yeralin / cachingplayeritem

Play and cache media content simultaneously on your iOS device

CachingPlayerItem

Stream and cache media content on your iOS device

CachingPlayerItem is a subclass of AVPlayerItem. It allows you to play and cache media files. You can start to play a remote file immediately, without waiting the file to be downloaded completely. Once it is downloaded, you will be given an opportunity to store it for future use. You can play NSData objects also.

Features

• Written in Swift 2.2
• Convenient notifications through a delegate mechanism
• Both local and remote files are supported. You can play NSData objects straight from the memory.
• CachingPlayerItem is a subclass of AVPlayerItem, but with a custom loader. So you still have the power of AVFoundation Framework

Adding to your project

Simply add CachingPlayerItem.swift to your project

Usage

Get a url to file you want to play:

let songURL = NSURL(string: "https://example.com/audio.mp3")!

Instantiate CachingPlayerItem:

let playerItem = CachingPlayerItem(url: songURL)

Alternatively, you may want to play from NSData object. In this case, use the following CachingPlayerItem initializer:

init(data: NSData, mimeType: String, fileExtension: String)

for mp3 files, the mimeType is "audio/mpeg". For other types, use google.

Instantiate player with the playerItem:

player = AVPlayer(playerItem: playerItem)

Play it:

player.play()

Note, that you need to keep a strong reference to your player.

If you want to cache a file without playing it, or to preload it for future playing, use download() method:

playerItem = CachingPlayerItem(url: songURL)
playerItem.download()

It's fine to start playing the item while it's downloading.

So, minimal code required to play a remote audio looks like this:

import UIKit
import AVFoundation

class ViewController: UIViewController {

	var player: AVPlayer!

	override func viewDidLoad() {

		super.viewDidLoad()

		let songURL = NSURL(string: "https://example.com/audio.mp3")!
		let playerItem = CachingPlayerItem(url: songURL)
		player = AVPlayer(playerItem: playerItem)
		player.play()

	}

}

CachingPlayerItemDelegate protocol

Usually, you want to conform to the CachingPlayerItemDelegate protocol. It gives you 4 handy methods to implement:

// called when file is fully dowloaded
optional func playerItem(playerItem: CachingPlayerItem, didFinishDownloadingData data: NSData)
    
// called every time new portion of data is received
optional func playerItem(playerItem: CachingPlayerItem, didDownloadBytesSoFar bytesDownloaded: Int, outOf bytesExpected: Int)
    
// called after prebuffering is finished, so player item is ready to play. Called only once, after initial prebuffering
optional func playerItemReadyToPlay(playerItem: CachingPlayerItem)
    
// called when some media did not arrive in time to continue playback
optional func playerItemDidStopPlayback(playerItem: CachingPlayerItem)

Don't forget to set delegate property of the playerItem to self. Notice, that all 4 methods are optional.

Demo

import UIKit
import AVFoundation

class ViewController: UIViewController, CachingPlayerItemDelegate {

    var player: AVPlayer!
   
    override func viewDidLoad() {
        super.viewDidLoad()

        let songURL = NSURL(string: "https://example.com/audio.mp3")!
        let playerItem = CachingPlayerItem(url: songURL)
        playerItem.delegate = self        
        player = AVPlayer(playerItem: playerItem)
    }
    
    func playerItemDidStopPlayback(playerItem: CachingPlayerItem) {
        print("Not enough data for playback. Probably because of the poor network. Wait a bit and try to play later.")
    }
    
    func playerItemReadyToPlay(playerItem: CachingPlayerItem) {
        player.play()
    }
    
    func playerItem(playerItem: CachingPlayerItem, didFinishDownoadingData data: NSData) {
        print("File is downloaded and ready for storing")
    }
    
    func playerItem(playerItem: CachingPlayerItem, didDownloadBytesSoFar bytesDownloaded: Int, outOf bytesExpected: Int) {
        print("Loaded so far: \(bytesDownloaded) out of \(bytesExpected)")
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

Known limitations

• CachingPlayerItem loads its content sequentially. If you seek to yet not downloaded portion, it waits until data previous to this position is downloaded, and only then starts playback.
• Downloaded data is stored completely in RAM, therefore you're restricted by device's memory. Despite CachingPlayerItem is very handy for relatively small audio files (up to 100MB), you may have memory-related problems with large video files.