Right Turn on Red is allowed in all 50 states and all provinces and territories of Canada. The cities of New York and Montreal, however, specifically disallow it unless there is an explicit sign allowing it. In all other places it is allowed unless there is a sign disallowing it.
The rules for "Right Turn on Red" are the following:
- The car must come to a complete stop.
- The stop must be behind the broad white line or any sign explicitly saying "Stop Here on Red".
A complete stop means the wheels must stop moving. Braking and slowing down even to 1 mph isn't the same as stopping. Although there is no fixed amount of time you must be stopped for, many people use 3 seconds as a rule of thumb to be sure.
The stop must happen, no matter how much or how little traffic there is, before you can proceed with the right turn.
In your case, your video clearly shows that you didn't come to a complete stop, and you were well past the white line when you slowed to your slowest. Stopping past the line is much more likely to get you a ticket from a Red Light Camera than from an actual police officer.
Here's some local discussion of Red Light cameras in Delaware:
And here's a Google streetmap image showing that there is an explicit "Stop Here on Red" sign at the intersection: