#define CLIP(color) (unsigned char)((color>0xFF)?0xff:((color<0)?0:color))void equalize (unsigned char *src, int width, int height, int format){unsigned int histo[256];unsigned int functequalize[256];unsigned int meanhisto = 0;unsigned int mean =0;int i ,j ;int index,U,V;unsigned char* ptsrc = src;unsigned char *u;unsigned char *v;int size ;/*  format yuv420p *//* compute histo */memset(histo,0,256);size = width*height; for (i=0;i<width*height;i++){ index=*ptsrc++; histo[index]++; } /* normalize histo 8 bits*/ for (i=0;i< 256;i++){ histo[i] = (histo[i] << 8) / size; }  /*each histo value cannot be more than width*height for 640x480  307200 fit in 2^19  */ /* now compute the mean histo value so max 307200*256 fit in 2^27 */  for(i=0;i<256;i++) 	meanhisto += histo[i];	/*normalize menahisto 10 bits*/	// printf("meanhisto %d \n",meanhisto);/*compute the functequalize now */for (i=0;i <256;i++){mean = 0; for(j=0;j< i;j++) 	mean += histo[j];if (meanhisto) functequalize[i] = CLIP(((mean << 18) / meanhisto));else functequalize[i] = 255;}ptsrc = src;u = src + (width*height);v = u + (width*height >> 2);/* apply the cange to y channel */for (i = 0 ;i < width*height ; i++){		index = *ptsrc;	 	*ptsrc++ = (functequalize[index]);	/*	if (!(i & 0xFFFFFFC0)){	U = *u-128;	*u++ = CLIP((U * functequalize[index] >> 8)+128);	V = *v-128;	*v++ = CLIP((V * functequalize[index] >> 8)+128);	}	*/	}//for (i = 0; i < width*height>>1; i++)//	*u++= 0x80;	}