1958650 - Twitch streams taking longer to start

Status: UNCONFIRMED

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

Description

[Okarin]

Steps to reproduce:

• open twitch.tv, you should have a random stream that start playing
• hover the video, click on pause
• wait a few second
• click on play

Actual results:

Video playback take a significantly longer time to start than previously (~1s or more)

Expected results:

Video playback should start almost instantly (~0.5s or less)

Comment 1

[Okarin]

mozregression failed at https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=01a30eea5505e9ed21e2d5b8608a0146d6f6013a&tochange=b2432da9eac82bb1169a19b8019d0843426912a9

build for 01a30eea5505e9ed21e2d5b8608a0146d6f6013a is fine.
b2432da9eac82bb1169a19b8019d0843426912a9 & 75dae18eb4520d41e2b5f4460c74c266b1092684 are not.

Comment 2

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

The Bugbug bot thinks this bug should belong to the 'Core::Audio/Video: Playback' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[Karl Tomlinson (:karlt)]

Thank you for the regression range.
The only thing that changed in that range was the Firefox version, reported to twitch in navigator.userAgent.
That suggests that twitch is choosing to do something different with Firefox 137.

I'm not reproducing here.
Does twitch behave the same whether or not you are logged in?
Does the play icon appear immediately or when the video playback resumes?

Comment 4

[Okarin]

I reran a moz-regression, and the result is still the same range.
I can reproduce this issue on two computers (Windows 10 and Windows 11).
The behavior is the same whether I am logged in or not.
Changing the user agent in about:config changes nothing.

If only the version number changed between these two builds, it's probably Twitch's fault indeed.

Comment 5

[Okarin]

Attachment: 2025-04-08 21-42-03.mkv

I recorded it in a video.
The resulting lag between the two versions is 930ms.
It's not always that significant, though.

Comment 6

[Karl Tomlinson (:karlt)]

Thanks for the recording. I see the play icon appear immediately (and briefly), but then a spinner before playback resumes.

Thank you for changing the user agent too.
I don't know how Twitch would know the version other than through the user agent string.
Could an extension be involved?
Is the behavior the same in troubleshoot mode?