Just to notify some info about how to control your TV over HDMI cable.
I found some info in the arduino forum:
http://forum.arduino.cc/index.php/topic,22327.0.html
It pointed me to:
http://www.andrewncarr.com/hdmi/index.html
https://code.google.com/p/cec-arduino/
Yes, you can control over TV over HDMI cable using an arduino.
More info:
http://elinux.org/CEC_%28Consumer_Electronics_Control%29_over_HDMI
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.
Alan C. Assis 