An internal matrix corresponding to a representation of a display screen and having transparency data of a macro block is accessed. Display plane data from either a first or second plane is read if the internal matrix indicates the macro block is non-translucent and from both planes when the internal matrix indicates translucency. A high-level external matrix having high-level external transparency data indicating transparency of pixels is accessed if the internal transparency data indicates the macro block includes a window boundary. Display plane data from either the first or second plane is read if the high-level external transparency data indicates a non-translucent pixel and from both planes when the internal matrix indicates translucency. A detailed external matrix is accessed if the internal transparency data indicates the macro block is translucent or if the high-level external transparency data indicates the pixel is translucent. The first and second planes are blended accordingly.