Question

如何以编程方式禁用相机快门声，当我拍照时总是发出声音，我正在调用MediaCapture的Dispose方法来发出声音。有没有办法禁用那个声音？

以下是初始化代码：

  private async Task InitializeQrCode(CaptureElement captureElement)
    {
        string error = null;
        try
        {
            if (mediaCapture == null)
            {
                mediaCapture = new MediaCapture();

                var _deviceInformation = await GetCameraDeviceInfoAsync(Windows.Devices.Enumeration.Panel.Back);

                var settings = new MediaCaptureInitializationSettings();
                settings.StreamingCaptureMode = StreamingCaptureMode.Video;
                settings.PhotoCaptureSource = PhotoCaptureSource.VideoPreview;
                settings.AudioDeviceId = "";
                if (_deviceInformation != null)
                    settings.VideoDeviceId = _deviceInformation.Id;

                await mediaCapture.InitializeAsync(settings);

                var maxResolution = mediaCapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.Photo).Aggregate((i1, i2) => (i1 as VideoEncodingProperties).Width > (i2 as VideoEncodingProperties).Width ? i1 : i2);
                await mediaCapture.VideoDeviceController.SetMediaStreamPropertiesAsync(MediaStreamType.Photo, maxResolution);

                if (mediaCapture.VideoDeviceController.FocusControl.FocusChangedSupported)
                {
                    var focusSettings = new FocusSettings();
                    focusSettings.AutoFocusRange = AutoFocusRange.FullRange;
                    focusSettings.Mode = FocusMode.Auto;
                    focusSettings.WaitForFocus = true;
                    focusSettings.DisableDriverFallback = false;

                    mediaCapture.VideoDeviceController.FocusControl.Configure(focusSettings);
                }

                await mediaCapture.VideoDeviceController.ExposureControl.SetAutoAsync(true);

                mediaCapture.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
                mediaCapture.SetRecordRotation(VideoRotation.Clockwise90Degrees);
            }

            captureElement.Source = mediaCapture;
            await mediaCapture.StartPreviewAsync();
        }
        catch (Exception ex)
        {
            DialogBox.ShowOkMessage(this, "Error:" + ex.Message);
        }
    }

这里是用于捕捉图像的代码，在CapturePhotoToStreamAsync上播放快门声音：

 var stream = new InMemoryRandomAccessStream();
            await mediaCapture.CapturePhotoToStreamAsync(imgProp, stream);


            stream.Seek(0);
            var wbm = new WriteableBitmap(WPAppConstants.Dimension.ImageEncodingWidth, WPAppConstants.Dimension.ImageEncodingHeight);
            await wbm.SetSourceAsync(stream);
            var result = bcReader.Decode(wbm);


            if (result != null)
            {
                var torch = mediaCapture.VideoDeviceController.TorchControl;
                if (torch.Supported) torch.Enabled = false;
                await StopQrCodeScan();

                var resultEvent = Result;
                if (resultEvent != null)
                {
                    resultEvent(null, new CameraClickedEventArgs { EncodedData = result.Text });
                }
            }

演示项目Onedrive Link

Answer 1

你提出的问题是：

如何在不播放快门声的情况下处理MediaCapture

答案就是打电话（假设你正在运行预览，因为你在拍摄时几乎总是会运行它）：

await mediaCapture.StopPreviewAsync();
captureElement.Source = null;
mediaCapture.Dispose();

执行该代码不会播放快门声。作为参考，请参阅UWP CameraStarterKit SDK sample，它仅在捕捉开始或停止时播放快门声。

话虽如此，我注意到你的问题中存在一些矛盾，你说：

拍照时总是发出声音，我叫Dispose 发出声音的MediaCapture的方法

暗示捕获和处置都会触发声音。您可能会对这些概念感到有些困惑。 Dispose method of the MediaCapture释放非托管资源。调用Dispose不会自动触发快门声音，它与您拍摄照片或捕捉视频时可能听到的快门声音无关。当您调用CapturePhotoToStorageFileAsync或StartRecordToStorageFileAsync等方法来通知用户（及其周围的人）相机处于活动状态时，会播放声音。

我不知道如何为您的应用专门禁用快门声音。你有什么想做的事需要静音捕捉吗？

PS：这有点偏离主题，但是您发布了比重现快门声音所需的代码更多的代码，包括一些看似旋转的代码。我想推荐您访问有关detecting screen/device rotation and setting the preview rotation的MSDN页面。再往下，您还将学习rotate a captured video的推荐方法。

Answer 2

尝试mediaCaptureElement.Source = null;然后await capture.StopPreviewAsync();然后capture.Dispose();

如何在不播放快门声的情况下处理MediaCapture

2 个答案: