Although specifically not related to a blue ray problem, I was fooling with longer USB cables between my computer and some outside devices. IN particular, one outside device had its own cable attached about 3 feet long. Everything worked fine on that cable. With a 15 foot usb cable added to it, I began to get video dropouts since it was carrying video info. At 30 feet, I had no video signal at all. I even hooked up a separate 6 ft. extension USB cable of a different make and the video dropouts appeared. So this shows that there is a certain amount of signal that can be carried by long cables. I do not think there are amplifiers on the market for what I was doing but that was the first thing that came to my mind.