Well I'm glad to see there's others having the same issue with all Firebox based browsers. I did some checking and saw that Mozilla has been making changes with the way media is handled and updating their media controls. Here's what I found:
Our HTML5 media controls have changed very little since they were introduced in Firefox 3.5 -- mostly just bug fixed and keeping them working as the spec evolves. HTML5 media is an area we've made serious investment in, and it's time to make sure our default controls show it.
This project is primarily a collection of bug-fixes, updated design work, and small-scope featurettes; all building on top of the existing implementation.
This feature falls primarily in the Experience category (from the "Discover, Experience, and Connect" vision statement.)
(fixed, FF8) bug 518008 – click on video to pause/play
(fixed, FF9) bug 472942 – Make viewing a video directly look nice.
(fixed, FF10) bug 669260 – add "Show Video Info" context menu (overlay)
(fixed, FF10) bug 681550 – Context menu for Save Video As Image
(fixed, FF10) bug 675899 - HTML5 video player should show controls when video ends (if controls attribute is present)
(fixed, FF11) bug 513405 – Add text to videocontrols to describe the cause of errors.
(fixed, FF11) bug 537718 - Video should scale for a small window.
(fixed, FF11) bug 470628 – Provide a Full Screen button (or Full Tab?)
(fixed, FF12) bug 681548 – Visual refresh of controls
(fixed, FF12) bug 666306 – Video content should become large play button when video is not autoplay and with controls enabled
(fixed, FF8) bug 481082 – Video controls should listen for "stalled" event
(fixed, FF8) bug 669217 – remove nsISecurityCheckedComponent goop
(fixed, FF8) bug 669616 – Time in media rounded incorrectly
(fixed, FF10) bug 556563 – Remove "View Video" context menu when you're already viewing the video
(fixed, FF9) bug 462117 – Add specialized video controls for small-dimension media.
(fixed, FF10) bug 513758 - Pressing Pos1/End key while video is in ended state sets status to play
(fixed, FF11) bug 699719 - Fade out video controls if no mouse movement for > n seconds
So as you can see, work is being done to improve media controls and the way media plays. Some other changes is Mozilla will change to VC2010 to build Firefox after Firefox 13 and they are changing out their code to an improved better code. So lots of changes are being made which will improve Firefox in all areas. By the way, YouTube has recently changed from Flash based videos to HTML 5. This could be what's causing the problems. Take a look at the following link for more info:
I think the problem is YouTube. Google owns both Chrome and YouTube so that's why the video plays perfectly on their browsers. They decided to change from Flash to HTML 5 suddenly and in the process, lots of other browsers are having these issues. Thanks again Google for making your browser look good and screwing everyone else! Anyway, give it a little time and other browsers will completely switch to what Google wants and all video will play smooth again.Edited by djkilla - 4/23/12 at 7:24am