使用youtube-dl下载YouTube音频遇URL无效错误，求解决方案

我想用youtube-dl仅下载YouTube视频的音频，误以为将命令中的参数-o替换为-x即可实现该功能，但实际操作时出现错误（使用参数-q时无此错误），错误提示如下：

'~/Desktop/Music/name.%(ext)s' is not a valid URL. Set --default-search "ytsearch" (or run youtube-dl "ytsearch:~/Desktop/Music/name.%(ext)s" ) to search YouTube.

以下是我的Python代码，希望获得解决建议：

from os import system
import sys
from selenium import webdriver
from selenium.webdriver.common.by import By

def titleCase(s):
    '''
    A function to convert the given song name to title case.
    The default function in Python convert the words 'the', 'and', 'of', etc.
    And I find that annoying
    '''

    l = s.split()
    str = l[0][0].upper() + l[0][1:]
    
    for word in l[1:]:
        if word not in ['in', 'the', 'for', 'of', 'a', 'at', 'an', 'is', 'and']:
            str += ' ' + word[0].upper() + word[1:]
        else:
            str += ' ' + word
    
    return str


def getVidID(song, URL):
    '''
    This function gets the ID of the Video you have to download.
    '''
    driver = webdriver.Chrome()
    driver.implicitly_wait(5)
    links = []
    search = song + ' lyrics'
    searchQuery = '+'.join(search.split())
    searchURL = URL + searchQuery
    driver.get(searchURL)
    link_webelement = driver.find_element(By.CSS_SELECTOR, 'div#contents ytd-item-section-renderer>div#contents a#thumbnail')
    links += [link_webelement.get_attribute('href')]
    vidID=links[0]
    return vidID

def doStuff(song):
    print("Downloading " + titleCase(song))
    URL = 'https://www.youtube.com/results?search_query='
    link = getVidID(song, URL)
    pathToSave = "~/Desktop/Music/"+titleCase(song)
    system("youtube-dl -o \'" + pathToSave + ".%(ext)s\' \'" + link + "\'")
    print("Downloaded " + titleCase(song) + "\n") 

def main():
    print('-------------------------------------------------------------')
    if (len(sys.argv) == 3 and (sys.argv[1] == '-i' or sys.argv[1] == '-I')):
        for song in open(sys.argv[2]).readlines():
            doStuff(song)

    else:
        for song in sys.argv[1:]:
            doStuff(song)

if __name__ == '__main__':
    main();

问题原因 #

你误解了参数用法：-x是提取音频的参数，并非用来替换-o。两者是配合关系，而非互斥替换——-o负责指定输出路径，-x负责将视频转换为音频格式。错误出现是因为你只传入-x加路径，youtube-dl误将保存路径识别为要下载的URL，因此抛出无效URL的错误。

修复方案 #

1. 修正youtube-dl命令参数
   修改doStuff函数中的命令，同时保留-x和-o参数：

system("youtube-dl -x -o \'" + pathToSave + ".%(ext)s\' \'" + link + "\'")

2. 处理文件名中的换行符
   readlines()会保留每行末尾的换行符，导致文件名包含无效字符，需在doStuff开头添加字符串清理：

def doStuff(song):
    song = song.strip()  # 去除首尾空白和换行符
    print("Downloading " + titleCase(song))
    # 后续代码不变

3. 关闭Chrome浏览器进程
   getVidID函数中使用完浏览器后未关闭，会残留大量进程，需添加关闭逻辑：

def getVidID(song, URL):
    driver = webdriver.Chrome()
    try:
        driver.implicitly_wait(5)
        links = []
        search = song + ' lyrics'
        searchQuery = '+'.join(search.split())
        searchURL = URL + searchQuery
        driver.get(searchURL)
        link_webelement = driver.find_element(By.CSS_SELECTOR, 'div#contents ytd-item-section-renderer>div#contents a#thumbnail')
        links += [link_webelement.get_attribute('href')]
        vidID=links[0]
        return vidID
    finally:
        driver.quit()  # 确保浏览器进程被关闭

4. 过滤文件名特殊字符
   若歌曲名包含/、:等系统禁止的字符，会导致路径无效，可添加过滤逻辑：

import re  # 需在文件顶部导入re模块

def doStuff(song):
    song = song.strip()
    formatted_title = titleCase(song)
    # 过滤文件名中的特殊字符
    safe_filename = re.sub(r'[^\w\s-]', '', formatted_title).strip()
    pathToSave = "~/Desktop/Music/" + safe_filename
    # 后续代码不变

内容的提问来源于stack exchange，提问作者Christopher Panizzolo