Question

I’m using the PhotoCaptureDevice class and I can capture the camera frame, but when I am getting an error while copying the image data in the CameraCaptureFrame.CaptureSequence of the CameraCaptureSequence into a MemoryStream and then save it in the Camera Roll. This is the code snippet of what I’m trying to do.

PhotoCaptureDevice cam;    
cam = await PhotoCaptureDevice.OpenAsync(<front/rear depending on user input>,<resolution depends on user input>);

CameraCaptureSequence seq;
seq = cam.CreateCaptureSequence(1);

cam.SetProperty(KnownCameraGeneralProperties.PlayShutterSoundOnCapture, true);

MemoryStream captureStream1 = new MemoryStream();
seq.Frames[0].CaptureStream = captureStream1.AsOutputStream();//This stream is for saving the image data to camera roll

await cam.PrepareCaptureSequenceAsync(seq);
await seq.StartCaptureAsync();

bool a = seq.Frames[0].CaptureStream.Equals(0);//This value is false during debugging
if(capturestream1.Length>0)//This condition evaluates to false
{
MediaLibrary library = new MediaLibrary();
Picture picture1 = library.SavePictureToCameraRoll("image1", captureStream1);
}
else
{
//Logic to handle condition
}

As I’ve added in the comments, the variable bool a evaluates to false which I checked by debugging the code. But for some reason the capturestream1.Length property is 0.

Answer 1

Here’s a code snippet on how to capture a sequence with a single image and saving that image to the MediaLibrary. Obviously this is a bit of a trivial example for this API since sequence are really good for capturing multiple images and meshing them up together with post-processing.

private async void MainPage_Loaded(object sender, RoutedEventArgs e)
{
    using (MemoryStream stream = new MemoryStream())
    using (var camera = await PhotoCaptureDevice.OpenAsync(CameraSensorLocation.Back,
            PhotoCaptureDevice.GetAvailableCaptureResolutions(CameraSensorLocation.Back).First()))
    {
        var sequence = camera.CreateCaptureSequence(1);
        sequence.Frames[0].CaptureStream = stream.AsOutputStream();
        camera.PrepareCaptureSequenceAsync(sequence);
        await sequence.StartCaptureAsync();

        stream.Seek(0, SeekOrigin.Begin);

        using (var library = new MediaLibrary())
        {
            library.SavePictureToCameraRoll("currentImage.jpg", stream);
        }
    }
}

When you run this code snippet you can see the image stored on the device:

You can find a full working sample as part of Nokia’s Camera Explorer app that demos end-to-end usecases for the WP8 camera APIs: http://projects.developer.nokia.com/cameraexplorer