What is the best way to start a movie the first time your app starts

I want to have a movie start the first time my app is launched to train users on its use, say a 50 second clip.

How would I go about doing this in an iPad app?

(I am building a very complex platform that has hooks into the web and need users to be aware of that. The video will explain that users can go to the web开发者_高级运维site for different features. When the app starts for the FIRST TIME only I want the video to play.)

Don't force users to sit thru a 50 second movie when the app starts. Your user interface should be obvious enough that they can figure out the basics without watching a training video. If you want to offer it, provide a help button, where they can watch it when they choose to.

See the iPhone HIG section Minimal User Help, which says:

A hallmark of the design of iPhone OS–based devices is ease of use, so it’s crucial that you meet users’ expectations and make the use of your application immediately obvious.

EDIT -- The simplest way to keep track would be to store a flag indicating whether or not you have shown the video by using NSUserDefaults. Check if it's set at startup, set it after showing the video the first time.