While processing my first Game On! video I came across a bit of an issue.  I had rendered a lower 3rd banner in After Effects and wanted to import it as a layer into Sony Vegas which I use to do the final processing of my videos.  The problem was when I imported the video, it usually imported with a black background.

I had done a search for this in Google and surprisingly found very little in ways of importing transparent videos, all I could find was how to import transparent backgrounds (usually involving a PNG file).  I did how ever find one saving grace, one of the youtube videos explained exactly how to do it. Trollshopping published a video entitled Tutorial: How to render transparent clips in After Effects & the tricky ìmport in Sony Vegas

In the comments they state what needs to be done (I reformatted it to make the steps more clear):

In After Effects

  1. Have your Transparency Toogle Grid in transparent mode enabled
  2. Add composition to render queue
  3. Go to lossless-option
    • Go with a format supporting alpha-channels (like AVI)
    • Set RGB to RGB+ALPHA in the channel option!
    • Press OK
  4. Render


Note: The size of the video is going to be quite large and take a while to render as it is rendering both RGB and Alpha at the same time. My export was only a few seconds long but took 5 minutes to render and was over 1GB in size.

In Sony Vegas

  1. Import your clip rendered in After Effects into Vegas like you import every other file
  2. Drop your clip on the timeline. it will not be transparent.
  3. Right Click on it
    • go to Properties
    • Select the Media tab
    • Change the AlphaChannel option from Undefined to PreMultiplied.


Note: Because the file size is very large for your transparency, preview may be jittery and rendering will take a bit longer to process, however the output is amazing.

Hope this helps people find the answer quicker as this does not seem to be a very popular question on the net.