RGB24 to YUV420

#include "StdAfx.h" #include "RGB2YUV.h" CRGB2YUV::CRGB2YUV(void) { } CRGB2YUV::~CRGB2YUV(void) { } void CRGB2YUV::Free() { memset(RGB2YUV_YR, 0, sizeof(RGB2YUV_YR)); memset(RGB2YUV_YG, 0, sizeof(RGB2YUV_YR)); memset(RGB2YUV_YB, 0, sizeof(RGB2YUV_YR)); memset(RGB2YUV_UR, 0, sizeof(RGB2YUV_YR)); memset(RGB2YUV_UG, 0, sizeof(RGB2YUV_YR)); memset(RGB2YUV_UBVR, 0, sizeof(RGB2YUV_YR)); memset(RGB2YUV_VG, 0, sizeof(RGB2YUV_YR)); memset(RGB2YUV_VB, 0, sizeof(RGB2YUV_YR)); } // // Table used for RGB to YUV420 conversion // void CRGB2YUV::InitLookupTable() { int i=0; for (i = 0; i < 256; i++) RGB2YUV_YR[i] = (float)65.481 * (i<<8); for (i = 0; i < 256; i++) RGB2YUV_YG[i] = (float)128.553 * (i<<8); for (i = 0; i < 256; i++) RGB2YUV_YB[i] = (float)24.966 * (i<<8); for (i = 0; i < 256; i++) RGB2YUV_UR[i] = (float)37.797 * (i<<8); for (i = 0; i < 256; i++) RGB2YUV_UG[i] = (float)74.203 * (i<<8); for (i = 0; i < 256; i++) RGB2YUV_VG[i] = (float)93.786 * (i<<8); for (i = 0; i < 256; i++) RGB2YUV_VB[i] = (float)18.214 * (i<<8); for (i = 0; i < 256; i++) RGB2YUV_UBVR[i] = (float)112 * (i<<8); } // // Convert from RGB24 to YUV420 // bool CRGB2YUV::ConvertRGB2YUV(int w, int h, unsigned char *bmp, unsigned char *yuv) { unsigned char *u,*v,*y,*uu,*vv; unsigned char *pu1,*pu2,*pu3,*pu4; unsigned char *pv1,*pv2,*pv3,*pv4; unsigned char *r,*g,*b; int i,j; uu=new unsigned char[w*h]; vv=new unsigned char[w*h]; if(uu==NULL || vv==NULL) return false; y=yuv; u=uu; v=vv; //Get r,g,b pointers from bmp image data.... r=bmp; g=bmp+1; b=bmp+2; //Get YUV values for rgb values... for(i=0;i<h;i++) { for(j=0;j<w;j++) { *y++=( RGB2YUV_YR[*r] +RGB2YUV_YG[*g] +RGB2YUV_YB[*b] +1048576) >>16; *u++=(-RGB2YUV_UR[*r] -RGB2YUV_UG[*g] +RGB2YUV_UBVR[*b] +8388608) >>16; *v++=( RGB2YUV_UBVR[*r] -RGB2YUV_VG[*g] -RGB2YUV_VB[*b] +8388608) >>16; r+=3; g+=3; b+=3; } } // Now sample the U & V to obtain YUV 4:2:0 format // Sampling mechanism... /* @ -> Y # -> U or V @ @ @ @ # # @ @ @ @ @ @ @ @ # # @ @ @ @ */ // Get the right pointers... u=yuv+w*h; v=u+(w*h)/4; // For U pu1=uu; pu2=pu1+1; pu3=pu1+w; pu4=pu3+1; // For V pv1=vv; pv2=pv1+1; pv3=pv1+w; pv4=pv3+1; // Do sampling.... for(i=0;i<h;i+=2) { for(j=0;j<w;j+=2) { *u++=(*pu1+*pu2+*pu3+*pu4)>>2; *v++=(*pv1+*pv2+*pv3+*pv4)>>2; pu1+=2; pu2+=2; pu3+=2; pu4+=2; pv1+=2; pv2+=2; pv3+=2; pv4+=2; } pu1+=w; pu2+=w; pu3+=w; pu4+=w; pv1+=w; pv2+=w; pv3+=w; pv4+=w; } delete uu; delete vv; return true; }