ADC and HDMI clock synchornization


I am making a simple video synthesizer using the HDMI shield (on the Mojo). I have successfully generated my signal with the HDMI shield, but now I’d like to change the red/green/blue amount based on the input from the ADC. The ADC tutorial uses a PWM to control the LEDs based on the input from the ADC, but I’m just trying to get an 8 bit value out of it.

Also, it seems that since the ADC and the HDMI processing are on different clock domains, the signals from the ADC will not correctly “register” with the HDMI domain.

I tried setting the clock of the ADC to the clock that’s provided by the HDMI Encoder component, but I get an error during synthesis.

Can anyone point me in the general direction of how to convert the input of the ADC into a simple 8 bit value between 0-254 that I can then use to set the value of the,.green, and .blue values?

Thanks in advance.