android - Convert bitmap array to YUV (YCbCr NV21) -

how convert bitmap returned bitmapfactory.decodefile() yuv format (simillar camera's onpreviewframe() returns in byte array)?

here code works:

    // untested function     byte [] getnv21(int inputwidth, int inputheight, bitmap scaled) {          int [] argb = new int[inputwidth * inputheight];          scaled.getpixels(argb, 0, inputwidth, 0, 0, inputwidth, inputheight);          byte [] yuv = new byte[inputwidth*inputheight*3/2];         encodeyuv420sp(yuv, argb, inputwidth, inputheight);          scaled.recycle();          return yuv;     }      void encodeyuv420sp(byte[] yuv420sp, int[] argb, int width, int height) {         final int framesize = width * height;          int yindex = 0;         int uvindex = framesize;          int a, r, g, b, y, u, v;         int index = 0;         (int j = 0; j < height; j++) {             (int = 0; < width; i++) {                  = (argb[index] & 0xff000000) >> 24; // not used                 r = (argb[index] & 0xff0000) >> 16;                 g = (argb[index] & 0xff00) >> 8;                 b = (argb[index] & 0xff) >> 0;                  // known rgb yuv algorithm                 y = ( (  66 * r + 129 * g +  25 * b + 128) >> 8) +  16;                 u = ( ( -38 * r -  74 * g + 112 * b + 128) >> 8) + 128;                 v = ( ( 112 * r -  94 * g -  18 * b + 128) >> 8) + 128;                  // nv21 has plane of y , interleaved planes of vu each sampled factor of 2                 //    meaning every 4 y pixels there 1 v , 1 u.  note sampling every other                 //    pixel , every other scanline.                 yuv420sp[yindex++] = (byte) ((y < 0) ? 0 : ((y > 255) ? 255 : y));                 if (j % 2 == 0 && index % 2 == 0) {                      yuv420sp[uvindex++] = (byte)((v<0) ? 0 : ((v > 255) ? 255 : v));                     yuv420sp[uvindex++] = (byte)((u<0) ? 0 : ((u > 255) ? 255 : u));                 }                  index ++;             }         }     }