embedded video not shown in safari 7.1

[sheppy]

Hello,

I have updated Safari to latest version (7.1) om a Mac running 10.9.5 (all up to date).
And now, no embedded video/Youtube is shown on any site. Just empty blank space shown.
This is a screenshot of the following site:
https://www.macrumors.com/2014/09/22/apple-huge-cameras-ads/

The screenshot of Safari 7.1:

This is the screenshot using Firefox:

I have disabled all extensions in Safari, but still they do not show up.
I have tested in both the standard video player and the HTML5 player for Youtube.
Please help me with this.

Thanks in advance.

Kind regards,

Sjoerd