KARL doesn’t handle embeding YouTube or Brightcove videos. Below are a few examples of code that should work, but somehow gets mangled by TinyMCE or something else along the way.
BRIGHTCOVE
<object id="flashObj" width="460" height="281" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,47,0"><param name="movie" value="http://c.brightcove.com/services/viewer/federated_f9/9787661001?isVid=1&isUI=1&publisherID=1125929394" /><param name="bgcolor" value="#FFFFFF" /><param name="flashVars" value="@videoPlayer=29291660001&playerID=9787661001&domain=embed&" /><param name="base" value="http://admin.brightcove.com" /><param name="seamlesstabbing" value="false" /><param name="allowFullScreen" value="true" /><param name="swLiveConnect" value="true" /><param name="allowScriptAccess" value="always" /><embed src="http://c.brightcove.com/services/viewer/federated_f9/9787661001?isVid=1&isUI=1&publisherID=1125929394" bgcolor="#FFFFFF" flashVars="@videoPlayer=29291660001&playerID=9787661001&&domain=embed&" base="http://admin.brightcove.com" name="flashObj" width="460" height="281" seamlesstabbing="false" type="application/x-shockwave-flash" allowFullScreen="true" allowScriptAccess="always" swLiveConnect="true" pluginspage="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash"></embed></object>
YOU TUBE
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/iHKcbixwhJs&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/iHKcbixwhJs&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
Balazs, I'm out this week. Can you take a look at the layers in the onion (TinyMCE cleanup, server-side cleanup), diagnose where it is happening, and work on a fix?