- Jan 1, 1970
Is it really necessary to go to the trouble of converting CVBS
directly to digital with a high speed ADC? My approach would be to
find a circuit to decode from CVBS to digital YCbCr or RGB, inject the
overlay information, and then re-encode back to CVBS using a video
display circuit. Would the degradation in video quality due to
decoding and re-encoding really be noticeable?
Pure analog overlay injection could better preserve the video quality,
but is the complexity of preserving the color integrity worth it? The
Obsolete Motorola MC1378 "Color Television Composite Video Overlay
Synchronizer" would simplify this task if it were still produced
(http://www.directics.comshows some inventory of these devices).
I've implemented this circuit in both analog and digital. Perhaps you
could elaborate on the requirements ... if you're the OP.
You don't need an MC1378 do do this analog. If you could buy it, it's
not all you would need. You could generate your timing overlay in an
FPGA that was synchronized to the Hz scan rate, then use a multiplier
for the cookie cutter, as one of the other posters suggested.
More detail on the application is required for smarter discussion on
the options ;->