1129261 - HTML5 video playback stutters very badly in FF35

Status: RESOLVED FIXED

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

Description

[Misty De Meo]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:34.0) Gecko/20100101 Firefox/34.0
Build ID: 20141126041045

Steps to reproduce:

View any HTML5 video on any webpage (for instance, Youtube in HTML5 mode, or Vine). A sample video that reproduces this problem: https://www.youtube.com/watch?v=1s5-ODUA-Cc


Actual results:

Video performance is extremely poor; while sound plays back normally, the video stutters and freezes for up to a second at a time.

I have also tested Firefox Beta, Developer Edition, and Nightly, and all exhibit the same behaviour as Firefox 35.


Expected results:

Video playback should be smooth.

Firefox 34, with HTML5 H.264 video enabled, is able to play back the same videos without problems, as are other browsers installed on my system (Safari, Chrome).

Comment 1

[nakoudo]

I am experiencing a similar problem; I'll try my best to explain what I'm seeing here.  I can provide video of the problematic behavior if desired.

I am running Firefox 35.0.1 on a late 2010 Macbook Air (1.4 GHz Core 2 Duo, 2 GB RAM) running OS X 10.8.5.  I have played back comment 1's sample video (https://www.youtube.com/watch?v=1s5-ODUA-Cc) and a 720p sample (https://www.youtube.com/watch?v=wrNTOo4KH8c) in Firefox 35.0.1, Firefox 34, and Chrome 40.0.2214.94.  In all cases, I am using YouTube's HTML5 video player.

With both videos, the video plays smoothly for about a second, but then begins to stutter very badly.  Audio playback remains smooth.  If I let the videos continue to play, the video framerate eventually recovers.

Chrome 40.0.2214.94 is able to play both sample videos at full framerate, as is Firefox 34.  (However, YouTube doesn't offer me a 720p choice in Firefox 34, so I have not yet tested that.)

Comment 2

[Anthony Jones (:ajones, :kentuckyfriedtakahe, :k17e)]

There have been a number of significant improvements in video playback on Mac since this bug was filed. It it working really well so I'm going to close this bug. Re-open if it is still an issue.

Comment 3

[nakoudo]

Hello,

Just tried both testcases in comment 1 and 2 in Firefox 42, same late 2010 Macbook Air (it's since been updated to OS X 10.11.1, though).  Playback is indeed much smoother for me, and audio/video sync appears dead-on.