What is the difference between EDTV and HDTV?
Shopping a new television can be a bit complicated today. This article will try to clarify at least part of the image by explanation of the difference between the improved TV (EDTV) and High -resolution TV (HDTV). In this process we also define TV standard definition (SDTV).
A certain amount of technical information is required. The TV shows a moving image by running a set of static images in quick succession to create the illusion of movement. These images still flash at 30 frames per second. However, to display a single frame, the TV must "paint" a screen or image, line by line.
The standard TV screen consists of about 480 scanning lines . Television first receives data for even numbered lines, then it must make the second pass to fill the odd numbered lines to complete each frame. Both passages together take place in the range of 1/30 seconds. Because each pass paints every other line, this type of display is marked as interlaced or 480i. This is also called 525i, because 45 other "blank lines" are built into each frame transmission to display the time to reset. However, the correct designation is 480i or standard definition TV (SDTV) .
This technology was fine for smaller screens, but as the displays have increased, 480 scanning lines were visible, as well as artifacts created by interleaving technology. Objects in the movement that created offset or jagged lines between the first and second passage were visible on large screens, leading to poor image quality. Simply put, TVs with a large screen only increased SDTV shortcomings. Enter progressive scan .
Progressive scanning television paints the entire frame in one sequence passage, which eliminates most of the distortion that creates a two -class interleave. Though TVR still a receivest video frame in two parts combines data before painting using an internal processor called deinterlacer , also known as line doubler . Progressive scanning displays are specified as 480p or 525P, more often called Improved TV (EDTV) definition .
EdTV represents a significant step forward in the display technology and creates a much finer picture than the interlaced TV. Deinterlacer not only assembles the frame, but also cleanses any artifacts in the process. In addition, EDTV can paint a complete frame in 1/60. seconds, allowing him to paint the same frame twice. This creates a cleaner and more stable image. EDTV also has a 16: 9 aspect ratio, which means that the display is rectangular or theater. Finally, EDTV can portray high -resolution or HDTV broadcasting while SDTV cannot.
You may ask, "If EDTV can portray high resolution broadcasts, why get HDTV?" The short answer is that HDTV may bepacking HDbroadcast in better resolution than EDTV. Although the quality of EDTV looks closer to HDTV than standard television, everything else is the same, HDTV overshadows EDTV when it comes to broadcasting with a high -resolution of span that some experts put at about 20 percent. How does HDTV do it? Adding additional scanning lines for finer resolution and greater clarity.
While the EDTV has 480 scanning lines, HDTV supports two high -resolution broadcast formats: 720p and 1080i. 720p is a progressive scan with 720 scanning lines, while 1080i is interleaved by 1080 scanning lines. Generally speaking, the more scanning lines, the better the resolution, especially when considering large screens.
It may sound contrainuitive that HD broadcasting would use the interlaced signal, but with so many scan lines, any artifacts are too small to be evident and higher resolution is breathtaking. Nevertheless, 720p is preferred for rapid movement, as a progressive scanning techniqueAble to redraw the picture faster and improve movement. So football games and other sports are broadcast in 720p, while "normal" HD broadcasting is in 1080i. HDTVs accept either format and do good work in their display of both and many people cannot recognize the difference between them. They are significantly brighter than the 480 EdTV scanning line.
Therefore, although high -resolution broadcasting looks great on EDTV, the signal is converted into 480 lines to display it, and the process is lost part of the extra clarity that HDTV maintains. This is a real reason to buy HDTV - for this "extra 20 % clarity" when watching HDTV programming. Some HDTV (1080p models) UPConvert 1080i transmits by secreting them and displaying them as progressive scanning images.
Not all HDTVs are better than EDTV while watching the 480i standard , VHS tapes or DVD monitoring on non -slogan scanning DVD players. High -quality EDTV with good deinterlacer can these interlaced signalsProcess better than HDTV with a low end equipped with bad deinterlacer. But as soon as he marches, it makes sense to buy HDTV.