用前置摄像机录制视频- WP8 - C#

Question

我的windows应用程序需要从前面的摄像头录制一段视频，并通过网络服务发送给服务器。

在这里，当我试图录制来自front-camera的视频时，我得到了mirror inverted video。意味着前摄像头记录180度旋转视频。

我认为可能唯一的解决办法是将录制的视频流旋转回180度。

问题：

• 在wp8中，是否有其他解决方案可以用前置摄像机录制适当的视频？
• 如果没有，如何旋转视频流180度？有任何c# API来做吗..？

编辑：

下面是我正在使用的代码：

用于VideoBrush的XAML代码

    <Canvas x:Name="CanvasLayoutRoot" RenderTransformOrigin="0.5 0.5"
            Width="{Binding ActualHeight, ElementName=LayoutRoot}"
            Height="{Binding ActualWidth, ElementName=LayoutRoot}"
            Margin="-160 0 0 0">
        <!--Background="Transparent"-->

        <Canvas.Background>
            <VideoBrush x:Name="videoBrush" />
        </Canvas.Background>
        <Canvas.RenderTransform>
            <RotateTransform x:Name="rt" />
        </Canvas.RenderTransform>

    </Canvas>

初始化相机

    public async void InitializeVideoRecorder()
    {
        try
        {
            if (videoCapture == null)
            {
                // below line of code will detect if "Front Camera" is available or not
                // if availble, then open it or it will open "Back Camera"

                videoCapture = await AudioVideoCaptureDevice.OpenAsync(
                    AudioVideoCaptureDevice.AvailableSensorLocations.Contains(CameraSensorLocation.Front) ? CameraSensorLocation.Front : CameraSensorLocation.Back,
                    new Windows.Foundation.Size(640, 480));

                videoCapture.RecordingFailed += videoCapture_RecordingFailed;

                videoCapture.SetProperty(KnownCameraGeneralProperties.EncodeWithOrientation, videoCapture.SensorRotationInDegrees);

                // Initialize the camera if it exists on the phone.
                if (videoCapture != null)
                {
                    videoBrush.SetSource(videoCapture);
                    if (!AudioVideoCaptureDevice.AvailableSensorLocations.Contains(CameraSensorLocation.Front))
                    {
                        rt.Angle = videoCapture.SensorRotationInDegrees;
                    }
                    else
                    {
                        rt.Angle = -(videoCapture.SensorRotationInDegrees);
                    }
                }
                else
                {
                    MessageBox.Show("Unable to load Camera. Please try again later.", App.appName, MessageBoxButton.OK);
                    NavigationService.GoBack();
                }
            }
        }
        catch (Exception ex)
        {
            (new WebServices()).catchExceptions(ex);
            NavigationService.GoBack();
        }
    }

启动VideoCapture

    private async Task StartVideoRecording()
    {
        try
        {
            // Gets the application data folder
            StorageFolder applicationFolder = ApplicationData.Current.LocalFolder;
            StorageFolder transfersFolder = await (await applicationFolder.GetFolderAsync("Shared")).GetFolderAsync("Transfers");

            // Create the file specified in the application data folder
            videoFileName = selectedQue.response.template_id + "_" + selectedQue.response.id + "_" + selectedQue.response.invite_id +".mp4";
            StorageFile storageFile = await transfersFolder.CreateFileAsync(videoFileName, CreationCollisionOption.ReplaceExisting);

            // Open a file stream, ready to write video data
            randomAccessStream = await storageFile.OpenAsync(FileAccessMode.ReadWrite);

            // Video recording to the specified stream
            await videoCapture.StartRecordingToStreamAsync(randomAccessStream);
            isRecordingStarted = true;

            //timer = "0:00";
            tbTimer.Text = "0:00";
            dt.Start();
        }
        catch (Exception ex)
        {
            (new WebServices()).catchExceptions(ex);
        }
    }

Answer 1

经过24小时的努力，我终于用下面的方法解决了我的问题。

通过旋转视频引起问题的代码行在下面。

videoCapture.SetProperty(KnownCameraGeneralProperties.EncodeWithOrientation, videoCapture.SensorRotationInDegrees);

这里videoCapture是AudioVideoCaptureDevice的对象

在使用前摄像头时，我们需要反转cameraSensor的旋转。

因此，我使用了上面提到的相同的代码，在这段videoCapture.SetProperty代码行中做了一个小小的修改。正确的代码行如下。

videoCapture.SetProperty(KnownCameraGeneralProperties.EncodeWithOrientation, -(videoCapture.SensorRotationInDegrees));

我只是在videoCapture.SensorRotationInDegrees前面加了一个负号(-)来倒置它。

希望这对大家都有帮助。

Answer 2

在过去，这对我来说是可行的，它只是一个条形码扫描器应用程序，我是为了满足功能需求而编写的。我把变换放到了<VideoBrush>上。

<Grid x:Name="ContentPanel" Margin="12,0,12,0">
    <Canvas x:Name="cam_canvas" Width="480" Height="480">                
        <Canvas.Background>
            <VideoBrush x:Name="cam_video_brush" Stretch="None">
                <VideoBrush.RelativeTransform>
                    <CompositeTransform Rotation="90" CenterX="0.5" CenterY="0.5" />
                </VideoBrush.RelativeTransform>
            </VideoBrush>
        </Canvas.Background>
    </Canvas>
</Grid>