RGBToYCbCr[c_,opts___]:=
    Module[{k,cols,t,d,
        a={{.299,.587,.114},{-.299,-.587,.886}/1.772,{.701,-.587,-.114}/1.402}/255.,
        r,g,b,v={219,224,224},w={16,128,128},m,dflag=0},
      m=DisplayMode/.{opts}/.Options[RGBToYCbCr];
      If[m===True,dflag=1];
      d=Depth[c];
      If[d==2,t=a.c;If[dflag==0,Return[t],Return[v*t+w]]];
      If[d==3,t=Transpose[a.Transpose[c]];If[dflag==0,Return[t],Return[\
Transpose[v*Transpose[t]+w]]]];
      If[d==4,{r,g,b}=c;cols=Dimensions[r][[2]];
        t=
          Partition[Flatten[Transpose[{Flatten[r],Flatten[g],Flatten[b]}]],
            3];
        t=Transpose[a.Transpose[t]];
        If[dflag==1,t=Transpose[v*Transpose[t]+w]];
        Return[
          Table[Partition[Take[Flatten[t],{k,3*Length[t],3}],cols],{k,1,
              3}]];];
      ];