On over the air , cable and stream they have side bars for older shows but on DVD the picture is full screen.
My TV is set to wide screen and some movies are 16:9 aspect ratio. But full screen. Also newer shows are like this (Doctor Who 05 , Warehouse 13 and The Librarians for a few. Also Stargate SG1.) But when I watched on an analog TV the black bars are there. This could be HD if I'm not mistaken. Movies do retain the top and bottom bars however.Aspect ratio can get complicated, but in your scenario it sounds like an issue with your tv setting. If you are watching something filmed and encoded in 4:3 full screen, then you should have pillar box's on each side if you are watching with the correct setting on your tv. Odds are your tv's cable input is set correctly, but not your DVD player. Your tv is either stretching, zooming, or partially stretching your DVD input.