video from websites plays a few seconds only .Why ?

[Oldfarmermac]

Yesterday it worked fine viewing any posted video. Today it plays a few seconds and stops but I can move the cursor up and see still frames after the first few seconds that do play.

I presume I have activated a command to make this happen by accident but have no idea what I have done. Any help greatly appreciated.

 

[Oldfarmermac]

I forgot to say so but I have no audio in addition to the frozen video.

 

[Kaveman]

If it's the same video I'd recommend clearing Safari's cache. (Safari Menu)

There is no "command" to do this.

 

[Kaveman]

And there looks like there's a flash update...