YouTube. They're always jacking with it. They only buffer so much of a video now instead of the whole thing. Sometimes the buffer can't get far enough ahead. Could be uverse. Do a free speed test.
Even with my upload speed it still takes awhile to upload a 10min video to YT for some reason so it has to be on their end. With your speeds it will either not upload at all or take HOURS to upload a 10+min vid. Sending you a PM