821984 - HTML5 is using unexpectedly high CPU during playback that causes micro-stuttering on Linux

Status: RESOLVED INACTIVE

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

Description

[mikey]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20100101 Firefox/17.0
Build ID: 20121130221340

Steps to reproduce:

1) Go to http://www.youtube.com/html5 and join trial
2) Make sure Linux ondemand CPU frequency scaling governor is active
3) Find a video and watch in HD Fullscreen for example:

http://www.youtube.com/watch?v=eRsGyueVLvQ
or
http://www.youtube.com/watch?v=2yj0e0r_yLI 

4) Observe stuttering during playback
5) Compare to Flash or HTML5 in Chromium where stuttering is not present
6) Change to performance CPU scaling governor for stable CPU frequency
7) Run "top" and watch CPU usage while playing HTML5 in Firefox
8) Compare to Flash and other HML5 Browsers 


Actual results:

Here is a Video showing the CPU usage on my computer (I've not tried recording the video stuttering, though I can assure you it's very apparent on fullscreen): 

https://dl.dropbox.com/u/38280833/FirefoxHTML5webm

What I found is that the stuttering with Firefox appears to be caused by a much higher CPU usage than with either Flash or HTML5 on Chromium (or Epiphany). I found that HTML5 for Firefox used approximately 26-30% CPU @ 3.6 GHz, while Flash used 9-15% and HTML5 for Chromium used 9-11%.

PS my Graphics card is a GeForce GTX 660 Ti 3Gb with the NVidia 310.19 drivers. Running on Fedora 17, kernel 3.6.9-2.fc17.x86_64. 


Expected results:

Playback for HTML5 under Firefox should be smooth as it is with HTML5 on other browsers and should use a similar proportion of CPU power. It certainly should not be showing poorer playback than Flash and double the CPU use of Flash which it is supposed to be supplanting to provide the advantages of compilation optimization for better playback.

Comment 1

[mikey]

Putting CPU into performance mode removes the stutter but not the CPU use and should not be required as it is not for other HTML5 browsers or Flash video.

Comment 2

[Nils Ohlmeier [:drno]]

Mass closing because of inactivity.
Please feel free to re-open if still relevant.