Answer by Max for Extract black and white image from android camera's NV21 format

I also had lots of headache because of this preview format.

The best I could find are these:

http://www.fourcc.org/yuv.php#NV21

http://v4l2spec.bytesex.org/spec/r5470.htm

It seems that the Y component is the first width*height bytes int the array you get.

Some more informational links:

http://msdn.microsoft.com/en-us/library/ms867704.aspx#yuvformats_yuvsampling

http://msdn.microsoft.com/en-us/library/ff538197(v=vs.85).aspx

Hope this helps.