Creating a Pipe for Ethernet and Video Cables
You probably will not be placing a larger diameter pipe horizontally in a stud wall for 10 or more feet because of the fact that you would be sacrificing much of the strength of the wall studs to do so. If there is crawl/access space below the floor or above the ceiling the obvious choice would be to route the pipe in those spaces making sure to use sweep corners so that the bends are are easy to pull cable through. PVC pipe, which is available in a range of sizes, is likely going to be easiest for you to work with.

If the cable route is going to have to be routed within the room space then you have a number of options and things to consider:


Just placing a round pipe against a wall can be somewhat inefficient because it sticks out into the room farther than some other options.
There are commercially available cable raceways that you can purchase that might be just the ticket for you. Variable sizes exist and the top typically opens or pops off to allow access to the inside. Some raceways can also be painted to match the room colors.
There is a technique to install cables behind a larger cove molding that would be installed at the upper corner between the wall and ceiling. You could combine the cable installation with trim in the room. Be aware that this choice can be hardest to install cables later after the trim is already in place.
I have used a scheme in the past to hide wiring along a wall behind a PVC pipe that was split in half lengthwise. It took a special fixture made up of boards and 2x4s to hold the pipe safely and securely so that I could use a circular saw to cut the pipe. The half pipe was painted after it was attached to the wall using a narrow strapping material.