Entire subtitles are shown in the first few seconds for some videos

[the-blank-x]

Expected behavior: Subtitles to be readable throughout the entire video

Actual behavior: The entire subtitles are shown in the first few seconds, without any more for the rest of the video

Steps to reproduce: Run pipe-viewer https://www.youtube.com/watch?v=_FCZnrUq3N4

Screenshot:

Additional details:
Config: pipe-viewer.conf.gz
The mangled subtitles of videos affected by this bug I've seen: affected-subs.tar.gz

If I set a breakpoint in GetCaption.pm:221 and run p $xml, I get the following output: _FCZnrUq3N4.xml.gz
I've figured out the cause by looking at yt-dlp's source code. If you're fine with that, then open the following section:

In GetCaption.pm:221, if I get $url, remove the tlang parameter, and fetch the URL with wget, the output looks fine. Additional links:

• https://github.com/yt-dlp/yt-dlp/blob/01aba2519a0884ef17d5f85608dbd2a455577147/yt_dlp/extractor/youtube.py#L4324
• Issue with Youtube auto subtitle yt-dlp/yt-dlp#2956 (comment)

[the-blank-x]

Given that there's a commit that uses code from yt-dlp, I'm assuming that using information from yt-dlp to fix this bug is fine? If so, let me know so that I can take a jab at this

[trizen]

As far as I know, it's an YouTube issue.

[the-blank-x]

Yes, but I cannot reproduce this with yt-dlp and Newpipe (should've mentioned this in the issue, oops), and it seems to be fixable (haven't tried it yet, but see the Additional details section)

[trizen]

The subtitle is offered by YouTube on (at least) 3 different formats. Probably only the format pipe-viewer uses is affected. If true, then switching to a different format would fix the issue.

Edit: the issue occurs when tlang=LANG parameter is used, which we use to auto-translate subtitles.