我正在尝试使用2个AVPlayer实例播放多个音频文件，但是其中一个播放器停下来了不到一秒钟，而不是同时播放所有音频文件。 该程序的逻辑如下：
var player: AVPlayer?将流式传输我数据库中的音频文件。就其本身而言，玩起来很完美。
fileprivate var countPlayer: AVPlayer?播放var player正在播放的当前项目的计数。该计数是一个1到8的序列，对于每个数字，我正在本地存储/处理一个.wav文件，例如1.wav，2.wav ... 8.wav。
当var player的当前时间是某个时间时，将触发countPlayer并播放本地文件1.wav，2.wav..etc中的一个。
问题在于，var countPlayer开始播放时，会导致后台AVPlayer（即var player）停止播放一秒钟，类似于此注释中所述：
Play multiple Audio Files with AVPlayer
var player: AVPlayer? //plays the song
fileprivate var countPlayer: AVPlayer? // plays the count number of song
private func addBoundaryTimeObserver(tableIndexPath: IndexPath) {
let mediaItem = mediaArray[tableIndexPath.row]
guard let url = URL(string: mediaItem.mediaAudioUrlStringRepresentation ?? "") else {return}
let playerItem = AVPlayerItem(url: url)
player = AVPlayer(playerItem: playerItem)
var timesToTransverse = [NSValue]()
//convert string representation of times elements to array
let timesRecorded: [String] = mediaItem.timesRecorded.components(separatedBy: ",")
// Build boundary times from arrayOfBeats keys
let timeDoubles: [Double] = timesRecorded.compactMap {timeString in
if let second = Double("\(timeString)") {
return second
}
return nil
}
guard timeDoubles.count > 0 else {return} //unexpected
timesToTransverse = timeDoubles.map { second in
let cmtime = CMTime(seconds: second, preferredTimescale: CMTimeScale(NSEC_PER_SEC))
return NSValue(time: cmtime)
}
guard timesToTransverse.count != 0 else {return}
guard let playerCell = tableView.cellForRow(at: IndexPath(row: 0, section: 0)) as? PlayerCell else {return}
startTime = Date().timeIntervalSinceReferenceDate
timeIndex = 0
player?.play()
player?.rate = Float(initialPlaybackRate)
// find the index of time
//reset timeObserverToken
// call a function with the new times sorted
// Queue on which to invoke the callback
let mainQueue = DispatchQueue.main
// Add time observer
timeObserverToken =
player?.addBoundaryTimeObserver(forTimes: timesToTransverse, queue: mainQueue) {
[weak self] in
//because there are no time signature changes, we can simply increment timeIndex with + 1 every time `addBoundaryTimeObserver` completion handler is called and subscript timesToTransverse with timeIndex in order to get the subsequent timeInSeconds
guard let strongSelf = self, strongSelf.timeIndex < timesToTransverse.count else {return}
let timeElement = timesToTransverse[strongSelf.timeIndex]
strongSelf.timeInSeconds = CMTimeGetSeconds(timeElement.timeValue)
//show progress in progressView
let duration = CMTimeGetSeconds(playerItem.duration)
let cmtimeSeconds = CMTime(seconds: strongSelf.timeInSeconds, preferredTimescale: CMTimeScale(NSEC_PER_SEC))
//Total time since timer started, in seconds
strongSelf.timeInSeconds = Date().timeIntervalSinceReferenceDate - strongSelf.startTime
let timeString = String(format: "%.2f", strongSelf.timeInSeconds)
strongSelf.timeString = timeString
//use reminder operator to determine the beat count
let beat = (strongSelf.timeIndex + 1) % 8 == 0 ? 8 : ((strongSelf.timeIndex + 1) % 8)
//play the beat count : 1, 2, ...8
self.preapareToPlayAudio(beatCount: beat)
/*
0: (0 + 1) % 8 = 1
1: (1 + 1) % 8 = 2
6: (6 + 1) % 8 = 7
7: (7 + 1) % 8 = 0
*/
strongSelf.timeIndex += 1
}
}//end addBoundaryTimeObserver
//prepare determine what wav file to play
private func preapareToPlayAudio(beatCount: Int) {
switch beatCount {
case 1:
guard let url = Bundle.main.url(forResource: "1", withExtension: "wav") else {return}
playWith(beatCountURL: url)
//7 more cases go here .....
default: print("unexpected case here")
}
}//end play(beatCount: Int)
private func playWith(beatCountURL: URL) {
let playerItem = AVPlayerItem(url: beatCountURL)
countPlayer = AVPlayer(playerItem: playerItem)
countPlayer?.play()
}
答案 0 :(得分：1)
使用AVAudioPlayerNode，AVAudioMixerNode，AVAudioEngine会更好。使用这些类，您将不会像现在那样遇到问题。设置起来也不难。
您可以查看要点，为了在Playgrounds中播放声音，您需要将音频文件放入Project Navigator中的Resources文件夹中： https://gist.github.com/standinga/24342d23acfe70dc08cbcc994895f32b
当触发顶部声音时，该代码不会停止背景音频。
这里也是相同的代码：
import AVFoundation
import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true
class AudioPlayer {
var backgroundAudioFile:AVAudioFile
var topAudioFiles: [AVAudioFile] = []
var engine:AVAudioEngine
var backgroundAudioNode: AVAudioPlayerNode
var topAudioAudioNodes = [AVAudioPlayerNode]()
var mixer: AVAudioMixerNode
var timer: Timer!
var urls: [URL] = []
init (_ url: URL, urls: [URL] = []) {
backgroundAudioFile = try! AVAudioFile(forReading: url)
topAudioFiles = urls.map { try! AVAudioFile(forReading: $0) }
engine = AVAudioEngine()
mixer = AVAudioMixerNode()
engine.attach(mixer)
engine.connect(mixer, to: engine.outputNode, format: nil)
self.urls = urls
backgroundAudioNode = AVAudioPlayerNode()
for _ in topAudioFiles {
topAudioAudioNodes += [AVAudioPlayerNode()]
}
}
func start() {
engine.attach(backgroundAudioNode)
engine.connect(backgroundAudioNode, to: mixer, format: nil)
backgroundAudioNode.scheduleFile(backgroundAudioFile, at: nil, completionHandler: nil)
try! engine.start()
backgroundAudioNode.play()
for node in topAudioAudioNodes {
engine.attach(node)
engine.connect(node, to: mixer, format: nil)
try! engine.start()
}
// simulate rescheduling files played on top of background audio
DispatchQueue.global().async { [unowned self] in
for i in 0..<1000 {
sleep(2)
let index = i % self.topAudioAudioNodes.count
let node = self.topAudioAudioNodes[index]
node.scheduleFile(self.topAudioFiles[index], at: nil, completionHandler: nil)
node.play()
}
}
}
}
let bundle = Bundle.main
let beepLow = bundle.url(forResource: "beeplow", withExtension: "wav")!
let beepMid = bundle.url(forResource: "beepmid", withExtension: "wav")!
let backgroundAudio = bundle.url(forResource: "backgroundAudio", withExtension: "wav")!
let audioPlayer = AudioPlayer(backgroundAudio, urls: [beepLow, beepMid])
audioPlayer.start()