convertyuv.cpp

这程式是可以将 RGB的 BMP图片转换成 YUV格式的 CIF图片

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<iostream>

#define MY(a,b,c) (( a*  0.2989  + b*  0.5866  + c*  0.1145))
#define MU(a,b,c) (( a*(-0.1688) + b*(-0.3312) + c*  0.5000 + 128))
#define MV(a,b,c) (( a*  0.5000  + b*(-0.4184) + c*(-0.0816) + 128))

#define DY(a,b,c) (MY(a,b,c) > 255 ? 255 : (MY(a,b,c) < 0 ? 0 : MY(a,b,c)))
#define DU(a,b,c) (MU(a,b,c) > 255 ? 255 : (MU(a,b,c) < 0 ? 0 : MU(a,b,c)))
#define DV(a,b,c) (MV(a,b,c) > 255 ? 255 : (MV(a,b,c) < 0 ? 0 : MV(a,b,c)))

#define WIDTH 352
#define HEIGHT 288

void ReadBmp(unsigned char *RGB,FILE *fp);

void Convert(unsigned char *RGB, unsigned char *YUV);

int main()
{
    int i=1;
    char file[255];
    FILE *fp;
    FILE *fp2;
    unsigned char *YUV = NULL;
    unsigned char *RGB = NULL;
    unsigned int imgSize = WIDTH*HEIGHT;

    if((fp2 = fopen("C:\\test.cif", "wb")) == NULL)
    {
        return 0;
    }

    RGB = (unsigned char*)malloc(imgSize*6);
    YUV = (unsigned char*)malloc(imgSize + (imgSize>>1));
  
    for(i=1; i<2; i++)
    {
        sprintf(file, "C:\\test.bmp", i);
        if((fp = fopen(file, "rb")) == NULL) 
			continue;

        printf("Open file: %s\n", file);
        ReadBmp(RGB, fp);
		Convert(RGB, YUV);
        fwrite(YUV, 1, imgSize+(imgSize>>1), fp2);
        fclose(fp);
    }

    fclose(fp2);
    if(RGB)
        free(RGB);

    if(YUV)
        free(YUV);

    printf("done\n");
    system("pause");
    return 1;
}

void ReadBmp(unsigned char *RGB,FILE *fp)
{
    int i,j;
    unsigned char temp;

    fseek(fp,54, SEEK_SET);

    fread(RGB+WIDTH*HEIGHT*3, 1, WIDTH*HEIGHT*3, fp);
    for(i=HEIGHT-1,j=0; i>=0; i--,j++)
    {
        memcpy(RGB+j*WIDTH*3,RGB+WIDTH*HEIGHT*3+i*WIDTH*3,WIDTH*3);
    }
   
    for(i=0; (unsigned int)i < WIDTH*HEIGHT*3; i+=3)
    {
        temp = RGB[i];
        RGB[i] = RGB[i+2];
        RGB[i+2] = temp;
    }
}

void Convert(unsigned char *RGB, unsigned char *YUV)
{
    unsigned int i,x,y,j;
    unsigned char *Y = NULL;
    unsigned char *U = NULL;
    unsigned char *V = NULL;
   
    Y = YUV;
    U = YUV + WIDTH*HEIGHT;
    V = U + ((WIDTH*HEIGHT)>>2);

    for(y=0; y < HEIGHT; y++)
        for(x=0; x < WIDTH; x++)
        {
            j = y*WIDTH + x;
            i = j*3;
            Y[j] = (unsigned char)(DY(RGB[i], RGB[i+1], RGB[i+2]));

            if(x%2 == 1 && y%2 == 1)
            {
                j = (WIDTH>>1) * (y>>1) + (x>>1);

                U[j] = (unsigned char)
                       ((DU(RGB[i  ], RGB[i+1], RGB[i+2]) +
                         DU(RGB[i-3], RGB[i-2], RGB[i-1]) +
                         DU(RGB[i  -WIDTH*3], RGB[i+1-WIDTH*3], RGB[i+2-WIDTH*3]) +
                         DU(RGB[i-3-WIDTH*3], RGB[i-2-WIDTH*3], RGB[i-1-WIDTH*3]))/4);

                V[j] = (unsigned char)
                       ((DV(RGB[i  ], RGB[i+1], RGB[i+2]) +
                         DV(RGB[i-3], RGB[i-2], RGB[i-1]) +
                         DV(RGB[i  -WIDTH*3], RGB[i+1-WIDTH*3], RGB[i+2-WIDTH*3]) +
                         DV(RGB[i-3-WIDTH*3], RGB[i-2-WIDTH*3], RGB[i-1-WIDTH*3]))/4);
            }

        }
}