Android : Bitmap from Camera Preview using BitmapFactory.decodeByteArray 옵션

Comment 4 by justinbonnar, Apr 17, 2009

The preview data comes in a YUV 4:2:0 format. If you only need grayscale information, the first (width * 
height) bytes of the preview are provided as unsigned byte intensities. To decode the color information to RGB 
suitable for use with a Bitmap, I've ported the following code from Android's platform/hardware/msm7k.git/yuv420sp2rg/yuv420sp2rgb.c which accomplishes the same thing. This is 
obviously significantly slower than a native-code solution would be, but provides a useable workaround. 
You'll want to copy the provided preview array in your onPreviewFrame() callback and perform the decoding 
and processing in a separate thread.

    static public void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width, int height) {
    	final int frameSize = width * height;
    	
    	for (int j = 0, yp = 0; j < height; j++) {
    		int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
    		for (int i = 0; i < width; i++, yp++) {
    			int y = (0xff & ((int) yuv420sp[yp])) - 16;
    			if (y < 0) y = 0;
    			if ((i & 1) == 0) {
    				v = (0xff & yuv420sp[uvp++]) - 128;
    				u = (0xff & yuv420sp[uvp++]) - 128;
    			}
    			
    			int y1192 = 1192 * y;
    			int r = (y1192 + 1634 * v);
    			int g = (y1192 - 833 * v - 400 * u);
    			int b = (y1192 + 2066 * u);
    			
    			if (r < 0) r = 0; else if (r > 262143) r = 262143;
    			if (g < 0) g = 0; else if (g > 262143) g = 262143;
    			if (b < 0) b = 0; else if (b > 262143) b = 262143;
    			
    			rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);
    		}
    	}
    }

The int[] rgb buffer passed in should be at least width * height in length.

출처 : http://code.google.com/p/android/issues/detail?id=823