Industry standard is the Ridgid video.
A sewer line is rarely filled. The video camera snakes have bright LED lights on the end. If you get to a point where you can't see anything, you've found the blockage, right?
Apparently, no one has used one of these. On the camera end, they have nozzles that take high pressure water and spray it onto the walls of the pipe, like a power sprayer. This flushes goo ahead of the camera, or just cleans out spots the camera wants to get a better look. If the pipes are installed correctly, the poop runs downhill, and there's a clear field of vision. I watched the guy do mine, and I was amazed at the small amount of fluid in the line. Mine had a root which they snipped. But at the same time, they will jet the whole line, cleaning off the pipe walls, and leaving you with a whole lot better system. Of course, they don't do it cheap or for free, as these machines cost quite a bit, and their time is worth something, what with the truck, and the insurance, and the licenses, and all that.