How to write to file (encode) modified camera frames in Windows Phone 8 - opencv

Question

I have custom an camera app in Windows Phone 8. I need add a watermark image to each frame from camera capture and then record to a video.
I can customise each frame from the preview using the following code:
int[] pixelData = new int[(int)(camera.PreviewResolution.Width * camera.PreviewResolution.Height)];
camera.GetPreviewBufferArgb32(pixelData);
return pixelData;
and write it back to the preview.
my problem is that while I can show the frames on the screen while the user is recording a movie using the camera I cant find a working solution for WP8 to encode the frames and audio to save to a file.
I already tried opencv,libav and others without success,
if anyone can point me to the right direction it would be greatly appreciated.

Answer 1

You can do it like this.
private void GetCameraPicture_Click(object sender, RoutedEventArgs e)
{
Microsoft.Phone.Tasks.CameraCaptureTask cameraCaptureTask = new Microsoft.Phone.Tasks.CameraCaptureTask();
cameraCaptureTask.Completed += cct_Completed;
cameraCaptureTask.Show();
}
try
{
if (e.TaskResult == Microsoft.Phone.Tasks.TaskResult.OK)
{
var imageStream = e.ChosenPhoto;
var name = e.OriginalFileName;
using (MemoryStream mem = new MemoryStream())
{
TextBlock tb = new TextBlock() { Text = DateTime.Now.ToString("dd MMM yyyy, HH:mm"), Foreground = new SolidColorBrush(Color.FromArgb(128, 0, 0, 0)), FontSize = 40 };
BitmapImage finalImage = new BitmapImage();
finalImage.SetSource(imageStream);
WriteableBitmap wbFinal = new WriteableBitmap(finalImage);
wbFinal.Render(tb, null);
wbFinal.Invalidate();
wbFinal.SaveJpeg(mem, wbFinal.PixelWidth, wbFinal.PixelHeight, 0, 100);
mem.Seek(0, System.IO.SeekOrigin.Begin);
MediaLibrary lib = new MediaLibrary();
lib.SavePictureToCameraRoll("Copy" + name, mem.ToArray());
}
}
}
catch (Exception exp) { MessageBox.Show(exp.Message); }
Hope it may help you.