What is Aspect Ratio?

Aspect ratio is the shape of the picture — 16:9 for TVs, wider ratios for many films (hence the black bars, which are part of the film, not a fault).

If a channel looks stretched or characters look wide, the TV's aspect/picture-size setting is on Zoom or Stretch — set it to "Just Scan", "Original" or 16:9. Never use stretch modes to remove cinematic bars; you're cropping the movie.