Download and extract Bilibili audio

download_bilibili_audio.py

import os
from pathlib import Path
import youtube_dl
import sys


def extract_audio(code, audio_name='%(title)s'):
    # extract the audio from a video (with code <code>)

    _opts = {
        'outtmpl': f'{audio_name}.mp4',
        'format': 'bestaudio/best',
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3',
            'preferredquality': '192',
        }],
    }

    with youtube_dl.YoutubeDL(_opts) as ydl:
        ydl.download(['https://www.bilibili.com/video/%s' % code])
    return f'{audio_name}.mp3'


def cut_audio(input_path):
    """ use ffmpeg to cut audio """
    output_path = Path(input_path).parent.joinpath("out")
    output_path.mkdir(parents=True, exist_ok=True)
    output = str(output_path / input_path)
    command = f"ffmpeg -ss 00:00:10 -i {input_path} {output}"
    print(command)
    os.system(command)


method_name = sys.argv[1]

if method_name == "cut":
    print("do cut job.")
    input_file = sys.argv[2]
    cut_audio(input_file)
elif method_name == "download":
    print("do download job.")
    av_no = sys.argv[2]
    name = sys.argv[3]
    extract_audio(av_no, name)
else:
    print(f"invalid argument: {method_name}.")

print("Finish.")