NTSC TV-out, output safe for DVR?

using the library from Github:

wired exactly as described here:

Using a Mega2560. I have not installed the 75 Ohm resistor between Vid and Ground , as it was listed as optional, and I didn’t happen to have one on hand.

I have tested the circuit and library on a TV, and it works.

My question is this. I intend to use this for a status output for my Security Alarm project. I have an open channel on my security camera DVR, and before I plug it in, how safe is the output from the Arduino to plug into a video in port? in other words, what is the normal line video voltage levels? my DVR doesn’t happen to say.

My research says line video is about 1 volt. now, I haven’t scoped the output of the circuit yet as I have not yet finished my morning cup of coffee. but it appears, with my limited understanding of analog, that the output would be near 5V without the 75 Ohm pull-down.
with the pull-down, it becomes a voltage divider, and the calculated volts are below 1V.

I will likely order up some 75 Ohm resistors, but I want to be absolutely sure it is safe before I try plugging into my DVR in the meantime.

Thanks in advance for any help.