You tube has used the light silver theme for it's embedded video player for a long time. E.g. See the frame of the video below.
But now, Youtube has introduced another dark theme for it's video player. The frame color has been changed to a light black color while the red color ot the progress bar is retained. See the same video above in the new theme below.
If you have Youtube videos in your blog or website embedded using the IFRAME tag, you can easily switch to the dark theme for Youtube video player by adding a new parameter called theme to the URL.
For consistent results, set "theme=dark" for the dark theme and "theme=light" for the light silver theme as below.
Light (Silver) Theme:
<iframe src="http://www.youtube.com/embed/S1Q9bAochC0?theme=light
frameborder="0" width="640" height="510"></iframe>
Dark (Black) Theme:
<iframe src="http://www.youtube.com/embed/S1Q9bAochC0?theme=dark
frameborder="0" width="640" height="510"></iframe>
Please note that the new theme option is available only for the "IFRAME" version and not for the old "OBJECT" based embed codes.
The default theme for the Youtube video player has already been changed to the dark one in Youtube.com. Youtube has also said it would switch to the dark theme as default for all embedded videos in other web sites as well in the coming days.
That means if you are a fan of the old silver skin and would like to retain it, you would have to add "theme=light" to existing Youtube embeds in your web pages.