Styling of controls in demo shouldn't be modified when not visible

[jbauman2]

See also https://bugs.chromium.org/p/chromium/issues/detail?id=704673#c1

• What version of Shaka Player are you using?
  2.0.7-debug from https://shaka-player-demo.appspot.com/demo/

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

• What browser and OS are you using?

Chrome Canary on Windows 10

• What did you do?
  Loaded shaka player, started a video, and turned on "Paint Flashing" from the "Rendering" tab of Chrome's dev tools

  • What content did you load?

    • If standard demo asset, which one?
      Sintel 4k (WebM only)

  • How did you interact with the content, if at all?
    No, just waited for the controls to disappear

• What did you expect to happen?
  Once the controls hide, only the entire video should flash green.

• What actually happened?
  On alternating frames, either the entire video flashes green or the area where the seekBar is flashes green.

These unnecessary updates to the seekbar take CPU (for styling and layout) and GPU time (to draw frames that don't actually change anything. The demo app should avoid updating properties and style of the seekBar and other CSS elements when they're supposed to be hidden.

I think all calls to ShakaControls.prototype.updateTimeAndSeekRange_ should be deferred until the controls are made visible. Style and property updates that seem problematic are seekBar_.min, seekBar_.max, seekBar_.value, seekBar_.style.background, and currentTime_.textContent .

[joeyparrish]

As I understand it, this also means the demo app is consuming more battery than it should on mobile devices and laptops. Is that correct?

[jbauman2]

Yeah, that's right. And in the future it will prevent Chrome from using overlay to display the video, which save even more power.

…

On Tue, Apr 4, 2017 at 9:52 PM, Joey Parrish ***@***.***> wrote: As I understand it, this also means the demo app is consuming more battery than it should on mobile devices and laptops. Is that correct? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#749 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAruj63Ye3-MYV41Zh9-A4VbASoLmxQaks5rsx38gaJpZM4MznnX> .

[joeyparrish]

@jbauman2 The next nightly build should be much improved: https://nightly-dot-shaka-player-demo.appspot.com/ Thanks!