I don't understand what you mean regarding "video testing companies" but know most good plumbing companies have them available to inspect most all plumbing lines.
As long as there is a way to get into the pipe the camera can inspect from 2"-6" very easily. Anything larger requires a very expensive truck mounted rig with motorized wheels.
It varies greatly. Depending on how many offsets are in the pipe and how durable the cable is. A non motorized camera can inspect up to 200' of straight 4" pipe. On average the farthest I can go is about 120'.
The motorized cameras generally have 400' of cable but cannot take turns greater than 45 degrees.
question about video testing
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