Rotate YUV420/NV21 Image in android

问题

In PreviewCall back of surface we are getting YUV420SP format in camera Preview but due to wrong rotation of that image I want to perform correct rotation of YUV image as I need to send it through network.so correct rotation need to be applied.

I found this link it does correct rotation but image loose the color.

http://www.wordsaretoys.com/2013/10/25/roll-that-camera-zombie-rotation-and-coversion-from-yv12-to-yuv420planar/

also checked Rotate an YUV byte array on Android but it does not show image properly.

I do have checked links on stckoverflow but none of them have satisfactory answer about correctly using the code in android environment.

do any one have idea how to correctly rotate NV21 Image bytes[] with retaining its color information correctly.

回答1:

If you just want to rotate NV21, following code will be helpful. (I modified the code from here)

public static void rotateNV21(byte[] input, byte[] output, int width, int height, int rotation) {
        boolean swap = (rotation == 90 || rotation == 270);
        boolean yflip = (rotation == 90 || rotation == 180);
        boolean xflip = (rotation == 270 || rotation == 180);
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                int xo = x, yo = y;
                int w = width, h = height;
                int xi = xo, yi = yo;
                if (swap) {
                    xi = w * yo / h;
                    yi = h * xo / w;
                }
                if (yflip) {
                    yi = h - yi - 1;
                }
                if (xflip) {
                    xi = w - xi - 1;
                }
                output[w * yo + xo] = input[w * yi + xi];
                int fs = w * h;
                int qs = (fs >> 2);
                xi = (xi >> 1);
                yi = (yi >> 1);
                xo = (xo >> 1);
                yo = (yo >> 1);
                w = (w >> 1);
                h = (h >> 1);
                // adjust for interleave here
                int ui = fs + (w * yi + xi) * 2;
                int uo = fs + (w * yo + xo) * 2;
                // and here
                int vi = ui + 1;
                int vo = uo + 1;
                output[uo] = input[ui]; 
                output[vo] = input[vi]; 
            }
        }
    }   

来源：https://stackoverflow.com/questions/23107057/rotate-yuv420-nv21-image-in-android