What is HDTV ?
More than 50 years ago television started to make its way. In 1969, we were excited to see the landing of the moon in black and white. In 2005 however, watching television is more than just a way to relax or to be informed.
The viewer does not only demands diverse and interesting programming, but also a high quality sound and image. Content and quality cannot be treated separately anymore when one talks about television. It is exactly this trend that leads us straight to the roll-out of High Definition Television (HDTV).
High Definition is a matter of extremely good image and sound quality, but above all, it is a totally new experience.. Watching HDTV is an overall sensation, which makes one wonder if it would be possible if one were able to touch what one is looking at.
Basically, TV resolution refers to how many lines are displayed on your TV screen. A non-HD television image in Europe consists of 625 lines of which only 575 are visible on the screen. This format is known as PAL. Outside Europe the most commonly used format is NTSC with 525 lines. In the case of HDTV the image consists of 1080 horizontal and 1920 vertical lines, which immediately explains why the resolution of HDTV is superior than PAL or NTSC.
There are two methods to display the lines on the screen, i.e. interlaced (i) or progressive (p) scan. With interlaced scan each picture frame is created in two fields (phases) of alternating lines, one field for the odd numbered lines, one field for the even numbered lines. The progressive method creates the picture frame as a single image, scanning all the lines in succession. The scan rate is 50Hz, this means that the fields are refreshed 50 times per second.
Currently, HDTV exists in two formats: 1080-i and 720-p. True High Definition Television may have either 1080 interlaced lines, or 720 progressive-scanned lines.
1080-i displays more lines and thus carries more information. As a result it produces better spatial resolution (sharper pictures) when the image is still or has little motion.
Images viewed on TV screens are made up of small picture elements known as pixels. Each of these pixels is made up of three, closely spaced dots of color: red, blue and green. Combined together on a phosphoric TV screen, and viewed from a distance, the colors are seen as one.
The pixels in HDTV sets are square: they are smaller and spaced closer together. As a result, HDTV can display at least 4 to 5 times more detail than analogue TV.
The aspect ratio refers to the horizontal (width) and vertical (height) measurement of the screen. This ratio is also used in reference to how the picture is transmitted and displayed on the screen. The 4:3 ratio is common for standard television. However, the aspect ratio of HDTV is 16:9, which offers a panoramic effect.
This ratio may not be confused with the screen size, which is the screens diagonal measurement.
Euro1080 transmits in MPEG2 (until at least 1st January, 2008). From June 2005 onwards MPEG4 will be its second transmission standard.
By choosing MPEG4 as a transmission standard, Euro1080 commits itself to a pioneering and even market determining role in the evolution of HDTV throughout Europe. The CA Card, which you need to receive the Euro1080 HDTV signal, is already MPEG4-ready.
MPEG4 is an open standard that can address the opportunities enabled by the digital revolution, i.e. to deploy multimedia content in an easy way for any and all platforms. MPEG4 dramatically improves audio and video compression, requiring less bandwidth, and thus enabling the distribution of content and services from low bandwidths to high-definition quality across broadcast, broadband, wireless and packaged media. It provides a standardised framework for many other forms of media (including text, pictures, animation, 2D and 3D objects), which can be presented in interactive and personalised media experiences.
" Source : "Euro1080" web site "