1855573 - Allow an opaque compositor native surface to be topmost if nothing is overlaying it.

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, enhancement, P3)

Description

[Brad Werth [:bradwerth]]

Bug 1849680 forced all opaque compositor native surfaces to the bottom of the layer stack to allow content to be rendered on top. This is necessary for non-rectangular video surfaces, but is applied even for unmasked video, which doesn't require this layering. Unfortunately, forcing all video to the bottom layer prevents some useful optimizations such as:

1. Native color layers in Bug 1731136
2. macOS video low power mode in Bug 1653417

test_video_low_power_telemetry.html was disabled in Bug 1849680 for these reasons. This Bug covers the work to re-enable these optimizations and the test which confirms those optimizations are in place.

Comment 1

[Brad Werth [:bradwerth]]

Attachment: Bug 1855573 Part 1: Sometimes promote YUVImage surfaces as overlays.

Using a native surface as an underlay blocks some optimizations, so we
want to do it only when required. This patch checks to ensure that we
only use a surface as an underlay if it is masked. The existing code
already ensured that only opaque surfaces could be underlays.

Comment 2

[Brad Werth [:bradwerth]]

Attachment: Bug 1855573 Part 2: Re-enable test_video_low_power_telemetry.html.

Depends on D189441

Comment 3

[Brad Werth [:bradwerth]]

This is failing, at least in part, at least in some simple test cases, because of this check https://searchfox.org/mozilla-central/rev/9c65def36af441133c75a44b126e65184b039b2f/gfx/wr/webrender/src/picture.rs#2505 which is determining that the transform generated by SpaceMapper has an unexpected structure. When this check fails, the video is unable to be promoted to a surface and its frame contents are merged into the surrounding tiles. I'll try to get past this blocker.

Comment 4

[Brad Werth [:bradwerth]]

The transform check is failing videos with metadata indicating that they are rotated. Not a common case, though important to fix. There's more to find here.

Comment 5

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

There are some r+ patches which didn't land and no activity in this bug for 2 weeks.
:bradwerth, could you have a look please?
If you still have some work to do, you can add an action "Plan Changes" in Phabricator.
For more information, please visit BugBot documentation.

Comment 6

[Brad Werth [:bradwerth]]

Patches need rework and I'll mark them as such.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/2418f8f766d4
Part 1: Sometimes promote YUVImage surfaces as overlays. r=gw
https://hg.mozilla.org/integration/autoland/rev/8fe75e83fbae
Part 2: Re-enable test_video_low_power_telemetry.html. r=gw

Comment 8

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/2418f8f766d4
https://hg.mozilla.org/mozilla-central/rev/8fe75e83fbae