Keynote

If I understand this correctly, you want to have a picture in picture of a live video from a camera shown using a Keynote presentation.

This can't be done from within Keynote, but a workaround is to connect a video camera, webcam, built in iSight camera, iPhone or iPad to the Mac, and swap between Keynote and Quicktime using command and tab keys on the keyboard.

1. Connect your camera to the Mac.
2. Open the QuickTime Player app  on your Mac.
3. Choose File > New Movie Recording.
4. Click the Options pop-up menu, then choose any of the following recording options:

• • Camera: Choose your connected iPhone, iPad or iPod touch.
  • Microphone: Choose a microphone (if you have more than one available).
  • Quality: Choose the recording quality. Maximum-quality recordings produce uncompressed files, which can use large amounts of storage space.