RGB24 <--> YUV422 convert에 관한 내용 부탁....

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void RGB_YCbCr(int s_Red, int s_Green, int s_Blue, int *s_Y, int *s_Cb, int *s_Cr)
{ /* 변환과정에서 색감 손실이 약 5% 까지 발생 */
#if DEF_USE_RY_TYPE == 0
 /*
  Y  =  0.29900Red + 0.58700Green + 0.11400Blue =   ( 77Red/256) + (150Green/256) + ( 29Blue/256)
  Cb = -0.16874Red - 0.33126Green + 0.50000Blue = - ( 44Red/256) - ( 87Green/256) + (131Blue/256) {+128}
  Cr =  0.50000Red - 0.41869Green - 0.08131Blue =   (131Red/256) - (110Green/256) + ( 21Blue/256) {+128}
 */
 s_Red &= 0xff, s_Green &= 0xff, s_Blue  &= 0xff;
 *s_Y  = (int)(  (( 77 * s_Red) >> 8) + ((150 * s_Green) >> 8) + (( 29 * s_Blue) >> 8)       );
 *s_Cb = (int)( -(( 44 * s_Red) >> 8) - (( 87 * s_Green) >> 8) + ((131 * s_Blue) >> 8) + 128 );
 *s_Cr = (int)(  ((131 * s_Red) >> 8) - ((110 * s_Green) >> 8) - (( 21 * s_Blue) >> 8) + 128 );
 *s_Y  = (int)(  (*s_Y  > 0) ? *s_Y  : 0);  *s_Y  = (int)((*s_Y  < 255) ? *s_Y  : 255        );
 *s_Cb = (int)(  (*s_Cb > 0) ? *s_Cb : 0);  *s_Cb = (int)((*s_Cb < 255) ? *s_Cb : 255        );
 *s_Cr = (int)(  (*s_Cr > 0) ? *s_Cr : 0);  *s_Cr = (int)((*s_Cr < 255) ? *s_Cr : 255        );
#else
 /*
  Y  =  0.29900Red + 0.58700Green + 0.11400Blue =   (19595.264  Red/65536) + (38469.632  Green/65536) + (7471.104  Blue/65536)
  Cb = -0.16874Red - 0.33126Green + 0.50000Blue = - (11058.54464Red/65536) - (21709.45536Green/65536) + (32768.0   Blue/65536) {+128}
  Cr =  0.50000Red - 0.41869Green - 0.08131Blue =   (32768.0    Red/65536) - (27439.26784Green/65536) + (5328.73216Blue/65536) {+128}
 */
 s_Red &= 0xff, s_Green &= 0xff, s_Blue  &= 0xff;
 *s_Y  = (int)(  ((19595 * s_Red) >> 16) + ((38470 * s_Green) >> 16) + ((7471  * s_Blue) >> 16)       );
 *s_Cb = (int)( -((11059 * s_Red) >> 16) - ((21709 * s_Green) >> 16) + ((32768 * s_Blue) >> 16) + 128 );
 *s_Cr = (int)(  ((32768 * s_Red) >> 16) - ((27439 * s_Green) >> 16) - ((5329  * s_Blue) >> 16) + 128 );
 *s_Y  = (int)(  (*s_Y  > 0) ? *s_Y  : 0);  *s_Y  = (int)((*s_Y  < 255) ? *s_Y  : 255        );
 *s_Cb = (int)(  (*s_Cb > 0) ? *s_Cb : 0);  *s_Cb = (int)((*s_Cb < 255) ? *s_Cb : 255        );
 *s_Cr = (int)(  (*s_Cr > 0) ? *s_Cr : 0);  *s_Cr = (int)((*s_Cr < 255) ? *s_Cr : 255        );
#endif
 return;
}

void YCbCr_RGB(int s_Y, int s_Cb, int s_Cr, int *s_Red, int *s_Green, int *s_Blue)
{ /* 변환과정에서 색감 손실이 약 5% 까지 발생 */
#if DEF_USE_RY_TYPE == 0 /* 소수점 이하 3자리까지만 계산 */
 /*
  Red   = 1.00000Y + 1.40200Cr             = s_Y + (359s_Cr{-128}/256)
  Green = 1.00000Y - 0.34414Cb - 0.71414Cr = s_Y - ( 88s_Cb{-128}/256) - (183s_Cr{-128}/256)
  Blue  = 1.00000Y + 1.77200Cb             = s_Y + (454s_Cb{-128}/256)
 */
 s_Y &= 0xff, s_Cb &= 0xff, s_Cr &= 0xff;
 s_Cb -= 128, s_Cr -= 128;
 *(s_Red)   = (int)( s_Y + ((359*s_Cr)/256) );
 *(s_Green) = (int)( s_Y - ((88*s_Cb)/256) - ((183*s_Cr)/256) );
 *(s_Blue)  = (int)( s_Y + ((454*s_Cb)/256) );
#else                   /* 소수점 이하 6자리까지만 계산 */
 /*
  Red   = 1.00000Y + 1.40200Cr             = s_Y + (91881.472  s_Cr{-128}/32768)
  Green = 1.00000Y - 0.34414Cb - 0.71414Cr = s_Y - (22553.55904s_Cb{-128}/32768) - (46801.87904s_Cr{-128}/65536)
  Blue  = 1.00000Y + 1.77200Cb             = s_Y + (116129.792 s_Cb{-128}/32768)
 */
 s_Y &= 0xff, s_Cb &= 0xff, s_Cr &= 0xff;
 s_Cb -= 128;
 s_Cr -= 128;
 *(s_Red)   = (int)( s_Y + ((91881 *s_Cr)/65536) );
 *(s_Green) = (int)( s_Y - ((22554 *s_Cb)/65536) - ((46802*s_Cr)/65536) );
 *(s_Blue)  = (int)( s_Y + ((116130*s_Cb)/65536) );
#endif
 return;
}