About ZedBoard's ADV7511 reference Designs

With the reference Design, there is a IP core that ADI provides .(axi_hdmi_tx_16b_v1_00_a).

Here is the question, How can i change the dataformt of output ,while the 16bits Ycbcr4:2:2 is set to be default. what if i want 8 bits YCbCy 4:1:1.

Or i just want to bypass the RGB input signals to output,while the RGB is 24bits, how can it be output though a 16 bits Port?

Any advices?