Require Information regarding Youtube Embed

[softleaks]

When I embed a youtube video to wjunction some strings are appended in the embed source.

For example:

[ame]http://www.youtube.com/watch?v=JByDbPn6A1o[/ame]


When you look at the Embed code for the above video you will find something like this:

<object width="425" height="350">
<param name=''movie'' value="http://www.youtube.com/v/JByDbPn6A1o&amp;ap=%2526fmt%3D18&amp;fs=1"></param>
<param name="allowFullScreen" value="true"></param>
<embed src="http://www.youtube.com/v/JByDbPn6A1o&amp;ap=%2526fmt%3D18&amp;fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="350" wmode="transparent"></embed></object>

I wanna know why is the string,

&ap=%2526fmt%3D18&fs=1

appended at the end of the video link and what does it mean???

 

[soft2050]

fs=1

This enables full screen button to be shown. More here: https://developers.google.com/youtube/player_parameters#fs

ap=%2526fmt%3D18

This is used to show high quality source of video