Unable to download subtitles using class YoutubeDL, but works on CLI?

[victorhooi]

Hi,

I'm using the edu_10gen_dl script (https://github.com/nonsleepr/edu_10gen_dl) to download videos, which just calls youtube-dl under the hood.

The videos download correctly, however, the subtitles do not. Output from the script:

Processing lectures/M101P_-_MongoDB_for_Developers/Week_4_-_Performance/04.12.*...
[04.12.01] When is an Index Used? (Lecture)
http://www.youtube.com/watch?v=
Lwms58Y_3Jc
[youtube] Setting language
[youtube] Lwms58Y_3Jc: Downloading video webpage
[youtube] Lwms58Y_3Jc: Downloading video info webpage
[youtube] Lwms58Y_3Jc: Extracting video information
WARNING: unable to download video subtitles for en: Unable to download webpage: HTTP Error 404: Not Found; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.
[download] Destination: lectures/M101P_-_MongoDB_for_Developers/Week_4_-_Performance/04.12.01 When_is_an_Index_Used_Lecture.mp4
[download]  17.6% of 21.28MiB at  1.64MiB/s ETA 00:10

The strange thing is, when I download that same video id (Lwms58Y_3Jc) using the youtube-dl command line client, it works fine:

$ youtube-dl --write-sub Lwms58Y_3Jc
[youtube] Setting language
[youtube] Lwms58Y_3Jc: Downloading video webpage
[youtube] Lwms58Y_3Jc: Downloading video info webpage
[youtube] Lwms58Y_3Jc: Extracting video information
[info] Writing video subtitles to: m101 19 query plans-Lwms58Y_3Jc.en.srt
[download] Destination: m101 19 query plans-Lwms58Y_3Jc.mp4
[download] 100% of 21.28MiB in 00:12

However, when the edx_dl.py imports from the youtube-dl library, it does not work:

from youtube_dl.YoutubeDL import YoutubeDL
...
        self._fd = YoutubeDL(config.YDL_PARAMS)
...
                    self._fd.download([video_id])

In this case, video_id is simply the unicode string "Lwms58Y_3Jc".

I was wondering, is there some difference in behaviour between calling the youtube-dl command line client, versus important YoutubeDL and calling .download() with a video id?

Or anything else that might explain the above behaviour?

Thanks,
Victor

[jaimeMF]

It should be fixed now, we didn't set a default value for the subtitles format, this produced that the subtitles urls have the fmt=None in the them, that caused the 404 error.
If you find any other issue when using youtube_dl from python code, please open a new issue, we'd really appreciate it.
Thanks for the report!

There are some differences when using YoutubeDL manually, for example:

• You have to manually add the post processors.
• You should considere setting the url openers (youtube_dl._setup_opener), for handling cookies and gzipped pages.

But apart from that, they should behave the same, in that case if any field is missing in the params dict. there should be a default value.