So there are probably easier ways to do this but I will risk laughter and teasing to try and help out with a very basic example!
open up after effects and edit the video to your liking, add effects or change the speed, etc. I saw some cool ones that had some time remapping done to them, a tv screen type filter on it, etc.
This is a banner I made for something, just pretend its a video =x
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After your video is edited and saved to a proper video format, open up adobe media encoder. Drag the file into the app and save it as an flv. Here is an example I chose, matching sources properties as an flv file.
Edit: you can encode for flv using after effects, I personally prefer saving it as a video in ae and converting using this tool.
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Now, go into flash and open up the component inspector.
double click or drag and drop the flv playback component (comes with flash) to bring it into your canvas in flash.
Make sure it is selected and open up the properties tab.
Click on content path and find your flv file, make sure its in the same place you plan to store it on the server. Click on skin and choose none so there is no playback ui in your way.
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click off of the component and click properties, on size, hit edit > match contents to make the flash movie the same size as the imported video.
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