How to find out if SoftwareBitmap is fully black, when not on UI thread?

Question

Hi,

I have a SoftwareBitmap, and I'd like to know if it's fully black. This is due to a bug on MediaPlayer, but that's a totally different story.

I don't know how to convert it to a WritableBitmap on a non UI thread -- so, long story short, is it possible to get access to all the bytes from the software bitmap?
I know it's Bgra8, so I could simply test each 4 bytes to be 0xff, 0, 0, 0.

How do I do that?

Answer 1

I'll post this here for posterity. It IS possible

int width = 960, height = 540;
SoftwareBitmap soft = new SoftwareBitmap(BitmapPixelFormat.Bgra8, width, height);
...
var buffer = new Windows.Storage.Streams.Buffer ( (uint)( 4 * width * height));
soft.CopyToBuffer(buffer);

DataReader dr = DataReader.FromBuffer(buffer);
var bytes = new byte[4 * width * height];
dr.ReadBytes(bytes);