There are some websites that are well established in this industry but their pay out are not encouraging and that in turn is killing the get paid to view video industry.
That's because the concept is flawed, paying someone to view an add is a concept that's been tried and failed so many times in the past, if people are getting an incentive to look at an add they are doing it for money and don't even pay attention to it. Even if the user wanted to pay attention to the add there is only so many adds people can watch purposely and still have the information sink in.
You are absolutely right
kalodu people that view such videos only have but little interest in the actual advertisement which is what the get paid to view video website is paying for, some might not even watch at all but check to see if the video have ended then click next, enter captcha and the likes.
@ OP, You should be able to understand some facts about the video view industry from our discussion.
Good luck.
It would be better if theirs no captcha at the end of the video since it can be hassle to the people who do the watching task and that would not be a decent doings if he only pays low. But if OP have a great Bounty for it then its decent to implement that captcha so that he can make sure that people finished to watch the videos and decent to get the bounty from it. And OP should do some unique implementations,tactics and promotion so that his site will get some video watchers.