如何更改 Windows Phone 8,8.1 中的默认视频捕获分辨率

我想构建一个应用程序，让用户可以选择视频录制的分辨率大小（例如全高清-1920x1080 或 vga-640x480 等）

我正在使用下面的代码，但是当我在 720p 模拟器上运行它时，它显示了其他部分的消息，即相机不支持此功能。 （当我将值 800,450 更改为 640,480 时，相机开始正常工作）

try
           {
              //string deviceName = DeviceStatus.DeviceName;
               //var deviceName = DeviceStatus.DeviceName;
               //if (deviceName.Contains("RM-885"))
               //{
                   Windows.Foundation.Size initialResolution = new Windows.Foundation.Size(800, 450);
                   Windows.Foundation.Size previewResolution = new Windows.Foundation.Size(800, 450);
                   Windows.Foundation.Size captureResolution = new Windows.Foundation.Size(800, 450);
                   if (AudioVideoCaptureDevice.AvailableSensorLocations.Contains(CameraSensorLocation.Back))
                   {
                       pops = await AudioVideoCaptureDevice.OpenAsync(CameraSensorLocation.Back, initialResolution);
                       await pops.SetPreviewResolutionAsync(previewResolution);
                       await pops.SetCaptureResolutionAsync(captureResolution);    


                   }
               }
          // }

           catch (Exception p) { Debug.WriteLine(p.Message); }

            try
            {
                if(pops != null)
                {


                    // create the videobrush for the viewfinder
                    videoRecordBrush = new VideoBrush();
                    videoRecordBrush.SetSource(pops);
                    // display the viewfinder image 
                    viewfinderRectangle.Fill = videoRecordBrush;
                    //shows available resolution message 
                    MessageBox.Show("statrt recording ");
                    MessageBox.Show(pops.PreviewResolution.ToString());
                    MessageBox.Show(pops.CaptureResolution.ToString());


                }
                else
                {
                    MessageBox.Show("camera not support this ");
                }
            }
            catch(Exception ex)
            {
                MessageBox.Show("exception" + ex);
            }
        }

这是在视频模式下更改分辨率的正确代码吗？或者还有其他方法吗？

在 Windows Phone 8.1 中，您可以更改纵横比两者的视频预览 and 拍摄的照片通过改变MediaCapture.VideoDeviceController环境。

视频预览是在实际拍摄照片之前您可以从屏幕上看到的相机视图。这是至关重要的纵横比视频预览和拍摄的照片相同避免奇怪的线条和黑条在拍摄的照片中。换句话说，就是保证拍摄出来的照片和你在屏幕上看到的预览一模一样。

首先，您可以检查 Windows Phone 8.1 中的所有可用分辨率。在下面的代码中，我演示了如何检查可用的分辨率用于视频预览和拍摄的照片。返回的高度和宽度是您手机可用的分辨率，例如 i=0、height=1080、width=1920 (1920x1080)。请在高度和宽度线上调试以检查不同的分辨率。

MediaCapture mediacapture = new MediaCapture();
await mediacapture.InitializeAsync(new MediaCaptureInitializationSettings{});
var previewResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.VideoPreview);
var photoResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.Photo);

        VideoEncodingProperties allResolutionsAvailable;
        uint height, width;
  //use debugger at the following line to check height & width for video preview resolution
        for (int i = 0; i < previewResolution.Count; i++)
        {
            allResolutionsAvailable = previewResolution[i] as VideoEncodingProperties;
            height = allResolutionsAvailable.Height;
            width = allResolutionsAvailable.Width;
        }
  //use debugger at the following line to check height & width for captured photo resolution
        for (int i = 0; i < photoResolution.Count; i++)
        {
            allResolutionsAvailable = photoResolution[i] as VideoEncodingProperties;
            height = allResolutionsAvailable.Height;
            width = allResolutionsAvailable.Width;
        }

检查了所有可用的分辨率后height and width上面的参数，你可以选择特定的分辨率您想要使用 .ElementAt(int) 方法，例如.ElementAt(0)

var selectedPreviewResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.VideoPreview).ElementAt(1);
var selectedPhotoResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.Photo).ElementAt(1);

await mediacapture.VideoDeviceController.SetMediaStreamPropertiesAsync(MediaStreamType.VideoPreview, selectedPreviewResolution);
await mediacapture.VideoDeviceController.SetMediaStreamPropertiesAsync(MediaStreamType.Photo, selectedPhotoResolution);

//in .xaml <CaptureElement Name="viewfinder"/>
viewfinder.Source = mediacapture;
//to set video preview upright
mediacapture.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
await mediacapture.StartPreviewAsync();

以相同的宽高比分别为视频预览和捕获的照片设置 .ElementAt(i)。 以下是诺基亚 Lumia 1520 可用的分辨率。

视频预览

• 我......高度*宽度..纵横比
• 0.....1080*1920....16:9
• 1......720*1280.....16:9
• 2......450*800......16:9
• 3....1080*1440......4:3
• 4......768*1024......4:3
• 5......480*640......4:3

拍摄的照片

• 我....高度*宽度..纵横比
• 0....3024*4992.......4:3
• 1.....1936*2592...162:121
• 2.....1536*2048.......4:3
• 3......480*640......4:3
• 4.....3024*5376.....16:9
• 5.....1728*3072.....16:9
• 6.....1456*2592...162:91

最后，如果你想使用最大分辨率适用于视频预览和拍摄的照片，您可以使用以下代码。

//maximum resolution for 4:3 aspect ratio 
 var maxPhotoResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.Photo).Aggregate((i1, i2) => (i1 as VideoEncodingProperties).Height > (i2 as VideoEncodingProperties).Height ? i1 : i2);
 var maxPreviewResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.VideoPreview).Aggregate((i1, i2) => (i1 as VideoEncodingProperties).Height > (i2 as VideoEncodingProperties).Height ? i1 : i2);

//maximum resolution for 16:9 aspect ratio 
 var maxPhotoResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.Photo).Aggregate((i1, i2) => (i1 as VideoEncodingProperties).Width > (i2 as VideoEncodingProperties).Width ? i1 : i2);
 var maxPreviewResolution = mediacapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.VideoPreview).Aggregate((i1, i2) => (i1 as VideoEncodingProperties).Width > (i2 as VideoEncodingProperties).Width ? i1 : i2);

await mediacapture.VideoDeviceController.SetMediaStreamPropertiesAsync(MediaStreamType.Photo, maxPhotoResolution);
await mediacapture.VideoDeviceController.SetMediaStreamPropertiesAsync(MediaStreamType.VideoPreview, maxPreviewResolution);