4.12.2/4.11.14 introduces subtitles with HLS streams being out of sync

[markuswolters]

Have you read the FAQ and checked for duplicate open issues?
Yes

If the problem is related to FairPlay, have you read the tutorial?

N/A

What version of Shaka Player are you using?
v4.12.2

Can you reproduce the issue with our latest release version?
Yes

Can you reproduce the issue with the latest code from main?
Yes

Are you using the demo app or your own custom app?
The demo

If custom app, can you reproduce the issue using our demo app?
N/A

What browser and OS are you using?
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

For embedded devices (smart TVs, etc.), what model and firmware version are you using?
N/A

What are the manifest and license server URIs?
HLS-Stream-Url

What configuration are you using? What is the output of player.getConfiguration()?

Using demo site with custom url: Demo Custom Content

What did you do?

• Updated from Shaka 4.12.1 to 4.12.2 and noticed bug.
• Tried to replicate with demo site (Custom content)
• Selected play
• Selected subtitle "German"
• Narrowed down to bug being introduced with 4.12.2/4.11.14

What did you expect to happen?
Subtitles should be displayed at correct timings according to srt-files.

What actually happened?
With the latest Shaka release subtitles for our HLS streams started to get out of sync. In the HLS stream provided, "Hallo wie geht es dir?" should be displayed at timestamp 02:41, however, it starts at 2:52, see screenshot:

SRT extract:

1
00:02:39,958 --> 00:02:41,375
Hallo!

2
00:02:41,542 --> 00:02:43,167
Hallo, wie geht es dir?

I'm wondering, if this has been introduced with fix(HLS): Fix subtitle timing #7625, as this fix has beed added to both 4.12.2 and 4.11.14, which both have the same issue.

4.12.1 and 4.11.13 show subtitles at correct timings.

Tested with HLS.js as well, works as expected.

Are you planning send a PR to fix it?