Last modified: 2012-12-17 14:49:26 UTC
Today, a 26MB video file was featured on the English Wikipedia main page, see URL field above. Clicking the "play" button in Firefox causes the browser to become unresponsive, using 100% of one core. The browser does respond to clicks after a delay of 10s or so, but never appears to repaint. Closing the tab is possible and causes the CPU usage to stop. Observed with the current version of Firefox on Ubuntu 12.04, with a default profile and in safe mode. Playing the same file using Firefox's video capabilities but without TMH involved does work. Once the file is loaded into the browser's cache, the bug stops happening and the video will play correctly. The bug can be reproduced again by clearing the cache with the "clear your recent history" feature. I tried enabling EmbedPlayer.NativeControls but it didn't help.
Played without issue on first load, no cache mode & cleared cache. ( Ubuntu 12.04, Firefox 15.0.1, pulse audio ) What version of Firefox are you using and what audio back-end ? Does it do it for webm files: http://commons.wikimedia.org/wiki/File:2012-07-18_Market_Street_-_San_Francisco.webm Does it do it when you disable javacript ( and just play the asset inline ) ?
(In reply to comment #1) > Played without issue on first load, no cache mode & cleared cache. ( Ubuntu > 12.04, Firefox 15.0.1, pulse audio ) > > What version of Firefox are you using and what audio back-end ? $ dpkg-query -W firefox firefox 16.0.2+build1-0ubuntu0.12.04.1 PulseAudio is installed, but the file has no sound and pavucontrol shows no open streams while it is playing. > Does it do it for webm files: > http://commons.wikimedia.org/wiki/File:2012-07-18_Market_Street_-_San_Francisco.webm No. > Does it do it when you disable javacript ( and just play the asset inline ) ? Yes. With JavaScript disabled, the video has no controls, but there is a "play" item in the context menu. Clicking it causes the issue, and it even persists after the tab is closed. After closing the tab, it takes about 45 seconds for the browser to become responsive again. If I play the video by navigating directly to <http://upload.wikimedia.org/wikipedia/commons/d/d0/Webcam_CT_transmissions.OGG> it works, so I guess it just affects <video>.
Fedora 16, Firefox 16.0.2: URL "about:memory" shows that allocated memory slowly increases, but I don't see any such lag. Memory is freed again after video has finished playing.
from http://news.ycombinator.com/item?id=4762181 it looks like this is a Firefox bug that was fixed and might be backported to 16
On the bright side by default we prefer WebM so once all the transcoding is completed the error should be less common ( unless you select the ogg source ) Jan do we have a bug for prioritizing a particular file transcode? We should be able to do that for blog posts, fundraiser, featured videos etc. This way prominent videos have all their derivatives. This may be less-necessary once the backlog is proccessed. But still useful for say; if we enable h.264 and want to do a blog post showing the video working on iPhones.
Firefox 17 is the stable version now and fixes this issue, in addition we have webm transcodes now. closing this bug.
