我写了一个程序来下载YouTube视频：

import yt_dlp
URL = "https://www.youtube.com/watch?v=YV2tUZIZ3Bs"

ydl_opts = {
    "format": f"bestvideo[height<=144]",
    "merge_output_format": "mp4",
    "outtmpl": "/home/lankergd/PycharmProjects/LankerTools/films_test/yez.mp4",
    "quiet": False
}
with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        ydl.download(URL)

在下载和保存的过程中，这些输出会打印到控制台的多行。我想把这些行捕获下来并存储到一个变量中。我该怎么做？

输出如下：

/home/lankergd/PycharmProjects/LankerTools/.venv/bin/python /home/lankergd/PycharmProjects/LankerTools/tests.py 
[youtube] Extracting URL: https://www.youtube.com/watch?v=YV2tUZIZ3Bs
[youtube] YV2tUZIZ3Bs: Downloading webpage
WARNING: [youtube] No supported JavaScript runtime could be found. Only deno is enabled by default; to use another runtime add  --js-runtimes RUNTIME[:PATH]  to your command/config. YouTube extraction without a JS runtime has been deprecated, and some formats may be missing. See  https://github.com/yt-dlp/yt-dlp/wiki/EJS  for details on installing one
[youtube] YV2tUZIZ3Bs: Downloading android vr player API JSON
[youtube] YV2tUZIZ3Bs: Downloading ios downgraded player API JSON
WARNING: [youtube] YouTube said: ERROR - Precondition check failed.
WARNING: [youtube] HTTP Error 400: Bad Request. Retrying (1/3)...
[youtube] YV2tUZIZ3Bs: Downloading ios downgraded player API JSON
WARNING: [youtube] YouTube said: ERROR - Precondition check failed.
WARNING: [youtube] HTTP Error 400: Bad Request. Retrying (2/3)...
[youtube] YV2tUZIZ3Bs: Downloading ios downgraded player API JSON
WARNING: [youtube] YouTube said: ERROR - Precondition check failed.
WARNING: [youtube] HTTP Error 400: Bad Request. Retrying (3/3)...
[youtube] YV2tUZIZ3Bs: Downloading ios downgraded player API JSON
WARNING: [youtube] YouTube said: ERROR - Precondition check failed.
WARNING: [youtube] Unable to download API page: HTTP Error 400: Bad Request (caused by <HTTPError 400: Bad Request>)
[info] YV2tUZIZ3Bs: Downloading 1 format(s): 160
[download] Destination: /home/lankergd/PycharmProjects/LankerTools/films_test/yez.mp4
[download] 100% of  365.55KiB in 00:00:00 at 958.59KiB/s 

Process finished with exit code 0

解决方案

YoutubeDL 支持传递自定义日志记录器。若这样做，下载的输出将写入日志对象，而不是打印到控制台。例如，这个程序将输出写入一个 StringIO 对象以便后续使用：

import io
import logging

import yt_dlp


URL = "https://www.youtube.com/watch?v=YV2tUZIZ3Bs"

logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
yt_dlp_output = io.StringIO()
handler = logging.StreamHandler(yt_dlp_output)
handler.setLevel(logging.DEBUG)
logger.addHandler(handler)

ydl_opts = {
    "format": "bestvideo[height<=144]",
    "merge_output_format": "mp4",
    "outtmpl": "yez.mp4",
    "quiet": False,
    "logger": logger
}


with yt_dlp.YoutubeDL(ydl_opts) as ydl:
    ydl.download(URL)

yt_dlp_output.seek(0)
for line in yt_dlp_output:
    print(line)