mult_matrix
mult_matrix(r, g, b, rec709_to_240m);
mult_matrix(r, g, b, rec709_to_170m);
mult_matrix(r, g, b, rec709_to_ebu);
mult_matrix(r, g, b, rec709_to_ntsc1953);
mult_matrix(r, g, b, rec709_to_oprgb);
mult_matrix(r, g, b, rec709_to_bt2020);
mult_matrix(r, g, b, rec709_to_dcip3);