There is much talk these days about the frame rates in the new HDTVs. The frame rate is simply the number of different pictures of a TV screen can display in a second, and is also known as an indicator or set of "Hertz". Hertz is the scientific unit for cycles per second and is abbreviated "Hz". The latest buzzword is "120 Hz", a display of 120 frames per second. This is twice as fast as most of HDTV (60Hz) that are capable of, so it should look beautiful at the moving pictures. But,The human eye can only process should be about 20 to 25 different images per second, which is why it does not matter what the framerate, as long as it is quicker than the eye can see?
The answer comes when you know that is not shot any video with the same speed. Movies are usually filmed at a rate of 24 Hz, which is filmed on television, the most at 30 Hz, and some sporting events are now at 60 Hz filmed.
Some simple math will show the problem, and cover the solution. When a TV screen wants to generate 60Frames per second, and the cable-television companies, he sends 30 frames per second, which is easily met: the TV shows each frame twice in a row, making an image of two consecutive frames. Each image is exactly 1/30th of a second on the screen recently, and things will look completely smooth.
So what happens if your DVD player sends 24 frames per second to the TV, but the TV will still show up to 60 on the screen? This is a little slower than cable TV frame rate, so that when itsimply shows each frame twice, and then waits for the next, there is a gap between black and the movie looks terrible. So the TV has a frame triple, double the next, three times the following, and so on, there is show a total of 60 frames per second. This is known as 3:2 pulldown.
The 3:2 pulldown trick works OK, but it is a problem. A picture takes 20th a second, then take the next 30th book. 20. One second is long enough for most people to say thatit's really a static image, and when the camera pans around in a scene, things will seem to move unevenly. But if your TV is able to display 120 frames per second, it can take the 24 Hz input and simply show each frame 5 times in a row for a total of 1/24 (or 5/120) second per frame, with no variation from frame to frame. And when 30Hz video comes in, it displays each frame 4 times in a row, for a total of 1/30 (or 4/120) second per frame. Problem solved.
Now that frame rates are fast enough to any kind of input display smoothly, HDTVs not only a high resolution in X and Y (height and width) dimensions, but also in the t (time) dimension. As in all types of digital media means a higher resolution, smaller units of data, and that natural reproduction does the reality. The 120 Hz frame rate is not very common, until 2008, but some have already HDTVs, such as the Sony Bravia XBR4 series and the Sharp Aquos 92U-series.
HDTV has certainly) in the fourth dimension (time, but has skipped the third (depth) in the process. Until we begin to see holographic films on DVD, we have to wait for a real four-dimensional TV.
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