Just to notify some info about how to control your TV over HDMI cable.
I found some info in the arduino forum:
Yes, you can control over TV over HDMI cable using an arduino.
I’m searching for a way to send Closed Caption (CC) signal to TV, but it is not possible using HDMI cable. I think it is possible to send data directly over CEC interface (I²C) and use a board to get this data and show CC in a LED display.