如何用AVAudioPCMBuffer播放声音 [英] how to play sound with AVAudioPCMBuffer

问题描述

我无法用AVAudioPCMBuffer播放声音（尽管我可以使用AVAudioFile）。
我收到了这个错误。

I Cannot play sound with AVAudioPCMBuffer (though I could play with AVAudioFile). I got this error.

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

ERROR: AVAudioBuffer.mm:169: -[AVAudioPCMBuffer initWithPCMFormat:frameCapacity:]: required condition is false: isCommonFormat

这是我下面的代码，我非常感谢你的帮助。

here is my code below, and I'd really appreciate for your help.

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.
}

}

推荐答案

让我分享一下，虽然我不完全理解，但这种方法仍有效。

just let me share, this worked somehow, though I don't understand fully.

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.
}

}

这篇关于如何用AVAudioPCMBuffer播放声音的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！