Closed Bug 1221942 Opened 9 years ago Closed 8 years ago

Repeated painting in "Live WebVTT Viewer" causes too much CPU usage

Categories

(Core :: Audio/Video: Playback, defect, P3)

Product:
Core
Component:
Audio/Video: Playback
Platform:
x86
macOS
Type:
defect

Tracking

()

Status:
RESOLVED WORKSFORME
Tracking Flags:
Tracking Status
firefox45 --- affected

People

(Reporter: zcorpan, Unassigned)

Details

Using Firefox Nightly 44.0a1 (2015-10-20)

1. Go to https://rawgit.com/zcorpan/live-webvtt-viewer/53d360d8225fc980778ebdd03d5e6f6a0cae5ef9/index.html
(snapshot version of https://zcorpan.github.io/live-webvtt-viewer/ at the time of reporting this bug)
2. Type an "x" or whatever at the end of the "VTT" textarea.
3. Click "Save to address bar".

Actual result
Something causes Firefox to use more CPU than without doing step 3 above.

In devtools, I tried adding breakpoints in the script, and AFAICT the script is just run once when clicking the button, as intended; it's not looping "onhashchange" or anything.

In the performance profiler, things are a-OK before clicking the button, but after clicking the button there is a lot of painting going on.

(I don't know whether this applies on all platforms.)
Component: Audio/Video → Audio/Video: Playback
Priority: -- → P2
Mass change P2 -> P3
Priority: P2 → P3
Can't reproduce anymore in 49.0a1 (2016-05-25)
Status: NEW → RESOLVED
Closed: 8 years ago
Resolution: --- → WORKSFORME
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