HD-DVD was officially discontinued on February 19, 2008. Today all DVD Players are Standard Definition. Only Blu-Ray Players play HD content on Blu-ray discs.
As it is implemented, DVD is not a high-definition format. DVD players typically output video in either standard NTSC 480i (720×480 pixels in an interlaced scan format), with progressive scan DVD players capable of outputting DVD video in 480p (720×480 pixels displayed in a progressively scanned format).
DVD is only half the resolution of HDTV