YouTube Fullscreen Choppy Playback with mid 2011 iMac

EeZeEpEe wrote:

Hello,

It's not my internet connection because I've even let the video load completely. Also when I exit fullscreen, it's perfectly smooth.

I don’t think you have not received an answer because people are ignoring you. It’s just something that must stump people since your machine shouldn’t be at fault. You can play 720p and 1080p video on the iMac from YouTube perfectly smoothly until you select the full-screen display option in the YouTube Window and then it stutters throughout the video playback? But other companies’ video is smooth on Full-screen!

From the Apple menu, select About This Mac. In the Hardware section, look at Graphics. Does everything look normal there? Does the problem occur the first time you play video after you have completely shutdown your computer?

It probably is a Flash issue, remember Apple no longer pre-loads computers with Flash. If a user wants or needs it they are free to download it from Adobe.

EeZeEpEe wrote:

So I'm pretty sure it's Flash but I don't know why it's specific for YouTube.

With those specifications on your machine, you should be handling any video with ease unless the video itself has issues. That is strange that the choppiness is only on YouTube fullscreen. Perhaps the version of the encoded Flash on YouTube is not the same quality as the other sources you play without issue. Good you have a solution... HTML5!

Have the same machine and have the exact same problem. It's not restricted to YouTube, it seems to be any fullscreen Flash video. It is related to Safari as I can watch fullscreen Flash videos in Firefox and Camino.

It's an older version of Firefox (3.0.19), not sure if that makes a difference.

Still annoying as Safari is my default browser and would prefer to use it for fullscreen Flash videos.

Maybe an update will fix it, in the meantime I've opted in for the HTML5 version of YouTube. It doesn't quite give full screen, but it does allow you to make it the full size of the browser, so you can make it nearly as big.

Flash has always had the wrong permissions. Rebuild your permissions and see if that helps. Worth a try...

I did an update today, I think it's made a little difference. There was one for Safari and one specific to our iMacs.

I wouldn't say it's ultra smooth but it's watchable in fullscreen.

EeZeEpEe wrote:

You talking about repairing permissions with Disk Utility? If so I gave it a try and no luck.

You can also Repair Permissions from the Install disc that came with the computer.

OK, seemed to work fine for a bit, but now its gone back to how it was.

Now Firefox is doing the same thing.

To watch any Flash video in fullscreen I have to open it in Camino.

I seem to get some improvement when I restart Safari, but eventually it goes back to the way it was.

Interesting note, whenever I go fullscreen with in Flash, Activity Monitor shows Flash Player (Safari Internet plug-in) shows 100% CPU usage.