Controlling and detecting alignment of composite video color frames

A method of controlling and detecting the alignment of a color frame phase from a composite analog video signal comprising the steps of:

• decoding the composite analog video signal to generate a color frame signal and a component digital video signal;
• inserting based upon the color frame signal a flag signal into the component digital video signal;
• and
• capturing the component digital video signal based upon the flag signal so that the captured component digital video signal is in color frame phase with a stored reference component digital video signal.

An apparatus for controlling and detecting alignment of color frame phase in a composite analog video signal comprising:

• a decoder having as an input the composite analog video signal representing a test sequence processed by a system under test and having as outputs a component digital video signal and a color frame signal;
• a flag insertion circuit having as inputs the component digital video signal and the color frame signal and having as an output a modified component digital video signal with a flag signal generated as a function of the component digital video signal and the color frame signal inserted into one of the components of the component digital video signal at a specified location and for a specified duration;
• and
• an analyzer having as an input the modified component digital video signal for comparison with a reference component digital video signal representing the test sequence as input to the system under test, the analyzer using the flag signal in the modified component digital video signal to capture the modified component digital video signal when the color phase is aligned with that of the reference component digital video prior to such comparison.