MCE View: CPU spike when using [video] embed for an MP4 in Chrome

[jeremyfelt]

Chrome 33.0.1750.152, OSX 10.9.2

As of the bump from MediaElement 2.13.2 to 2.14.0 in [27811], the display of an embedded MP4 with [video] in MCE spikes processor usage to 100% and crashes the tab in Chrome.

If I revert back to 27810, the view works as expected. If I use MediaElement 2.13.2 with current trunk, the view also works as expected.

If I use the [playlist] shortcode, everything works beautifully in trunk with 2.14.0. This new media stuff is fantastic. :)

Safari 7.0.2 freezes as well, though I haven't tested it extensively.
Neither Opera or Firefox freeze, though both show only text - ​https://cloudup.com/c2A2VMbeDkG

[jeremyfelt]

I think I've traced this to commit ​a7f67b718 in MediaElement.

This scenario puts while (lastControlPosition.top > 0) into an infinite loop.

[jeremyfelt]

It seems like the initial page load results in two MediaElement view requests.

In the first request, a negative rail width (-1896) is set and the position of the fullscreen button is detected relative to the top of the document. This results in a top position of something like 719.12345. This results in an endless loop as the position never changes.

If I detect this first request (based on its negative rail width?) and skip it by returning without completing setControlsSize, a second request is made. In this second request, the rail width is normal (312), the position of the fullscreen button is detected with a top position of 0, and everything works properly.

This same successful request is made when switching between Text and Visual.

[wonderboymusic]

In 27853:

Revert mediaelement-and-player.min.js to a usable build that doesn't cause an infinite loop. Still 2.14.0, minus the offending pull request: ​https://github.com/johndyer/mediaelement/commit/a7f67b71800af1dd742162f1be3ffe401b72b1f9

Reported upstream. 2.14.0 is necessary for playing m4a files properly. 2.14.0 with the offending pull request is unusable in Chrome.

See #27582.

[wonderboymusic]

In 27861:

MEjs has been fixed upstream: ​https://github.com/johndyer/mediaelement/commit/1a75559c9d9ada344fee7a6f5f08ccc1e4b0fbfa
No more infinite loop.

This restores MediaElement to a clean build: 2.14.0.

Fixes #27582.
Thanks to jeremyfelt for tracking this down.

[johndyer]

Thanks guys. This fix has been labeled as MediaElement.js 2.14.1 so that it matches up in Wordpress and other non-Wordpress sites.

[wonderboymusic]

There is another maintenance release related to this issue: 2.14.2. Patch attached. I studied the changes, all looks good.

[nacin]

Cleared by me. Waiting for azaozz.

[wonderboymusic]

2.14.2

​https://github.com/johndyer/mediaelement/commit/7d0962ef2ae86c692b0566a5ae5f0cd515b58792

[azaozz]

Looks good. Don't forget to bump the version in script-loader on commit.

[wonderboymusic]

In 28068:

Bump MediaElement.js to 2.14.2. Release Notes: ​https://github.com/johndyer/mediaelement/commit/743f4465231dc20e6f9e96a5cb8b9d5299ceddd3.

Fixes #27582.