1687119 - Subtitle (WEBVTT) with a style is not correctly loaded (new issue from the last update?)

Status: UNCONFIRMED

(Core :: Audio/Video: Playback, defect, P3)

Description

[T4]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:84.0) Gecko/20100101 Firefox/84.0

Steps to reproduce:

I open page: https://learngerman.dw.com/en/berufswahl/l-38215363 and play the video with subtitle on.

Actual results:

After the last 1 or 2 updates, the subtitles cannot be correctly displayed.

Expected results:

The subtitle on the video shall be correctly displayed.

problematic video: https://learngerman.dw.com/en/berufswahl/l-38215363
but one other video can be played with subtitle correctly: https://learngerman.dw.com/en/lebenslinien/l-38051792

I compared the subtitle for the first video: https://learngerman.dw.com/media/subtitles/56236290
and the one from the second: https://learngerman.dw.com/media/subtitles/43805119

There is a difference in the format/style. But I am not sure if this is the reason.

It looks like this issue was brought from the last one or 2 updates. Could you please have a look?
Thanks.

Comment 1

[T4]

Firefox version: 84.0.2 (64-bit) on Windows 10

Comment 2

[T4]

I downloaded the latest nightly build: 86.0a1 (2021-01-16) (64-bit)
This problem exists.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 4

[Alastor Wu [:alwu]]

This failure occurs in the process of calculating CSS style for region elements.