The HDMI port on your DVD player is probably just output

DVD *players* don’t have an imput – they’re just output. So what you were planning wouldn’t work. If you had a DVD burner, it might have an input, but probably only coax.
Very old TVs would only have Coax(cable) or Composite. Those you couldn’t connect to your computer. Slightly less old TVs might have a VGA or DVI inputs. Those you could connect using your normal computer VGA or DVI port. TVs that are newer still would probably have an HDMI input, which could be used with an HDMI cable.