The "legit" way to do that is straight up to model a cylinder and apply a texture, and you render it in 3d from the inside. That said, there is also very likely some math tricks you can do in a shader to render a quad that appears like that(though it is out of my league).
i would use a bunch of commands to copy some pixels around from surfaces to your background.
because it is only horizontal tube, you can copy the texture for the background manually line by line ...streched to the right amoount of space.
ok, i see the video above post solves it nicely, a shader is faster than copy of surfaces line by line... so i prefer shader! (but the principle behind it is same as i wanted to do)
Are you going out to the video or the Shader? I didn't watch the video, but either way, are you sure it's the method you are using and not your texture itself? If your texture it's too high definition, then the animation will also be too high definition by default.