Everything About SD, HD, and 4K/8K TVs

In Resource Center
Still confused about SD, HD and 4K/8K resolutions? How do they relate to each other and where the numbers come from? This blog article will hopefully make it a lot clearer. It’s not rocket science but sometimes the techy world of digital media can be a bit complex.

Terms You Should Know

Display Resolution

This refers to the number of pixels the display has, measured width by height. For example, 1920x1080, is the display resolution of some television sets. You will see display resolutions with video cameras, cell phones, pc monitor displays, and televisions -- basically anything with a video display.

You've most likely seen 720p, 1080p, 1080i, 4K(2160p) and 8K (4320p) movies and/or television sets for sale at the store. These numbers come from display resolution's height, specifically the "height". P stands for progressive, we'll talk about that next.

The general rule of thumb is the more pixels you have, the more detailed the image will be.

Aspect Ratio

The aspect ratio is the the proportional relation between the width × height of the display/video/image. Most often, you will find the aspect ratio in videos expressed as 16:9 (1.3:1) or 4:3 (1.33:1).

16:9 is the most common ratio used today for HD (high definition) television. Think Netflix, Hulu, Movie Theatres, etc. It's more rectangular in shape.

4.3 on the other hand, is the original video SD (Standard) format of the 20th century, and was most common pre-2000's. When wide screen TVs become more common in the 2000's, 16:9 became more mainstream. 4:3 is more square in shape.

Interlaced & Progressive

 We spoke about the display resolution above, and some include letters such as "p" or "i" after them. These refer to interlaced or progressive, a method in which the video has been recorded/displayed.

Interlaced is when camera's capture and display images by alternative lines of video, separated in odds and evens. It works so fast the human eye cannot discern and always looks complete. Interlacing was common in SD television sets.

Other devices use progressive scanning, which is recording/displaying one line of pixels after the other, sequentially and without alternating. Progressive is more common  in HD TV sets and provides a more fluid experience. 

Standard Definition (SD, SDTV)

Standard Definition TV

Standard definition is a specification for video and film before HD came out in the early 2000's. This includes film, TVs, and movie theatres from the early to late 20th century. SDTV's commonly use a 4.3 aspect ratio and 480i and 576i display resolution. At the time, interlace scanning was the primary way video was displayed. Interlace scanning was used to reduce flicker and provided twice the refresh rate at lower video bandwidths. 

  • 480i or 576i
  • 720x480 or 720×576 (full frame)
  • 4:3 or 1.33:1

High Definition (HD, HDTV)

High Definition TV Set (HD)

High definition is the most common format of all movies, film, and television sets today. They come in many different variants, including (but not limited to):

  • 480p / 640x480
  • 720p / 1280 x 720
  • 1080p / 1920 x 1080
  • Aspect Ratio: 16:9

The majority of HDTV sets come with progressive scan, however some may be available with interlaced scanning (720i, 1080i). 

Ultra HD (UHDTV, UHD, Super Hi-Vision)

A new term you may have also seen or heard of is Ultra HD. UHDTV is the new digital format of the latest TV technology and the successor to HDTV. Here are common UHDTV formats:

  • 2160p (4K) / 3840 × 2160
  • 4320p (8K) / 7680 × 4320 
  • Most commonly display in 16:9 aspect ratio

Is there any reason to get an 8K TV today?

We don't recommend it. There's not a lot of high-resolution content to play on your 8K TV, it's more about bragging rights and potentially future-proofing your TV purchase. We personally recommend that you stick with a 4K today, because newer technology  will come out and prices will go down once more 8K content becomes available.


There's a lot of information out there, but this guide has enough information to help you make informed decisions and understand everything about SD, HD, and UHD. Here's a quick overview.

Standard Definition Television (SDTV)
  • Timeframe: Pre- 2000's
  • 480i, 720i
  • 4:3
High Definition TV (HDTV)
  • Timeframe: 2000+
  • 480p, 720p, 1080p
  • 16:9
Ultra High Definition TV (UHDTV)
  • Timeframe: 2012+
  • 4K, 8K
  • 16:9