我想构建一个iOS应用程序(使用Swift 3和Xcode 8.2.1),它可以从iPhone的麦克风中录音,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
,它设置了一个AVAudioEngine
,并在点击Record
和Stop
按钮时安装/删除音频抽头。
- 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
}
}
该应用程序在模拟器上运行良好:我可以录制我的声音,获取录制文件的url并测试我的声音是否已正确录制。然而,当我在设备上启动该应用程序时,它就会崩溃(在iOS 10.2.1上用iPhone 6s测试)。控制台提供以下日志:
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Stack Overflow线程AVAudioPlayer working on Simulator but not on Real Device有关,但我不知道如何将其响应实现到我自己的代码中以解决我的问题。
2条答案
按热度按时间xzv2uavs1#
我已经重构了我的代码,并将旧的
urlFor(filename: String) -> URL?
方法替换为以下url
属性:因此,以下代码在设备上正常工作:
093gszye2#
如果有人需要在App沙盒Documents文件夹外读取
AVAudioFile
(例如从UIDocumentPickerViewController
或SwiftUI的.fileImporter{}
接收文件的URL
)。然后在访问文件应用程序之前需要调用url.startAccessingSecurityScopedResource()
。处理输入后,调用url.stopAccessingSecurityScopedResource()
更多信息:Apple Documentation