From Vitamin D:
Vitamin D Video detects people and moving objects in video streams for security and monitoring purposes. You can take hours of video and choose to see only specific types of clips. For example, you can create "rules" to show only clips of people walking through a door, or moving objects crossing a line, or people lingering on top of a lawn. In addition, you can choose to be notified by email or a sound alert when those rules are triggered in the future.