Open Bug 1785188 Opened 2 years ago Updated 2 years ago

Firefox window flashes / flickering in the video area. Intel UHD 600


(Core :: Graphics: WebRender, defect)

Firefox 103





(Reporter: ngfield, Unassigned, NeedInfo)


(Blocks 1 open bug)



(1 file)

16.75 KB, application/vnd.oasis.opendocument.text

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:103.0) Gecko/20100101 Firefox/103.0

Steps to reproduce:

Video stream playback - online TV, e.g.

Actual results:

During playback, what's behind the Firefox window flashes / flickering in the video area. The desktop or another application window open below it.
This occurs in normal mode, fullscreen mode, and PIP.
I've been seeing this for the last 2 to 3 updates.
It is no longer usable for watching video.

Especially if you ignore my report of jerky rendering - bad V-sync - when playing video. All browsers have that bad rendering, but Firefox is the worst.

Expected results:

So that what's behind the browser window doesn't flash below the video area.

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

Component: Untriaged → Graphics: WebRender
Product: Firefox → Core

GPU Intel UHD 600 - driver, Windows 10 Pro 21h1, build 19043.1826

This happens irregularly at intervals of 10 s to 4 min.
Sites where I've noticed this e.g.:
etc. - simply live tv streams - I'll try YT too

Severity: -- → S3
See Also: → 1785146

But that's an entirely different thing (bug 1785146).

Well, if you give essential functional things the lowest priority, your users will really just dwindle.

Danial, please attach your about:support output to this report when you get a chance.

Flags: needinfo?(ngfield)
Attached file Firefox-Daniel.odt

Here is about:support output

Flags: needinfo?(ngfield)
Blocks: gfx-triage

What's in it for me?

Daniel, can you try finding a regression window to see what change started causing this problem using the mozregression tool?

Flags: needinfo?(ngfield)

I was looking at the tool and realized it wasn't going to be that simple in this case - always had to start the stream and watch until it showed up. That would be very tedious and take an extreme amount of time.
However, it is certain that this did not manifest before version 100 - my guess is that it came with some recent subversion of 101 or early 102 (my "favorite").
And it hopefully won't be such a problem for you to compare the code changes and pick out the ones related to video playback.
Behind the video area, whatever mode it's in (in page, fullscreen, PIP) the background flashes - what's behind the FF window - for me it's the desktop, because when I watch netTV I only have FF running. If there's another app window, it's visible in the flash.
I've tried a different Chromium based browser in the last 3 versions and everything is fine in that regard.
If the time works out, I'll give it a try, but please don't count on it.
Thank You.

Flags: needinfo?(ngfield)

Can you try setting gfx.webrender.dcomp-video-overlay-win in about:config to see if that fixes the problem?

Flags: needinfo?(ngfield)

Thanks for the tip.
I tried something and now I'm testing if it helped. Once I'm sure, I'll provide information. If I´ll unsuccessful, I´ll try this setup. If possible, I will try the tool as well.

Flags: needinfo?(ngfield)

gfx.webrender.dcomp-video-overlay-win true
gfx.webrender.dcomp-video-overlay-win-force-enabled false
gfx.webrender.dcomp-video-vp-scaling-win true
gfx.webrender.dcomp-video-yuv-overlay-win true
gfx.webrender.dcomp-win.enabled true

Is it OK?

I tested on a basic clean profile and for 2 days everything seemed fine. Then the problem started to occur again, but in a different form. This time there are no background flashes (brief transparency) behind the FF window in the video area, but the entire window flashes fully white, regardless of whether there is video content or not.

Sorry, I wasn't clear in comment 10. Can you try setting gfx.webrender.compositor to false and restarting.

You may also try updating your driver it appears to be from April 2019

Summary: Firefox window flashes / flickering in the video area. → Firefox window flashes / flickering in the video area. Intel UHD 600

I've noticed that this transparency flicker phenomenon appears when Firefox is freshly launched. Before the tab that is last active or the default FF window loads, the entire area from the tabs and address bar down briefly shows the icons I have on my desktop.
I have disabled the window header display. Version already 104.0.
The gfx.webrender.compositor settings have been changed.

I set gfx.webrender.compositor to false and there was no flickering. However, I haven't had a chance to watch the video long enough for it to maybe show up.
What happened today, though, was that I had FF open and the FF startpage in it, and when I moved my mouse somewhere over the top left corner at the border between the FF window and the Windows main bar, it flashed on the desktop much more prominently - the whole FF window went out for a moment.

The described problem initially appears right after starting FF - the window is displayed and before the bookmarks and their contents are loaded, the contents of the window momentarily disappear and the contents behind it - e.g. the desktop area with icons - become visible. And then it was repeated mainly while watching the vidoestream in the browser and sometimes during some mouse cursor movement in the FF area.
Since I switched that webrenderer setting or after the upgrade - I am not able to distinguish, the problem appears, outside of the start itself, very very sporadically anymore.

No longer blocks: gfx-triage

Ashley, is going to try to reproduce this.

Flags: needinfo?(ahale)

I did try to reproduce this unsuccessfully a couple weeks ago but I'm still thinking about ways to provoke it, as some aspects of this seem very inconsistent with the way DirectComposition works in Firefox - for instance when I start Firefox debug builds (which run very slowly, so are useful in understanding how things proceed) I normally see a mostly blank Firefox window appear with the correct theming (dark theme in my case) but it's like a mockup of how the browser normally looks, then the dcomp surfaces cover up the whole window, so if those surfaces became invisible for example I would expect to see the almost-blank window again, not seeing the desktop.

What I find most interesting is the idea that FF disappears momentarily when starting, which sounds like the video driver is somehow displaying an incomplete set of compositing surfaces when we switch over from a regular window to a grid of dcomposition surfaces, I think there may also be an interaction with the Windows taskbar involved in the steps to reproduce.

Flags: needinfo?(ahale)
Flags: needinfo?(ahale)
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