So why do you sometimes get black bars on each side of the picture?
Footage produced in 4:3 and presented on a widescreen TV has black bars at the sides to fill the screen.
To see the correct picture size and shape there are two things you need to do:
- tell your set top box or PVR that it's attached to a 16:9 TV (look in the digital receiver set-up menu), and
- set the TV 'aspect ratio' with your TV remote to 16:9 (sometimes called widescreen or simply, wide mode).