1080i vs 1080p – Difference and Comparison

What is 1080i?

When CRT technology was innovated for screens, CRT TV and monitors became popular. In CRT screens, horizontal lines are present.

Electron beam paints those horizontal lines to show a picture. But it was seen that when it paints all lines from beginning to end, the luminosity of top part starts to fade soon.

Therefore, the concept of interlaced scan was introduced. So in this scan, the CRT device paints all of the odd number of lines first and then paints the even numbered. In this way, the screen looks like completely brightened and clear. In this method, the image prints twice on screen. 1080i is able to display an image of resolution 1920 pixel long and 1080 pixels wide.

This became helpful, because our mind tries to complete each image it sees. In old TV’s you can find those horizontal lines. But it also cause a problem on screen, i.e., flicker.

The number of time, machine can paint the whole screen in one second is called refresh rate. In low refresh rate, the screen flickers a lot, which ruins the mood of screen watcher. It is the biggest drawback of interlaced scan. It also decreases the quality by two times.

The refresh rate of 50hz is most popular in CRT screens and it resembles with the European standard of 25 frames per second.  In this refresh rate, flicker of screen images decreases a lot. But as the TV technology went ahead, the scan rate increased and the interlaced scan became irrelevant.

But still it is used with DTTV because it has to transmit data with low internet connection speed. It also needs half of the bandwidth of data. So interlaced scan works good for it. By the way the information or program transfers completely, but processed twice as in 1080i format.

What is 1080p?

So after CRT, new technologies for screens came in market, like LED, LCD, UHD etc. This devices does not have electron beams but they uses pixels. Pixels are very small in size and are more powerful way to depict pictures on screens.

In these screen, the concept of interlaced scan was removed and progressive scan was introduced. All horizontal line of pixels are painted consecutively. Therefore it also gives a very high quality.

As we shifted to progressive scans, the refresh rate of interlaced scan was transformed into frame rate. Because in this scan, the number of frames of data screen can load in one second is calculated. 60hz is the most popular screen frame rate.

Nowadays, we use every device which have screen, most of them uses progressive scan. 1080 denotes to the horizontal number of lines. 1920 vertical lines are found with 1080 horizontal lines. Even it is a much better choice than 1080i format because the quality of image remains the same.

Difference Between 1080i and 1080p

1. 1080i is used for interlaced scan type screens and 1080p is used for progressive scan type screens.
2. Interlaced scans were popular in CRT based screens and progressive scans are popular in pixels based screens.
3. In interlaced scan, first odd and then even horizontal lines were painted. Whereas in progressive scan all lines are painted continuously.
4. In interlaced scan, problem of flicker is faced a lot. Relatively, no such problem were seen in progressive scan.
5. In interlaced scan, speed of screen updating is calculated by refresh rate. In progressive scan, it was shifted to frame rate.
6. Interlaced scan gives less quality as compared to progressive scan.

Comparison Between 1080i and 1080p

Reference

1. https://ieeexplore.ieee.org/abstract/document/7991102/