我想构建一个iOS应用程序(使用Swift 3和Xcode 8.2.1),该应用程序从iPhone的麦克风进行记录并将记录保存到.caf
文件中。
首先,我在项目的Info.plist文件中添加了以下几行:
<key>NSMicrophoneUsageDescription</key>
<string>Some description to explain why access is required</string>
然后,我创建了一个简单的
UIViewController
,它设置了AVAudioEngine
并在点击Record
和Stop
按钮时安装/删除了音频接头。ViewController.swift
import UIKit
import AVFoundation
class ViewController: UIViewController {
var engine = AVAudioEngine()
var file: AVAudioFile?
var player = AVAudioPlayerNode()
override func viewDidLoad() {
super.viewDidLoad()
guard let url = urlFor(filename: "test.caf") else { return }
do {
file = try AVAudioFile(forWriting: url, settings: engine.inputNode!.inputFormat(forBus: 0).settings, commonFormat: engine.inputNode!.inputFormat(forBus: 0).commonFormat, interleaved: false)
} catch {
print("Error: \(error)")
}
engine.attach(player)
engine.connect(player, to: engine.mainMixerNode, format: engine.mainMixerNode.outputFormat(forBus: 0))
do {
try engine.start()
} catch {
print("Error: \(error)")
}
}
@IBAction func record(sender: AnyObject) {
engine.inputNode?.installTap(onBus: 0, bufferSize: 1024, format: engine.mainMixerNode.outputFormat(forBus: 0)) { (buffer, time) -> Void in
do {
try self.file?.write(from: buffer)
} catch {
print("Error: \(error)")
}
}
}
@IBAction func stop(sender: AnyObject) {
engine.inputNode?.removeTap(onBus: 0)
// Print the url of the saved file
let urls = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)
print(urls[urls.endIndex - 1])
}
func urlFor(filename: String) -> URL? {
// Get url of saved file
if let dir = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.allDomainsMask, true).first {
let path = dir.appending(filename)
return URL(fileURLWithPath: path)
}
return nil
}
}
该应用程序可以在模拟器上正常运行:我可以记录我的声音,获取记录文件的网址,并测试我的声音是否已正确记录。但是,该应用程序会在我在设备上启动后立即崩溃(在iOS 10.2.1上使用iPhone 6s测试)。控制台为我提供了以下日志:
2017-02-08 17:09:14.330151 AudioEngineSimpleApp[7100:2659416] Audio files cannot be non-interleaved. Ignoring setting AVLinearPCMIsNonInterleaved YES.
2017-02-08 17:09:14.333715 AudioEngineSimpleApp[7100:2659416] [central] 54: ERROR: [0x1b7440c40] >avae> AVAudioFile.mm:160: AVAudioFileImpl: error -54
2017-02-08 17:09:14.333796 AudioEngineSimpleApp[7100:2659416] [central] 54: ERROR: [0x1b7440c40] >avae> AVAudioFile.mm:122: ReadMagicCookie: error -50
2017-02-08 17:09:14.334369 AudioEngineSimpleApp[7100:2659416] *** Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio', reason: 'error -50'
这个问题似乎与堆栈溢出线程AVAudioPlayer working on Simulator but not on Real Device有关,但是我无法弄清楚如何将其响应实现到我自己的代码中以解决我的问题。
最佳答案
我已经重构了代码,并使用以下urlFor(filename: String) -> URL?
属性替换了旧的url
方法:
let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("test.caf")
因此,以下代码可在设备上正常运行:
import UIKit
import AVFoundation
class ViewController: UIViewController {
@IBOutlet weak var recordButton: UIButton!
let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("test.caf")
//let url = URL(fileURLWithPath: NSTemporaryDirectory().appending("test.caf")) also works
var engine = AVAudioEngine()
override func viewDidLoad() {
super.viewDidLoad()
recordButton.setTitle("Record", for: .normal)
let file: AVAudioFile
do {
file = try AVAudioFile(forWriting: url, settings: engine.inputNode!.outputFormat(forBus: 0).settings)
} catch {
print("Error: \(error)")
return
}
engine.inputNode?.installTap(onBus: 0, bufferSize: 1024, format: engine.inputNode!.outputFormat(forBus: 0)) { (buffer, time) -> Void in
do {
try file.write(from: buffer)
} catch {
print("Error: \(error)")
}
}
}
@IBAction func toggleAction(_ sender: AnyObject) {
engine.isRunning ? stopRecording() : startRecording()
}
func startRecording() {
do {
// Start engine
try engine.start()
// Toggle button title
recordButton.setTitle("Stop", for: .normal)
} catch {
print("Error: \(error)")
}
}
func stopRecording() {
// Stop engine
engine.stop()
// Toggle button title
recordButton.setTitle("Record", for: .normal)
print(url)
}
}
关于ios - AVAudioFile初始化可在模拟器上运行,但在设备上崩溃,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/42118181/