ios - avplayer播放视频时没有声音

Question

这是我播放 mp4 的所有代码，mp4 正在播放但没有声音

import UIKit

import AVFoundation
class ViewController: UIViewController {

@IBOutlet weak var containerView: UIView!

var playerLayer:AVPlayerLayer!
var player:AVPlayer!
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    let path = NSBundle.mainBundle().pathForResource("huoguo", ofType: "mp4")
    let url = NSURL(fileURLWithPath: path!)
    let asset = AVAsset(URL: url)
    let playerItem = AVPlayerItem(asset: asset)
    self.player = AVPlayer(playerItem: playerItem)
    self.playerLayer = AVPlayerLayer(player: player)
    self.playerLayer.frame = CGRectMake(0, 0, UIScreen.mainScreen().bounds.width, UIScreen.mainScreen().bounds.width * 9 / 16)
    self.containerView.layer.addSublayer(playerLayer)
    //self.playerLayer.player?.volume = 1
    self.playerLayer.player?.play()
}
}

我确定它有声音，因为我在使用 VLC 播放 mp4 时可以听到，我是不是错过了什么？

Answer 1

检查您的手机是否处于静音模式。如果它是无声的，请尝试将下面的代码添加到 viewDidLoad:

swift 2.3

try! AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, withOptions: [])

swift 3

try! AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, with: [])

swift 4.2

try! AVAudioSession.sharedInstance().setCategory(.playback, options: [])

或者只是

try! AVAudioSession.sharedInstance().setCategory(.playback)