A graphic that illustrates the different video resolutions.
A graphic that illustrates the different video resolutions.

What is HD, SD and UHD?

In 1941, a standard for television (SD or standard Def in today’s terms) in the USA was developed.  Known as NTSC, it dictated how many lines of resolution would define a television picture.  The old tube style (CRT) TV sets create a picture by drawing one horizontal line at a time.  The number chosen was 525.  Due to something known as “overscan, most TVs show only around 400 lines.  When computer displays came along, they broke the picture up into little blocks known as pixels.  The same was true for early panel displays.  The vertical height for a standard definition TV is 640 pixels, and can be either 480, or 720 pixels across for wide screen.  This is also the standard for DVD resolution.  A common misconception is that clients that ask for HD video, on a DVD disc.  Blu-Ray was developed specifically to support HD video.

 

What is HD?

When High Defintion was developed, there were two new standards, 720P and 1080i.  So named as they were 720 pixels X 1280 pixels, and 1920 X 1080 respectively.  More than four times the amount of picture information was possible in the new digital TV sets and projectors.  In recent years, we have seen more and more panel displays offering something called UHD or “Ultra High Definition”.  This is nearly the same as 4K used in movie theaters.  Once again, the amount of pixels was multiplied by about four times that of HD, and has the potential of up to eight times that of 1080i(P) HD.

How do I watch UHD?

You must of course have a display or projector capable of UHD.  Secondly, you must have content actually recorded in UHD.  In recent years, a few Blu Ray players offer this capability, assuming you have a UHD recorded disc.  These are easy enough to spot, as they bear the UHD logo.  Or, an internet connected device such as a Roku 4, and UHD content from sources like Netflix and Youtube.  Unfortunately, broadcast TV UHD is not quite ready for “prime time” as they say.