Are you trying to (like black bars) or create a specific signal ?
Used to generate a perfectly black or "blank" High Definition frame to calibrate equipment or check for signal noise. HDBlank
In video engineering, "blanking" is the period when a video signal is suppressed. This happens between frames (vertical) or lines (horizontal) to allow time for scanning mechanisms to reset or to carry metadata without displaying it on the screen. Common Contexts for "HDBlank" Are you trying to (like black bars) or
If using a video transmitter, access the register settings to enable "Auto-Blanking," which inserts black pixels outside the active area. HDBlank