Well I looked for an answer to this issue we are having and in another post on another website, somebody mentioned that its probably due to OSX wanting to use integrated graphics for decoding these types of files first before going to dedicated cards when more power is needed. And because we have hackintoshes and we put the dedicated graphics cards first in the boot order, OSX gets confused and so we get garbled video, and also from my original pictures, garbled icons.
Anyway the post goes on to say to put the settings back to igfx first. Which as we probably know, will mean the boot loader screen will not show up if you have your monitor plugged into the dedicated card. In my case as was the author of the post, I have Clover set to boot to OSX and I have windows 8.1 as a secondary (2 positions to the right). I can probably still boot to both either way, but without touching anything it boots to OSX which I run 99 percent of the time.
Once I made the change, my video playing in youtube on safari (which usually always started off garbled) was fine. As for the icons which I mentioned in my previous post as if that was the only issue, those were fixed afterwards by simply renaming the files. As you can compare to my original post.
