What is High Definition Television (HDTV)?
High Definition Television (or HDTV) refers to an image having a resolution substantially higher than traditional television systems, eg CRT TV (576 lines). High definition (HD) is at the top of the digital television (DTV) spectrum.
(The Advanced Television Systems Committee (ATSC) divided HD into three categories listed in two different forms – ‘number of lines + type of scan’ or ‘number of pixels’ (vertical by horizontal).)
A Breakdown of the HD formats :
– 720p ( 720×1280 – 720 lines, progressive scanned)
– 1080i (1080×1920 – 1,080 lines, interlaced scanned)
– 1080p (1080×1920 – 1,080 lines, progressive scanned)
The number of lines/pixels and type of scan matters because more lines/pixels and faster scan equals a better picture.
High Definition vs Full High Definition
The Line count is below 1080 going up the screen but more then 576 lines. Both Interlaced and Progressive Scans are possible for HD images.
Full High Definition
The line count is 1080 going up the screen.
An example of the picture you may get with each signal.
There are 5 requirements to enjoy the HDTV experience:
1. A UHF aerial
2. An HD capable digital terrestrial receiver
3. An HD capable Television (at least 1280 x 720 resolution)
4. An HDCP compliant input
5. A HDMI cable
Differences between Composite, S-video, Component, and other sources
This is the worst possible connection you can use. If your set supports S-video, please use it. Composite basically ties every signal into one cable and throws it at the set.
A huge upgrade from Composite. Basically the colour separation is done within the same cable, but has its own dedicated line. Every small wire that connects to the S-video female port carries its own signal for richer colour separation and less signal degradation.
If you have a set that has component but does not support progressive scan, the improvement is minimal. You may as well stay with S-video. If you have a set that supports progressive scan however, switch to Component and start using 480p.
A common standard for European AV connections. Capable of carrying high resolution input and output signals through a single cable. A SCART connection typically has a 21–pin connector and is most commonly used in New Zealand as a link between digital satellite set-top boxes and compatible televisions or DVD recorders.
A new digital connection that can carry the audio and the video in the same connection. Purely digital. For standard length cables the cost does not show any major change in quality. There is only a change in quality when the cables are more then 3 metres.
Other terminology to know
HDCP – High Definition Content Protection
Used to encrypt the signal from the source to the receiver. Intended to protect content not copy protection.
HDMI – High Definition Multimedia Interface
The High-Definition Multimedia (HDMI) is a connection system for digital video and audio that transmits signals, without deterioration, to achieve very high audio and video quality. HDMI carries a full 1080p signal to connect digital sources such as set-top boxes, Blue-Ray Disc players, personal computers, video game consoles, and AV receivers to compatible digital audio devices, video monitors, and digital televisions.
HDTV – High-Definition Television
HDTV offers wider pictures with greater detail and the clarity of motion pictures and has a significantly higher resolution than traditional formats.
This indicates that the set is capable of displaying a high-definition picture that is provided from some tuning device or set-box that is external to the set itself.
Interlacing is how standard TV is broadcast with the picture information sent in two parts, the odd lines first, then the even. With this being done 50 times a second, the human eye blends the lines together to form one image.
Progressive scan displays the entire video frame in a single sweep at 50/60 frames per second. You do need an HDTV ready TV for progressive scan viewing. Progressive-scan picture quality is more film-like, with more fine detail and less flicker.
The smallest element of a picture on a TV. A single dot that can be changed in colour or brightness to according to the portion of the whole picture.
A small monitor may have a resolution of 640 x 480, which means that there are 640 pixels horizontally across the screen and 480 pixels vertically. Some other common monitor resolutions are 800 x 600, 1024 x 763, 1280 x 1024, 1366 x 768 and 1920 x 1080.