NV21 转YUY2

void NV21_2_YUY2(char *src, char *dst, int width, int height) {
    int size = width*height;
    char* pSrcUV = src + size;
    for(int i = 0; i < size; ++ i){
        dst[i*2] = src[i];
    }
    int p1 = 0;
    int vPos = 0;
    for(int y = 0; y < height; ++ y){
        //int vPos = y/2*width;
        if(y%2 != 0){
            vPos -= width;
        }
        for (int x = 0; x < width/2; ++x) {
            int uPos = vPos + 1;
            int p2 = p1 + 2;//yv point
            dst[p1 + 1] = pSrcUV[uPos];
            dst[p2 + 1] = pSrcUV[vPos];
            vPos += 2;
            p1 += 4;
        }
    }
}

void  YUY2_2_NV21(char *src, char *dst, int width, int height) {
    char* pDstY  = dst;
    char* pDstUV = dst + width*height;
    int halfH = height/2;
    int halfW = width/2;
    int stride = width*2;
    int p1, p2, p3, p4;
    int index = 0;
    for(int y = 0; y< halfH; ++ y){
        for(int x = 0; x < halfW; ++ x){
            //int px = 2*x;
            //int py = 2*y;
            //int index = py*stride + px*2;
            p1 = (index);
            p2 = (index) + 2;
            p3 = (index) + stride;
            p4 = (index) + stride + 2;
            pDstUV[y*width + x*2] = (src[p2+1] + src[p4+1])/2;
            pDstUV[y*width + x*2 + 1] = (src[p1+1] + src[p3+1])/2;
            pDstY[p1>>1] = src[p1];
            pDstY[p2>>1] = src[p2];
            pDstY[p3>>1] = src[p3];
            pDstY[p4>>1] = src[p4];
            index += 4;
        }
        index += stride;
    }
}