Why are NTSC and PAL still important to HDTV?

Even with the advent and ubiquity of digital TV, HDTV broadcast capabilities, and source devices (such as Blu-ray disc players and streaming media devices), old barriers to standards The popular video has not been removed yet. This article explains why the NTSC and PAL standards are still important.

Note : This information applies to TVs from many manufacturers, such as LG, Samsung, Panasonic, Sony, and Vizio.

Frame rate

Although video is now primarily digital, the frame rates used in analog video systems are still incorporated into digital TV and HDTV standards. In video (analog, HD and 4K Ultra HD), as well as in movies, images are viewed on the screen as complete frames. However, there are differences in the way television stations broadcast the frames, transmitted through streaming media devices or physical media and displayed on screens.

Lines and pixels (pixels)

Live streamed or recorded video images consist of scan lines or rows of pixels. In movies, the entire image is displayed at once. In contrast, lines or rows of pixels in a video image display across the entire screen, starting at the top of the screen and moving to the bottom. These rows display in interlaced or progressive format.

Interlaced scanning divides lines into two fields. The odd-numbered lines or rows of pixels are displayed first, and the even-numbered lines or rows of pixels are displayed next, creating a complete frame.

Progressive scanning displays rows sequentially instead of transmitting rows as two fields instead. This means that both odd-numbered and even-numbered lines or rows of pixels are displayed in numerical order.

The number of vertical lines or rows of pixels determines image detail. The more lines in an image, the more detailed the image. The number of lines is fixed in a system.

NTSC and PAL

The two main analog video systems are NTSC and PAL.

NTSC consists of 525 lines or rows of pixels, 60 fields at 30 frames per second, at a 60Hz system to transmit and display video images. Each frame is transmitted in two fields of 262 lines/rows of interlaced display pixels. The two fields are combined, so each frame displays 525 lines/rows of pixels. NTSC is the official analog video standard in the United States, Canada, Mexico, some Central and South American regions, Japan, Taiwan, and Korea.

PAL is the world's dominant format for television broadcasting and analog video display. It consists of 625 pixel lines/rows, 50 fields at 25 frames per second, 50Hz system. Like NTSC, the signal is interleaved into two fields, each consisting of 312 lines/rows of pixels. Because it displays fewer frames (25) per second, you may sometimes notice a bit of flicker in the image, just like on slide film. However, PAL has slightly higher resolution and better color stability than NTSC. Countries that use the PAL system include the UK, Germany, Spain, Portugal, Italy, China, India, Australia, much of Africa and the Middle East.

NTSC/PAL and DigitalTV/HDTV aspect ratio

Although the increase in resolution of digital, high-definition broadcast, and video software content standards is a step forward when comparing HDTV to analog NTSC and PAL standards, frame rate is the basis common foundation of both systems.

In countries adopting NTSC-based standards, 30 separate frames are displayed every second (i.e. one complete frame every 1/30th of a second). In countries adopting a PAL-based standard, 25 separate frames are displayed every second (i.e., a complete frame is displayed every 1/5 of a second). These frames are displayed using interlaced scanning (480i or 1080i) or progressive scanning (480p, 720p or 1080p).

In the case of digital TV and HDTV evolved from NTSC, if frames transmit as interlaced images (1080i), each frame consists of two fields and each complete frame displays every 30 seconds, using uses 30 frames per second based on NTSC. If the frame is transmitted in progressive scan format (720p or 1080p), it will display twice every 30 seconds.

HDTV and digital TV frame rates are based on PAL

In the case of digital TV and HDTV that evolved from PAL, if frames are transmitted as interlaced images (1080i), each frame consists of two fields and a complete frame is displayed every 25 seconds, using PAL-based 25 frames per second.

If the transmitted frame is in progressive scan format (720p or 1080p), it will be displayed twice every 25 seconds.

Conclude

Digital TV, HDTV and Ultra HD, while a huge advance on what you see on a TV or projector screen, are still rooted in analog video standards that are more than 65 years old.

As a result, there are differences in the digital and HDTV standards being used around the world, placing limits on video standards worldwide.

Additionally, as the transition continues toward digital and HD-only transmission, many people still have NTSC- and PAL-based video playback devices, such as VCRs, analog camcorders, and DVD players that do not have HDMI capabilities. Plugs into HDTV (and 4K Ultra HD TV).

Even with formats like Blu-ray, there are cases where the main movie or video content may be in HD, and some of the video extras may be in standard definition NTSC or PAL. DVDs are still created in NTSC or PAL format.

While 4K content is now widely available through streaming and Ultra HD Blu-ray Disc, 4K TV broadcast standards are still in the early stages of implementation. 4K TVs must support analog video formats as long as analog video playback devices are being used.

Broadcasting and streaming in 8K resolution is also now a thing, although the high price tag keeps it from being widely adopted.

Ultimately, you may no longer be using analog video devices, but others may still be.