Actually, you are talking about something completely different. Motion tracking is quite different than Camera tracking, and you do not need 2 cameras for either, although some motion trackers use multiple camera systems.
The markers reference you made is how some motion capture software works, but there are many different ways to do this.
As for the camera tracking, which is what I was talking about,... you may or may not need trackers, depending on your scene, and you definately only need one camera, whether it's a cheap hand held, or an expensive HD or film camera. The only shots I've ever had to use markers on, was one on a soccer field since the grass did not have any trackable features. The other was a field of tall grass and trees on a windy day,... everything was moving so bad there was nothing stable to track, so we put tennis balls on poles and touched them out later.
The markers reference you made is how some motion capture software works, but there are many different ways to do this.
As for the camera tracking, which is what I was talking about,... you may or may not need trackers, depending on your scene, and you definately only need one camera, whether it's a cheap hand held, or an expensive HD or film camera. The only shots I've ever had to use markers on, was one on a soccer field since the grass did not have any trackable features. The other was a field of tall grass and trees on a windy day,... everything was moving so bad there was nothing stable to track, so we put tennis balls on poles and touched them out later.