1) Select the area you want to overlay, be it the whole video or just a small area.
2) Prep your clips, ensure it matches the frame width/height of your video. You can use Rehan's Cropping effects, DPL 110% by Patrick or Blaine's zooms. Any method will do as long as it matches. Ensure you have the desired effects on your clip too eg Hue, Cycles entire colour spectrum.
3) Find the section you want to overlay. If you are overlaying the whole video please skip to step 8.
4) Cut the clip IN THE MIDDLE OF THE SECTION!!!! Or as near as possible, then slide the clips over so they fade. You can adjust this as much as you need to get the appropriate timing...just drag the clip further one way and then slide the other half of your video the rest of the way!
5) You will now need to download Blaine's translucency package, you can find it on his website and on the movie maker forums
6) Trial and error with different translucency strengths until you find on that works well for you. SOmetimes it can be better to use compAaddB (another blaine effect) if using short overlays like lightning or fireworks, for example.
7) Once you've found your correct consistency you're done!
- 8 ) You will have to essentially sandwich you entire video. If it is one colour wash, stretch out the wash so it matches the length of the video, cut it in half and place the front half to the very start of the timeline, then drag your video over it. You can then drag the other half of the picture over the video, to "sndwich". For moving overlays, you will have to do this for each individual section, making sure at all times you can see both video and overlay. This is a little time consuming but very much worth it. Okay, now skip back to step 4 and this may help to clear things up.
A little hard to explain in text! But I hope everyone understands!