1080i and 1080p resolutions, what are the differences?


Mis à jour le 23 July 2021.

The format of high definition images is characterized by a resolution 1920 pixels wide and 1080 pixels high. HD resolution can be achieved via two different methods: interlaced (1080i) or progressive (1080p). Although both display methods have the same resolution, they each have advantages and disadvantages, resulting in unequal image quality. Which of these two HD resolutions should you choose? Here is how they work in detail.

The Optoma HD29He projector is a Full HD 1080p resolution HDR compatible model with a contrast ratio of 50,000:1 and a maximum brightness level of 3600 lumens. At under €700, it’s a must-have 1080p HD projector.

Understanding the differences between 1080p and 1080i

1080p and 1080i systems are both HD certified and therefore capable of displaying 1920 x 1080 pixel images. The difference between these two resolutions, however, is in the way the images are displayed. The letters “i” and “p” refer to the display mode used: 1080i refers to “interlaced” and 1080p to “progressive scan”.

1080i uses an interlaced display, whereas 1080p features progressive scan display.

How does a 1080i display work?

The interlaced display of the 1080i format displays each image twice. This is the display mode used by old cathode-ray tube televisions. It was developed to double the number of perceived images per second and improve the contrast of televisions with low scan rates. When the electron beams scanned the screen on old CRTs, there was a significant delay between the first pixel being displayed at the top of the screen and the last pixel at the bottom of the screen. As a result, there was a difference in luminosity between the top and the bottom of the screen and, consequently, a perceptible difference in contrast. Interlaced display was therefore created to display fewer lines simultaneously, thus ensuring better visual comfort. To do this, each image is split into two video fields: the first field contains only the odd lines of the image, and the second contains only the even lines. Each field represents half of the image’s lines. At a scan rate of 50Hz, half an image is obtained per scan, which corresponds to the European standard of 25 frames per second. This system takes advantage of persistence of vision and the brain’s ability to reconstruct the entire image.

How an interlaced display in 1080i works.

As the scan rate of televisions isn’t limited to 50Hz anymore, the interlaced format is no longer relevant. It is no longer used on modern televisions, whether they are LED TVs, UHD 4K TVs, OLED TVs or UHD 8K TVs, for example. However, this format is still used for DTTV. Why? Simply because this technology requires half the bandwidth and, consequently, a less demanding internet connection. Although the full size of the program remains the same, the information transmitted every second is two times smaller, as only half the image is broadcast.

The Sony VPL-HW65ES projector is a SXRD 1080p 3D array model. It is without a doubt the best 1080p HD projector on the market with a brightness of 1800 lumens and a contrast of 120,000:1.

How does a 1080p display work?

Like the 1080i format, 1080p features a resolution 1920 pixels wide and 1080 pixels high. It works differently, however, displaying the whole image at once. Each displayed image field therefore corresponds to an entire image. Progressive display is currently used by all modern computer screens and televisions, whether they are LED TVs, UHD 4K TVs, OLED TVs, UHD 8K TVs, etc.

The large LG OLED65B1 TV features a 65″ (164cm) 4K Ultra High Definition OLED display and the LG α7 Gen 4 Processor 4K video processor. It also features progressive image display.

Choosing between 1080i and 1080p formats

Due to its working principle, 1080p has more advantages than the 1080i format, starting with a superior perceived image quality. Even if an image has the same resolution in both 1080p and 1080i formats, and therefore the same number of pixels vertically and horizontally, the vertical resolution of an interlaced image seems to be almost 60% inferior. This is due to the fact that the even and odd lines of the image aren’t displayed simultaneously. Consequently, a video in a 1080i offers a very similar image quality to that of a file in 720p, meaning you cannot fully enjoy Full HD images.

A 1080p TV like the Sony KDL-43WF660B with a 108cm (42 inch) screen allows you to enjoy a wide range of HD content from DTT or VOD services (Netflix, Amazon Prime, Disney+, etc.).

Note: as mentioned earlier, DTTV programs are broadcast in 1080i in order to optimize bandwidth. A modern television must therefore carry out a deinterlacing process in order to reconstruct the original image from its two image fields. If this deinterlacing process is not performed correctly, it will generate artefacts and an aliasing effect in the image. Therefore, the importance of using a set-top box via internet or satellite and a Blu-ray player or a media player with a progressive scan-enabled video output is evident: the high-definition image produced by the player is ready to be displayed using a progressive scan and doesn’t risk being altered.

The Google ChromeCast Video is a great way to get the most out of a Full HD television.

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Bercé au son Cabasse, je suis passionné depuis toujours par la reproduction musicale et les nouvelles technologies hi-fi et home-cinéma. Perpétuel insatisfait, je suis en quête constante de nouvelles solutions pour redécouvrir mes musiques et films préférés dont la liste est très hétéroclite.


  1. Interlaced video is only an issue when de-interlacing is preformed; there is nothing inherently wrong with it on playback. Watching a DVD in 480i, and watching Blu-ray in 1080p, you wouldn’t know which is interlaced and which one’s progressive. And that’s one of the advantages of archiving images sourced from Blu-ray via computer: unlike DVD, said device can capture the image perfectly, with no weaving introduced- progressive on progressive.

  2. In the context of 2K and 4K, the “K” refers to the resolution of a digital display or image. “K” stands for “thousand,” so 2K refers to a resolution of approximately 2000 pixels across the horizontal axis, while 4K refers to a resolution of approximately 4000 pixels across the horizontal axis. These terms are commonly used to describe the quality of video and images, with higher K values indicating higher resolution and greater detail.

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