Show swf adverts before Your videos.
This code displays the ad for 6 seconds = 6000 miliseconds.
You can change this value to suit Your own settings.

File to edit : /templates/view_video.tpl

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Code:
<script> 
window.setTimeout("document.getElementById('ads').style.display = 'none';document.getElementById('self').style.display = '';",6000); 
</script> 
<div id="ads"> 
<div align="right"><font face="Arial" style="font-size: 10pt; font-weight: 700"><a href="#" onclick="document.getElementById('ads').style.display = 'none';document.getElementById('self').style.display = '';"> 
    <font color="#FF0000">Skip Ads»</font></a></font></div> 
<center> 
<font color="#FF0000"> 
<font face="Arial" style="font-size: 9pt; font-weight: 700">Please Wait...<br> 
</font><img border="0" src="http://img25.imageshack.us/img25/2134/ajaxloader.gif" width="128" height="15"><br> 
Advertisement-swf file code here
</font> 
</div> 
<div id="self" style="display:none";>
Video code/embed code here
</div>
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