Programming iOS 6, 3rd Edition

Introduction to AV Foundation Video

A large suite of AV Foundation classes provides detailed access to media components. To access AV Foundation, you’ll need to link to AVFoundation.framework (and probably CoreMedia.framework as well), and import <AVFoundation/AVFoundation.h>. For a list of classes, see the AV Foundation Framework Reference. AV Foundation is a huge topic, so there isn’t space here to do more than introduce the concepts involved.

The AV Foundation class that performs actual playing of media is AVPlayer. An AVPlayer has an AVPlayerItem; this is its media. An AVPlayerItem comprises tracks (AVPlayerItemTrack), which can be individually enabled or disabled. It gets these from its underlying AVAsset; this is the basic media unit, as it were, providing you with access to actual tracks (AVAssetTrack) and metadata. As with an MPMoviePlayerController, you might use an AVPlayer to play a pure sound rather than a full-fledged movie.

An AVPlayer can be an AVQueuePlayer, a subclass that allows multiple AVPlayerItems to be loaded up and then played in sequence; I’ll give an example in Chapter 29 of using an AVQueuePlayer to play a series of songs. AVQueuePlayer also has an advanceToNextItem method, and its list of items can be changed dynamically, so you could use it to give the user access to a set of “chapters.”

To display an AVPlayer’s movie, you need an AVPlayerLayer (a CALayer subclass). You are unlikely to take this approach unless you need the extended powers of AV Foundation ...