9

我不能用 AVAudioPCMBuffer 播放声音（虽然我可以用 AVAudioFile 播放）。我得到了这个错误。

错误：AVAudioBuffer.mm:169：-[AVAudioPCMBuffer initWithPCMFormat:frameCapacity:]：所需条件为假：isCommonFormat

下面是我的代码，非常感谢您的帮助。

import UIKit
import AVFoundation

class ViewController: UIViewController {

let audioEngine: AVAudioEngine = AVAudioEngine()
let audioFilePlayer: AVAudioPlayerNode = AVAudioPlayerNode()

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    audioEngine.attachNode(audioFilePlayer)

    let filePath: String = NSBundle.mainBundle().pathForResource("test", ofType: "mp3")!
    let fileURL: NSURL = NSURL(fileURLWithPath: filePath)!
    let audioFile = AVAudioFile(forReading: fileURL, error: nil)
    let audioFormat = audioFile.fileFormat
    let audioFrameCount = UInt32(audioFile.length)
    let audioFileBuffer = AVAudioPCMBuffer(PCMFormat: audioFormat, frameCapacity: audioFrameCount)

    var mainMixer = audioEngine.mainMixerNode
    audioEngine.connect(audioFilePlayer, to:mainMixer, format: audioFileBuffer.format)

    audioFilePlayer.scheduleBuffer(audioFileBuffer, atTime: nil, options: nil, completionHandler: nil)

    var engineError: NSError?
    audioEngine.startAndReturnError(&engineError)

    audioFilePlayer.play()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}
4

5 回答 5

8

让我分享一下，这以某种方式起作用，尽管我不完全理解。

import UIKit
import AVFoundation

class ViewController: UIViewController {

var audioEngine: AVAudioEngine = AVAudioEngine()
var audioFilePlayer: AVAudioPlayerNode = AVAudioPlayerNode()

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.


    let filePath: String = NSBundle.mainBundle().pathForResource("test", ofType: "mp3")!
    println("\(filePath)")
    let fileURL: NSURL = NSURL(fileURLWithPath: filePath)!
    let audioFile = AVAudioFile(forReading: fileURL, error: nil)
    let audioFormat = audioFile.processingFormat
    let audioFrameCount = UInt32(audioFile.length)
    let audioFileBuffer = AVAudioPCMBuffer(PCMFormat: audioFormat, frameCapacity: audioFrameCount)
    audioFile.readIntoBuffer(audioFileBuffer, error: nil)

    var mainMixer = audioEngine.mainMixerNode
    audioEngine.attachNode(audioFilePlayer)
    audioEngine.connect(audioFilePlayer, to:mainMixer, format: audioFileBuffer.format)
    audioEngine.startAndReturnError(nil)

    audioFilePlayer.play()
    audioFilePlayer.scheduleBuffer(audioFileBuffer, atTime: nil, options: nil, completionHandler: nil)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

}
于 2014-11-01T03:35:30.197 回答
3

问题是您将 PCM 缓冲区的格式设置为非 PCM 格式。因此，您需要AVAudioPCMBuffer使用 AVAudioFile 的processingFormat.

于 2014-11-04T01:12:35.407 回答
3

使用时，AVAudioPCMBuffer()如果您尝试使用不是mixer.outputFormat(forBus: 0)

它不会接受单声道格式，它会抱怨混音器的输出格式和您的格式之间的不匹配，即使您描述的格式完全相同，也不会产生解释问题所在的错误。

于 2019-08-10T23:42:13.933 回答
0

将@Bick 的代码更新为Swift 5.3

代码逻辑很容易搞定

  • 首先，准备数据

创建一个空的AVAudioPCMBuffer，然后在其中填充音频数据。

  • 其次，连接节点，用数据玩

    import UIKit
import AVFoundation

  class ViewControllerX: UIViewController {

    var audioEngine = AVAudioEngine()
    var audioFilePlayer = AVAudioPlayerNode()

    override func viewDidLoad() {
      super.viewDidLoad()

      // prepare the data
      guard let filePath = Bundle.main.path(forResource: "test", ofType: "mp3") else{ return }

      print("\(filePath)")
      let fileURL = URL(fileURLWithPath: filePath)
      do {
          let audioFile = try AVAudioFile(forReading: fileURL)

          let audioFormat = audioFile.processingFormat
          let audioFrameCount = UInt32(audioFile.length)
          guard let audioFileBuffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: audioFrameCount) else{ return }
          try audioFile.read(into: audioFileBuffer)

          // connect the nodes, and use the data to play
          let mainMixer = audioEngine.mainMixerNode
          audioEngine.attach(audioFilePlayer)
          audioEngine.connect(audioFilePlayer, to: mainMixer, format: audioFileBuffer.format)

          try audioEngine.start()

          audioFilePlayer.play()
          audioFilePlayer.scheduleBuffer(audioFileBuffer, completionHandler: nil)

      } catch {
          print(error)
      }

    }
}
于 2020-12-02T03:24:22.350 回答
0

您应该使用 audioFile.processingFormat 作为 AVAudioPCMBuffer 构造函数的参数，而不是调用 audioFile.fileFormat。

let buffer = AVAudioPCMBuffer(pcmFormat: audioFile.processingFormat,
                                            frameCapacity: bufferCapacity)
于 2021-01-27T05:18:34.577 回答