Ios 无法播放从Quickblox swift下载的录制音频（.m4a）？

这是我向服务器发送音频的方式：

internal func didFinishRecording(_ recorderViewController: RecorderViewController) {

    let audioFileURL = recorderView.recording.url

    let audioData = try? Data.init(contentsOf: audioFileURL)

    QBRequest.tUploadFile(audioData!, fileName: "recording", contentType: "audio/m4a", isPublic: false, successBlock: {(response: QBResponse!, uploadedBlob: QBCBlob!) in

        QBChat.instance.addDelegate(self)
        let message: QBChatMessage = QBChatMessage()

        let uploadedFileID: UInt = uploadedBlob.id
        let attachment: QBChatAttachment = QBChatAttachment()
        attachment.type = "audio"
        attachment.id = "\(uploadedFileID)"
        message.attachments = [attachment]
        let params : NSMutableDictionary = NSMutableDictionary()
        params["save_to_history"] = true
        message.customParameters = params

        self.dilog?.send(message, completionBlock: {(error: Error?) -> Void in
            self.getMessages()
        })

    }, statusBlock: {(request: QBRequest?, status: QBRequestStatus?) in

        self.uploadProgressView.isHidden = false
        self.uploadProgressView.progress = status!.percentOfCompletion
        if(self.uploadProgressView.progress == 1.0)
        {
            self.uploadProgressView.isHidden = true
        }

    }, errorBlock: {(response: QBResponse!) in

        print(response)
    })
}

这就是我下载音频并将其写入文档目录的方式：

guard let chatItem = self.chatObj else {
        return
    }

    QBRequest.downloadFile(withID: UInt(chatItem.attachments![0].id!)!, successBlock: {(response : QBResponse, audioData: Data) in

        DispatchQueue.main.async {
            do {

                print(audioData)
                let fileManager = FileManager.default
                do {
                    let documentDirectory = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor:nil, create:false)
                    let fileURL = documentDirectory.appendingPathComponent("\(String(describing: chatItem.id!)).m4a")
                    try audioData.write(to: fileURL)

                    try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
                    try AVAudioSession.sharedInstance().setActive(true)
                    self.player = try AVAudioPlayer.init(contentsOf: fileURL)
                    print(self.player)
                    self.player?.prepareToPlay()
                    self.player?.play()

                } catch {
                    print(error)
                }

            } catch {
                print(error)
            }
        }


    }, statusBlock: {(request: QBRequest?, status: QBRequestStatus?) in

        self.uploadProgressView.isHidden = false
        self.uploadProgressView.progress = status!.percentOfCompletion
        if(self.uploadProgressView.progress == 1.0)
        {
            self.uploadProgressView.isHidden = true
        }

    }, errorBlock: {(response :QBResponse) in

        print(response.debugDescription)
    })

和

打印（音频数据）

打印

374694字节

，这意味着存在音频文件

但是当我尝试播放它时，我收到了一条错误消息

错误域=NSOSStatusErrorDomain代码=1685348671“（空）”

我在谷歌上搜索了很多次，但都没用

我正在用lib录音

录制的默认设置为：

let settings: [String: AnyObject] = [
        AVFormatIDKey : NSNumber(value: Int32(kAudioFormatAppleLossless) as Int32),
        AVEncoderAudioQualityKey: AVAudioQuality.max.rawValue as AnyObject,
        AVEncoderBitRateKey: bitRate as AnyObject,
        AVNumberOfChannelsKey: channels as AnyObject,
        AVSampleRateKey: sampleRate as AnyObject
    ]