LG is taking the Hz game to the next level with its TrueMotion LCD TV. LG will be showing off its overkill 480Hz TV at this years CES. While Sony just got done with an advertisement campaign for its 240 Hz TVs it goes to show that Hz is the new mega-pixel race.
Our technology history has been filled with many size races; always based around the idea that bigger is better. You can look back to the early days of AMD vs Intel where clock speed was the defining factor of a CPU, mega-pixel race for digital cameras and now the Hz race for televisions. As it is now understood for the CPU market clock speed is not an indication of performance, nor is a high mega-pixel camera anything without a decent lens and higher Hz is not any better for televisions.
To fully understand why the higher Hz is not always better (and not worth the extra coin) there are some basics that need to be understood. The benchmark of 120Hz allows for video and film to be played back without the need of extra pull down technologies. Film is shot at 23.94 FPS (frames per second) which is rounded up to 24 FPS but the USA and many other countries adopted the NTSC standard which shoots video at 60 FPS technology.
The problem is that some parts of the world shoot in 24 FPS while others shoot at 60 FPS. The two formats are not directly compatible and need a "pull down" technology to make the transition. For countries that use SECAM standard a 2:2.1 pull down can be used which results to ~5% speedup ( 24 FPS becomes 25 FPS). Because of the slight speedup an audible pitch difference is noticeable but generally an audio filter can be used to disguise the difference.
NTSC with its 60 Hz can't be slowed down to the 20 or 30 Hz needed to reproduce the 24 FPS. For this a 3:2 pull down technology is used to supplement the interlaced nature of broadcast television. It essentially involves repeating or mixing frames that can result in the "judder" which is a result of the speed difference and the mixing of frames. It will be more apparent in slow panning shots where only subtle movement occurs, the faster the movement the harder to see the "judder".
120 Hz television can remove the "judder" by accepting 24 Hz input and using a 5:5 (24 * 5 = 120) pull down which shows each frame 5 times for smoother playback to the viewer. No further technology is needed as the format can be replayed in equal parts with no distortion. The same works for 60FPS as a 2:2 pull down can be used ( 60*2 = 120) resulting in fluid motion and no further technology is needed. This equal distribution results in negligible "ghosting" and is the optimal Hz for the current television standards.
Why is all that background information relevant to the 240Hz TV from Sony and the 480 Hz TV from LG? It goes to show that the Hz race is nothing more than a frivolous attempt at getting more dollars out of your pocket. The difference between the 120,240 and 480Hz has a diminishing return affect as 120Hz is the optimal refresh rate (as per dollar to benefit ratio). Be warned that the TV manufactures are going to attempt to brainwashing the consumer into thinking the higher the Hz the better the TV. Take it all with a giant grain of salt as 3Ghz P4 is not better than a 2Ghz Core 2 Duo.
Special thank to "Random John" for his expertise on the subject.
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