錄制視頻/音頻時播放系統聲音

Question

當我開始錄制視頻時，我正試圖播放蘋果要求的“嘟嘟”聲。 我發現通過SO和其他來源，當你的音頻輸入沒有一些配置時，你無法播放聲音。

這是我對配置方法的嘗試：

private void SetupAudio()
    {
        beepSound = AssetBank.GetSystemSoundWav("video_record", "video_beep");
        AudioSession.Initialize();
        AudioSession.Interrupted += delegate
        {
            Console.WriteLine("Interrupted handler");
        };

        AudioSession.Category = AudioSessionCategory.PlayAndRecord;
        AudioSession.OverrideCategoryMixWithOthers = true;

        NSError err;
        AVAudioSession.SharedInstance().SetActive(true, out err);
    }

這是我設置錄制會話的代碼：

public void SetupVideoCaptureSession(AVCaptureDevicePosition position)
    {

        // Setup devices
        foreach (var device in AVCaptureDevice.Devices)
        {
            if (device.HasMediaType(AVMediaType.Video))
            {
                if (device.Position == AVCaptureDevicePosition.Front)
                {
                    frontCam = device;
                } else if (device.Position == AVCaptureDevicePosition.Back)
                {
                    backCam = device;
                }
            }
        }

        // Create capture session
        captureSession = new AVCaptureSession();
        captureSession.BeginConfiguration();
        captureSession.SessionPreset = AVCaptureSession.Preset640x480;
        // Create capture device

        switch (position)
        {
            case AVCaptureDevicePosition.Back:
                videoDevice = backCam;
                break;

            case AVCaptureDevicePosition.Front:
                videoDevice = frontCam;
                break;
        }

        if (null == videoDevice)
        {
            using (var alert = new UIAlertView { Message = "No camera detected!" })
            {
                alert.AddButton("Okay!");
                alert.Show();
            }
            return;
        }

        audioDevice = AVCaptureDevice.DefaultDeviceWithMediaType(AVMediaType.Audio);

        // Create capture device input
        NSError videoError, audioError;
        videoDeviceInput = new AVCaptureDeviceInput(videoDevice, out videoError);
        audioDeviceInput = new AVCaptureDeviceInput(audioDevice, out audioError);

        captureSession.AddInput(videoDeviceInput);
        captureSession.AddInput(audioDeviceInput);

        // Create capture device output
        videoOutput = new AVCaptureMovieFileOutput();
        videoOutput.MaxRecordedDuration = new CMTime(10, 1);

        captureSession.AddOutput(videoOutput);

        if (null != previewLayer)
            previewLayer.RemoveFromSuperLayer();

        // Create preview layer
        previewLayer = AVCaptureVideoPreviewLayer.FromSession(captureSession);
        previewLayer.Orientation = AVCaptureVideoOrientation.Portrait;
        previewLayer.VideoGravity = "AVLayerVideoGravityResizeAspectFill";
        previewLayer.Frame = new RectangleF(new PointF(), ScreenSize);

        this.ParentScrollView.Layer.InsertSublayer(previewLayer, 0);

        // Start capture session

        SetupAudio();
        captureSession.CommitConfiguration();
        captureSession.StartRunning();
    }

無論我嘗試什么，在我開始捕捉會話后，我都無法發出聲音。 有人在MonoTouch中解決了這個問題嗎？

Answer 1

這就是我在The Harlem Shake中使用的內容 ：

AudioSession.Initialize();
AudioSession.Category = AudioSessionCategory.MediaPlayback;
AudioSession.OverrideCategoryMixWithOthers = true;

然后把它關掉，我這樣做：

AudioSession.Initialize();
AudioSession.Category = AudioSessionCategory.AmbientSound;
AudioSession.OverrideCategoryMixWithOthers = false;

這允許我在視頻捕捉期間與AVAudioPlayer一起玩“Harlem Shake”。 它還會覆蓋iDevice上的靜音開關。 我不知道兩個部分是否需要AudioSession.Initialize() ，你可能只需要調用一次。

Answer 2

昨天整天把頭發拉了出來后，我開始工作了。

private void PlayBeepSound()
    {
        NSError err;
        var player = AVAudioPlayer.FromUrl(NSUrl
            .FromFilename("Sounds/video_record/video_beep.wav"), out err);
        player.Play();
    }

以前，我試圖使用sound.PlaySystemSound（），但是沒有用。 切換到AVAudioPlayer允許播放聲音。 至少我學到了很多關於iPhone音頻內部的知識！

Answer 3

嗨其他開發人員在這里是針對上述問題的Objective C代碼，

@property (strong, nonatomic) AVAudioPlayer *audioPlayer;

NSURL *soundUrl = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"VoicemailSound" ofType:@"mp3"]]; //Download and add a system sound to your project and mention its name and type here
self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:soundUrl error:nil];

[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionDefaultToSpeaker|AVAudioSessionCategoryOptionMixWithOthers error: nil];

[self.audioPlayer prepareToPlay];
[self.audioPlayer play];