What is 1080i Video?

1080i is a high-definition television signal format. Among them, "1080" indicates that there are 1080 horizontal scan lines in the vertical direction, and "i" indicates that an interlaced scan video display method is used. During playback, it scans the singular vertical picture first, and then scans the double vertical picture, so it only needs half the bandwidth of 1080p. Its appearance has an important impact on the development of the television industry. At 15: 9 (closer to the screen golden ratio than 16: 9, the golden ratio is 1.618), the resolution is 1350x810.

1080i

1080i is a high-definition television signal format. Among them, "1080" indicates that there are 1080 horizontal scan lines in the vertical direction, and "i" indicates that an interlaced scan video display method is used. During playback, it scans the singular vertical picture first, and then scans the double vertical picture, so it only needs to

TV picture sharpness

D1 is 480i format, with the same definition as NTSC analog TV, 525 vertical scanning lines, 483 visible vertical scanning lines, 4: 3 or 16: 9, interlaced / 60Hz, line frequency is 15.25KHz.

D2 is 480P format, same specifications as progressive scan DVD, 525 vertical scan lines, 480 visible vertical scan lines, 4: 3 or 16: 9, resolution is 640 × 480, progressive / 60Hz, line frequency is 31.5 KHz.

D3 is a 1080i format, which is a standard digital TV display mode, with 1125 vertical scanning lines, 1080 visible vertical scanning lines, 16: 9, resolution of 1920 × 1080, interlaced / 60Hz, and line frequency of 33.75KHz.

D4 is a 720p format, which is a standard digital TV display mode, with 750 vertical scanning lines, 720 visible vertical scanning lines, 16: 9, resolution of 1280 × 720, progressive / 60Hz, and line frequency of 45KHz.

D5 is

1080i and 1080p are high-definition standard formats determined by the American Society of Motion Picture and Television Engineers. Among them, 1080p is known as the current top-level display format of digital televisions. This format of televisions can achieve a resolution of 1920 × 1080 under progressive scanning. Limited by the storage medium (a 1080p movie requires more than 10GB of storage space). Currently, most 1080p movies are distributed in Blu-ray mode. With the popularization of Blu-ray players and HD players, the download of HD movies on the Internet has gradually increased. Kmplayer With the introduction of software such as, potplayer, the increase of PowerDVD, WinDV high-definition playback functions, and the launch of domestic high-definition televisions, the concept of high-definition is increasingly recognized by many people, and even many people have become "high-definition control."

When it comes to HDTV, many people think it is very simple, not just 720P, 1080i, but at most 1080P. But many people do not know that there is no difference between 1080i and 1080P for flat-screen TVs. Few people know that 720P is only a standard used by several American television stations. Many high-definition concepts are passed on, and even 720P, 1080i, and 1080P are incorrect. Let's start with the concepts of 720P, 1080i and 1080P, and correct some misunderstandings about HD and understand the true nature of HD.

In 720i and 1080i, i is interlace, which means interlaced scanning; P is Progressive, which means progressive scanning. To clarify these two terms, we must also start with analog CRT TVs. The traditional CRT TVs work by scanning electron beams on the screen and then emitting light to display images. During the transmission of TV signals, due to the limitation of bandwidth, only interlaced signals can be transmitted to save bandwidth. Take an NTSC TV as an example. When working, a 525-line image is divided into two fields to scan. The first field is called an odd field, and only the odd lines are scanned (scanning 1, 3, 5 ... lines in sequence), and the second The field (even field) only scans the even number of lines (scanning 2, 4, 6, ... in order), and the number of lines of the original image scanning is completed by two field scanning. Because the human eye has a visual persistence effect, it still looks when it is in the eye. It is a complete image. This is interlaced scanning. NTSC program has a total of 525 lines of scanning lines, 60 fields per second, expressed as 60i or 525i. If it is progressive scanning, it is called 60P or 525P. PAL program is 625 lines, 50 images per second, expressed as 50i or 625i, progressive is called 50P or 625P. Remember, this is for

It not only represents the scanning format of the CRT TV, but also the format of the images captured by the camera. Because the television system was originally an interlaced scanning system, the cameras corresponding to NTSC and PAL TV programs are also interlaced, which means that all NTSC / PAL programs shot by TV cameras are interlaced. The signals are represented as 525 / 60i and 625 / 50i, respectively. Remember, this is for TV cameras.

For analog TV images, it is expressed in scanning lines, PAL is represented as 625 / 50i; NTSC is represented as 525 / 60i. For digital signals, it is expressed in pixels or resolution. For example, PAL programs have a resolution of 720 * 576, progressive can be expressed as 576P, and the interval is 576i. NTSC resolution is 720 * 480, line by line is 480P, line by line is 480i. Remember, this is for TV images.

That said, it s a bit like a tongue twister, and it s a little bit daunting, but the concept of high-definition 720P, 1080i, and 1080P is necessary. Having said that, everyone should remember that for high-definition, 720P, 1080i, and 1080P The concept of TV must be understood from three aspects: television, camera and image format. Television, camera and image format are different and related concepts.

HDTV, also called HDTV, according to CCIR

Considering the technical limitations of the CRT TV at that time, and in order to take care of the computer industry's display as a progressive scanning system, the CRT uses a progressive scanning system when displaying 1280 * 720 images, referred to as 720P for short. When displaying 1920 * 1080 images, an interlaced system is used, referred to as 1080i. According to the technology at the time, it was not possible to produce 1080P CRT TVs, which appeared only in the 21st century. This is where the concepts of 720P, 1080i and 1080P came from.

However, CRT has been eliminated and flat-screen TVs have been replaced. For LCD and plasma TVs, they are fixed-pixel display devices that do not need to be scanned when displaying images, and each pixel can be considered to emit light at the same time. If it is necessary to associate with the concept of interlaced and progressive, LCD and large Most plasma TVs are progressively scanned. So does it mean that 720P, 1080i and 1080P can be cancelled? The answer is no, because there is still a camera format.

Although high-definition cameras are digital, the scanning method is inherited from analog cameras. Traditional analog cameras are all interlaced, while high-definition cameras, while retaining the interlaced scanning format, have also added a progressive scanning format.

HD cameras not only keep interlaced and progressive, but also keep the difference between PAL 50Hz and NTSC 60Hz. Although HD is no longer different from PAL and NTSC, in the traditional NTSC areas such as the United States, Japan and South Korea, The 60Hz frequency system is still retained, while China, Australia, and Europe still retain the 50Hz system. High-definition programs are all digital signals, so it only needs to be expressed in resolution. HDTV is divided into two types of interlaced scanning and progressive scanning when shooting, and the frame rate (the number of progressive images displayed per second) or the field frequency (interlaced images displayed per second) are also different.

1280 * 720 has 5 frame rates, which are 60P, 50P, 30P, 25P, 24P, which can be abbreviated as 720P, and can also be expressed as 720 / 60P (used by American ABC TV station); 720 / 50P; 720 / 30P, 720 / 24P (FOX station); 720 / 25P. Among them, 720 / 50P and 720 / 25P did not originally exist. Later, when Germany chose high-definition image standards, it had intentionally selected a 720P system. Considering that Germany has traditionally been a 50Hz system country, some manufacturers have introduced support for 720 / 50P and 720 / 25P Cameras, but basically no country chooses this standard, at most it is an issue.

The situation of 1920 * 1080 is more complicated. The interlaced representation is 1080i and the progressive representation is 1080P. In the United States and Japan, the field frequency is 60Hz, which can be expressed as 1080 / 60i, and in China, Europe, and Australia, it is 1080 / 50i. Both formats can be called 1080i. The matter did not end there. In order to facilitate the production and exchange of high-definition programs, the 1080 / 24P standard has been adopted worldwide. This standard is also used as the standard for digital movie cameras. The famous "Star Wars Prequel" is used Many high-definition TV dramas shot by 1080 / 24P cameras, such as "House Gate" are also 1080 / 24P.

But this is still not the full connotation of 1080P. For flat-panel TVs, in fact, it can be considered that there is no difference between 1080i and 1080P, because the current image processing circuit technology develops very fast, the operation speed is very fast, the processing capacity is very strong, and both have double-line technology . The so-called scaling technology is to process interlaced 1080i images into progressive 1080P images, which can perfectly process 1080 / 50i into 1080 / 50P and 1080 / 60i into 1080 / 60P, including programs in 1080 / 24P. It can be handled very easily as 1080 / 50P or 1080 / 60P. And any flat-panel TV has this kind of circuit, a slightly high-end flat-panel TV has a good processing effect.

Having said that, it seems that the format of the TV has not been mentioned yet. The format of TVs is more complicated. The resolution of LCD and plasma TVs is different. Different countries and regions have different opinions about the resolution of LCDs and plasmas.

The high-definition television set by the American Consumer Electronics Association ECA and the European Telecommunications and Appliance Industry Federation EICTA must reach a resolution of 1280 * 720 or higher. Follow April 5

But plasma can be lively. The 42-inch plasma has the following four resolutions: 852 * 480, 1024 * 768, 1024 * 1024, and 1024 * 1080, all of which do not meet the requirements of the high-definition national standard. Only 50-inch plasma meets the HD national standard. To further complicate matters, the two plasmas, 1024 * 1024 and 1024 * 1080, are not displayed progressively, but alternately emit light alternately. The above said that "the LCD and most plasma TVs can be considered to be progressively scanned." For this reason. But you don't need to worry about this problem, even the interlaced display has little effect on the viewing effect.

Among the flat-panel TVs, especially some plasma TVs that fail to meet the high-definition national standard requirements are still stated in the promotional materials as 1080P. This 1080P has a different interpretation from the 1080P we said above. Taking Panasonic 42PA60C as an example, the physical resolution is only 852 * 480, which does not meet the high-definition national standard requirements. Panasonic's 1080P is that the 42PA60C can receive 1920 * 1080i signals and can be processed into 1920 * 1080P format. However, the resolution of the 42PA60C is only 852 * 480, and it cannot display 1920 * 1080 pixels completely. Therefore, the resolution of the high-definition image is first reduced to 852 * 480 and displayed on the 42PA60C. This 1080P is not even high-definition, it is precisely compatible with 1080P.

For high-definition programs, the concepts of 720P, 1080i, and 1080P have no practical meaning anymore. It is sufficient to use 720 for 1280 * 720 and 1080 for 1920 * 1080, because even for 1080i images, flat-screen TVs can be processed into 1080P. of. For flat-screen TVs, 720P, 1080i, and 1080P are even more meaningless. Flat-screen TVs can all be considered progressive, and the resolution is determined by the resolution. According to the HD national standard requirements, it must reach at least 1280 * 720, of course, 1920 * 1080. The resolution is the best, but it has nothing to do with 720P, 1080i and 1080P. The only thing that still needs 720P, 1080i, and 1080P concepts is the HD camera, but for TV viewers, we only need to watch the program. As for the format of the camera, the program does not affect the viewing effect.