 	ydl.download(['https://www.youtube.com/watch?v=BaW_jenozKc'])

import os
import subprocess

video_id = "yDiD8F9ItX0"
audio_id = "MHf7TimSfrM"

def main():
    download_files()
    convert_to_mp4()
    match_lengths()
    combine_files()
    cleanup()

def download_files():
    video_url = f"https://www.youtube.com/watch?v={video_id}"
    audio_url = f"https://www.youtube.com/watch?v={audio_id}"
    cmd = f"youtube-dl -k --id -f bestvideo+bestaudio --merge-output-format mkv {video_url}"
    print(cmd)
    os.system(cmd)
    cmd = f"youtube-dl -k --id --extract-audio --audio-format flac --audio-quality 0 {audio_url}"
    print(cmd)
    os.system(cmd)

def match_lengths():
    video_length = video_frame_count()
    audio_length = audio_frame_count()
    multiplier = audio_length / video_length
    warp_video(multiplier)

#TODO: this seems dumb, the only reason I'm doing it is 
# because video_frame_count only seems to work with mp4
def convert_to_mp4():
    # convert it to mp4, remove audio
    cmd = f"ffmpeg -i {video_id}.mkv -c copy -an {video_id}.mp4"
    print(cmd)
    os.system(cmd)

# get length of video
def video_frame_count():
    cmd = f"ffprobe -show_entries stream=duration -of compact -v 0 {video_id}.mp4"
    print(cmd)
    result = subprocess.run(cmd.split(" "), stdout=subprocess.PIPE)
    print(result.stdout)
    frames = result.stdout.decode("utf-8").split('=')[-1]
    return float(frames)

# get length of audio
def audio_frame_count():
    cmd = f"ffprobe -show_entries stream=duration -of compact -v 0 {audio_id}.flac"
    print(cmd)
    result = subprocess.run(cmd.split(" "), stdout=subprocess.PIPE)
    print(result.stdout)
    frames = result.stdout.decode("utf-8").split('=')[-1]
    return float(frames)

def warp_video(multiplier):
    cmd = f"ffmpeg -i {video_id}.mp4 -filter:v 'setpts={multiplier}*PTS' {video_id}-warped.mp4"
    print(cmd)
    os.system(cmd)

def combine_files():
    cmd = f"ffmpeg -i {video_id}-warped.mp4 -i {audio_id}.flac -c:v copy -c:a aac -map 0:v:0 -map 1:a:0 final-output.mp4"
    print(cmd)
    os.system(cmd)

def cleanup():
    cmd = f"rm {video_id}* {audio_id}*"
    print(cmd)
    os.system(cmd)

if __name__ == "__main__":
    main()