如何在 windows phone 8.1 中使用 MediaCapture 设置最大分辨率？

Question

我正在研究 windows phone 8.1(RT) 我使用 MediaCapture 拍照（请记住，对预览要拍摄的照片不感兴趣）。我使用了下面的代码，但是图片的质量很糟糕，在拍摄的图片中只能看到照亮的部分。

private static async Task<DeviceInformation> GetCameraID(Windows.Devices.Enumeration.Panel desiredCamera)
{
    // get available devices for capturing pictures
    DeviceInformation deviceID = (await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture))
        .FirstOrDefault(x => x.EnclosureLocation != null && x.EnclosureLocation.Panel == desiredCamera);

    if (deviceID != null) return deviceID;
    else throw new Exception(string.Format("Camera of type {0} doesn't exist.", desiredCamera));
}

public async Task takeAPicture()
{
    var cameraID = await GetCameraID(Windows.Devices.Enumeration.Panel.Back);
    captureManager = new MediaCapture();

    await captureManager.InitializeAsync(new MediaCaptureInitializationSettings
    {
        StreamingCaptureMode = StreamingCaptureMode.Video,
        PhotoCaptureSource = PhotoCaptureSource.VideoPreview,
        AudioDeviceId = string.Empty,
        VideoDeviceId = cameraID.Id
    });

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

    StorageFile photoFile = await KnownFolders.PicturesLibrary.CreateFileAsync("myFirstPhoto.jpg", CreationCollisionOption.GenerateUniqueName);
    //take a photo with choosen Encoding

    await captureManager.CapturePhotoToStorageFileAsync(ImageEncodingProperties.CreateJpeg(), photoFile);
    captureManager.Dispose();
}

感谢您的帮助。

Answer 1

您似乎正在配置 MediaCapture 以提供 "preview-quality" 照片。改为这样做：

await captureManager.InitializeAsync(new MediaCaptureInitializationSettings
{
    StreamingCaptureMode = StreamingCaptureMode.Video,
    PhotoCaptureSource = PhotoCaptureSource.Photo, // I believe your bug was here
    AudioDeviceId = string.Empty,
    VideoDeviceId = cameraID.Id
});

或者实际上，只需尝试使用大多数这些属性的默认值，并且只设置 VideoDeviceId 以选择摄像机。它应该有助于缩小问题范围。

至于设置更高的照片捕获分辨率，这样的方法可能有效：

private async Task SetPhotoResolution()
{
    var resolutions = _captureManager.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.Photo).Select(x => x as VideoEncodingProperties);

    var maxRes = resolutions.OrderByDescending(x => x.Height * x.Width).FirstOrDefault();

    await _captureManager.VideoDeviceController.SetMediaStreamPropertiesAsync(MediaStreamType.Photo, maxRes);
}

请确保照片分辨率的纵横比与预览分辨率的纵横比相匹配，否则在某些 phone 的边缘附近可能会出现条纹。

此外，我测试的 phone 仅返回 NV12 VideoEncodingProperties 用于 MediaStreamType.Photo 流上的 GetAvailableMediaStreamProperties 调用。您可能需要在不同的设备上处理也包含 ImageEncodingProperties 的枚举。

如何在 windows phone 8.1 中使用 MediaCapture 设置最大分辨率？

How to set maximum resolution with MediaCapture in windows phone 8.1?

c#

windows-runtime

windows-phone-8.1