When you add a video from Google Drive by Insert>>Drive>>Videos there is no autoplay option.
Here is a way to make then auto start if you want to do that.
- I uploaded my mp4 file to a public dropbox folder See Using Dropbox
- I right clicked on it and captured its public URL
- In the web page Insert>>More gadgets
- Search for "iframe include" and insert the gadget
- Configure it with the URL from step 2
- I set width to 600 and height to 380 but use what is appropriate for your video
- Save everything
Unfortunately Dropbox has notified me: "Your Dropbox public links have been suspended".
Apparently there was too much bandwidth for their service. Maybe a paid version would help.
It's too bad we can't use Google Drive in this way.
The service has been restored. We'll see how long it lasts.