A High Definition TV also known as a 720p display, is the current standard for Entry Level Televisions, HD or 720p refers to a display with a resolution of 1280x720 pixels. The higher the resolution or the higher the number of pixels, the sharper the image quality is.
Full High Definition Televisions also referred to as 1080p displays, are a display with a resolution of 1920x1080, that is just over 2 Million pixels and more than twice that of HD or 720p. Thus giving a sharper image quality.
Ultra High Definition Televisions or UHD TVs are also referred to as 4K Television, the 4K name is derived from a horizontal resolution of approximately 4,000 Pixels, this can sometimes be 3840x2160 or 4096 x 2160, this gives a UHD Television a resolution of anywhere from 8.2Million to 8.8Million Pixels, Resulting in an extremely fine image allowing bigger screens to be viewed from closer distances without images appearing distorted.
DVD Players allow you to play a huge catalogue of Movies, Documentaries and much more on your TV, DVD Players are somewhat backward compatible in that they will play CDs too.
When choosing a DVD Player consider what you need to connect it to and what you wish to get out of it, Some DVD Players Are PVRs (Personal Video Recorder) too, allowing you to record to either a HDD within them or even other forms of media such as USB
Blu-ray Players are are similar to DVD Players and PVRs in that they play a disc, in this instance naturally a Bluray Disc, capable of holding a lot more information and data than a DVD or CD can, this allows higher resolution videos, more defined audio for your surround system and even interactive menus. BluRay Players are also available as PVR or DVR as well adding to your connectivity options in decluttering your set up.