mat3 yiq2rgb_mat = mat3(
   1.0, 1.0, 1.0,
   0.956, -0.2720, -1.1060,
   0.6210, -0.6474, 1.7046
);

vec3 yiq2rgb(vec3 yiq)
{
   return (yiq * yiq2rgb_mat);
}

mat3 yiq_mat = mat3(
      0.2989, 0.5959, 0.2115,
      0.5870, -0.2744, -0.5229,
      0.1140, -0.3216, 0.3114
);

vec3 rgb2yiq(vec3 col)
{
   return (col * yiq_mat);
}