High-definition video or HDTV refers to a video system of higher resolution than standard-definition Television (SDTV), that is, NTSC (National Television System Committee) and PAL (phase-alternating line).High-definition video requires a high-definition television or computer monitor in order to be viewed.
HDTV has approximately twice the resolution of SDTV, thus allowing much more detail to be shown as compared to analog television or regular DVD. MPEG-2 is most commonly used as the compression codec for digital HDTV broadcasts.
High-definition video generally has an aspect ratio (This refers to the ratio of the height of the screen to the width of the screen) of 16:9, while Standard-definition television (SDTV) has a 4:3 (1.33:1) aspect ratio. It also squeezes the bandwidth required for digital data in order to form the image on the display screen clearer than SDTV (Standard Definition TV)
A High Definition image can range from a large image of 1920×1080 pixels and can also be compressed down in a lot of different screen sizes all the way down to a video iPod screen of 320×240. In addition, the largest size image contains approximately six times the pixel resolution of a Standard Definition video. This means that the quality, sharpness and the color are exceptional compared to Standard Definition.
There are High Definition disks like HD-DVD and Blue Ray. Players for each are available.HD content can be delivered on DVD for computer playback and can be viewed on HDTV.HDTV and standard definition televisions (SDTV) are the two categories of display formats for digital television (DTV) transmissions.
High Definition is a set of standards for higher resolution display set by the Advanced Televisions Standards Committee (ATSC).It is basically a type of digital television which allows markable improvements in both picture and sound quality as compared to the earlier analog television formats like NTSC. Digital television can be delivered in two basic formats standard analog definition SDTV or high definition HDTV. HDTV is a type of Digital Television (DTV) broadcast, and is considered to be the best quality DTV format available.
In HDTV,1080i and 720p refer to the resolution seen on HDTV screen. The number before the “p” (progressive) or “i” (interlaced) symbol represents the number of vertical lines in the broadcast. An interlaced signal alternates the odd lines and even lines on the display in a very fast manner which is quicker than the human eye can see.
A progressive scan image fills the entire display gradually with every frame. Better resolution in HD is 1080p, which offers full 1,920 x 1,080 resolution with progressive scanning. These rates translate into a frame rate of up to 60 frames per second, twice that of conventional television thus making the display very smooth and clearer then the regular television sets.
Another advantage of HDTV sets is that they separate the video signal into red, green and blue (component) instead of just one video connection (composite) as in convential television sets. This creates more vivid color and a wider range of hues for a better quality image.
HDTV is the biggest breakthrough in broadcasting since color television sets have been into existence. It offers wider pictures with greater detail and the clarity of motion pictures. Compared to standard television (NTSC), the true HDTV image has twice the luminance component both vertically and horizontally.
HDTV sets can run basically in three resolutions viz 480, 720 and 1080 lines. It’s a step change in television technology which provides far clearer and more detailed pictures than normal “standard definition” TV.
In order to show images from a resolution different from its native resolution, the HDTV set has to convert the image depending on the type of HDTV set.
Most HDTV formats are generally referred to by the number of vertical lines and whether those lines are interlaced or progressively scanned.
Advantages of HDTV
1. The colors of the image on the display generally look more realistic due to the quality of the signal required to process HD video.
2. The visual information is about 2-5 times more detailed overall. The gaps between scanning lines which makes a complete image are smaller thus making the image clearer and smoother in visibility.
3. The increased clarity and detail make larger screen sizes more comfortable and pleasing to watch.
