FLVPlayback - How to specify fla source at runtime

Question

I'm a total newbie with Flash.
We want to host video on our site. The video to be viewed is
selected by the user. I wanted to use the FLVPlayback component to
display the video by specifying the source URL of the .fla file at
runtime in the HTML page code. I've no idea how to access the
source property at runtime in the object tag or whatever. Obviously
I need to learn Actionscript to understand it properly, but can
anyone give me a simple example of how it would be done, or point
me to a tutorial on it?
The object tag looks like this:
<object
classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="
http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,0,0"
width="550" height="400" id="viewer" align="middle">
<param name="allowScriptAccess" value="sameDomain" />
<param name="allowFullScreen" value="false" />
<param name="movie" value="viewer.swf" /><param
name="quality" value="high" /><param name="bgcolor"
value="#ffffff" /> <embed src="viewer.swf" quality="high"
bgcolor="#ffffff" width="550" height="400" name="viewer"
align="middle" allowScriptAccess="sameDomain"
allowFullScreen="false" type="application/x-shockwave-flash"
pluginspage="
http://www.macromedia.com/go/getflashplayer"
/>
</object>
There's also a javascript function:
AC_FL_RunContent(
'codebase', '
http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,0,0',
'width', '550',
'height', '400',
'src', 'viewer',
'quality', 'high',
'pluginspage', '
http://www.macromedia.com/go/getflashplayer',
'align', 'middle',
'play', 'true',
'loop', 'true',
'scale', 'showall',
'wmode', 'window',
'devicefont', 'false',
'id', 'viewer',
'bgcolor', '#ffffff',
'name', 'viewer',
'menu', 'true',
'allowFullScreen', 'false',
'allowScriptAccess','sameDomain',
'movie', 'viewer',
'salign', ''
); //end AC code
Is it a matter of dropping in some code here, or do I need to
modify my viewer.swf to accept the parameter?

Answer 1

A bit more info after some digging around. I've now worked
out how to add AS to the object. I've got this bit of script:
import fl.video.*;
var flvPlayer:FLVPlayback = new FLVPlayback();
addChild(flvPlayer);
flvPlayer.skin = "SkinUnderAllNoCaption.swf"
if(String(loaderInfo.parameters.flaPath) != '')
flvPlayer.source = String(loaderInfo.parameters.flaPath);
else
flvPlayer.source = "water.flv";
I've put this in my HTML:
AC_FL_RunContent(
'codebase', '
http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,0,0',
'width', '550',
'height', '400',
'src', 'Untitled-2',
'quality', 'high',
'pluginspage', '
http://www.macromedia.com/go/getflashplayer',
'align', 'middle',
'play', 'true',
'loop', 'true',
'scale', 'showall',
'wmode', 'window',
'devicefont', 'false',
'id', 'Untitled-2',
'bgcolor', '#ffffff',
'name', 'Untitled-2',
'menu', 'true',
'allowFullScreen', 'false',
'allowScriptAccess','sameDomain',
'movie', 'Untitled-2',
'salign', '',
'flashVars', 'flaPath="fle05115R022.flv"'
); //end AC code
When I load the page, I get the water.flv so it doesn't
appear to be finding the flashVars parm.