Understanding HDTV Formats and Components

This is a user-contributed article.

TV has evolved in the last 5 years and can be difficult to understand. There are many technologies out there in the marketplace that are worth being conscious of as you go and buy an HDTV. Today's HDTV's also come with a variety of resolutions. You may see 720p, 1080p, 1080i etc. We are going through a changing of the guard, and it's all gotten rather complicated when you want to purchase a replacement set!

The first generation of HDTV's had maximum resolution or lines of 1080i/720p but today's TVs have a maximum resolution of 1080p. When buying a TV you'll find these 1080p sets to be more expensive than those that have a maximum resolution of 1080i/720p. This is because these 'true' HD TV sets are not only newer but they can accommodate optimal resolution on blu-ray and HD-DVD players without having to scale the image. The i/p behind the number indicates whether the resolution is interlaced (an older method of scaling images that results in the image having to be put back together and the signal to degrade) or progressive scan (a newer, superior method that results in no signal degradation).

Because 1080i is interlace signal degradation means that signals broadcast in 1080i are only 10-20% cleaner than 720p signals which means these resolutions are similar. 1080p is true 1080 with no signal degradation. Though no network broadcasts 1080p because of the bandwidth required newer HD-DVD and Blu Ray technologies are all 1080p capable. This means if you buy a TV today with a max resolution of 720p/1080i you'll likely either be buying another in 2 years to get the most out of emerging technologies like blu-ray or HD-DVD or you won't realize the full HD experience.

Access to Full HDTV Signal Data

Access to 1080p is not only determined by whether your HDTV has the ability to access a 1080p signal directly, but also what format of 1080p your HDTV will accept. Almost all HDTVs today that accept a 1080p input signal directly can accept what is known as 1080p/60. 1080p/60 represents a 1080p signal at a rate of 60 frames-per-second. This is standard progressive scan with a resolution of 1920x1080.

However, with the advent of Blu-ray Disc and HD-DVD, a new variation of 1080p is being promoted and implemented: 1080p/24. The frame rate of standard 35mm film has a native frame rate of 24 frames per second. What 1080p/24 represents is the frame rate of standard 35mm film transferred directly from a source (such as a film on a Blu-ray or HD-DVD disc). This means that in order to display this image on an HDTV, the HDTV has to have the ability to display 1080p resolution at 24 frames per second.

Up to this point, most Blu-ray Disc and HD-DVD players read the 1080p/24 format information off of the disc and then reprocesses it so that it will be able to output the signal as 1080p/60, doing what is called a 3:2 pull down which results in some judder when viewed
but making it compatible with most 1080p input compatible HDTVs.

However, Pioneer (with others to follow) are starting to introduce Blu-ray players that output 1080p/24 off the disc directly and sends that signal unchanged to an HDTV. If the HDTV cannot process or display the 1080p/24 signal directly, the Blu-ray player will then reprocess the 1080p/24 signal to 1080i so that the HDTV will recognize the signal. If the HDTV is 1080p/60 capable, the HDTV will reprocess the 1080i signal to 1080p/60 in order to be able to display the image on the screen.

The Key To Good Signal: HDMI Connectors

Another emerging technology is the HDMI connection. HDMI is a digital connection technology which can accommodate high bandwidth across one cable. This means that using HDMI you can have one cable carrying your audio AND video to your HDTV or receiver. This reduces clutter behind the scenes. Because HDMI is digital a cleaner signal is sent to the TV resulting in a cleaner picture. Older technologies like DVI though digital didn't have the ability to carry audio and video. Component cables (Red,Green,Blue) were analog so signal degradation occurred because the digital signal had to be converted to analog and back to digital. HDMI can carry the highest resolution HD signal and still has room to spare for full HD audio.

In buying a TV consumers should be aware of the technologies out there. If a TV doesn't have at least 2 HDMI connections it should be viewed as obsolete as it will be so in a few short years. If a TV's resolution doesn't support 1080p it should also be viewed as obsolete