School me on 60 / 120 hz

Without getting too technical, the images we see on a TV are actually a series of flashing images with black frames in between. A 60hz tv will flash 60 images a second.

So what you see as a continual image is actually:

1st frame - black frame - 2nd frame - black frame - 3rd frame

There are no real 120hz input signals outside of PC's...Most US video is 60hz. A screen with a 120hz refresh rate will display 60hz content by repeating frames (60 frames x 2 = 120)

Given that most US video is 60hz/60fps, a 120hz doesn't do much for most material...but it goes a long way with film/movies. Film/movies are shot at 24fps...the juddering that we have grown accustomed to with film is caused by an un-even distribution of frames when displayed at 60fps, on a 60hz display (24 doesn't evenly divide into 60). With Blu-ray we're seeing film being brought over at 24fps....this is where a 120hz display really benefits. 76hz, 120hz, and 240hz displays are able to rectify juddering by evenly displaying frames, as 24 will divide evenly into 76, 120, and 240. A 120hz display will flash each frame 5 times per second (120 / 24 = 5). For a lot of people, movies look odd on 120hz displays because they have grown accustomed to the juddering that makes film look like film.

I think what most people attribute to the PQ of a 120hz screen, however, has less to do with the refresh rate, and more to do with the frame interpolation image processing (auto-motion plus, motion flow, etc etc)

LCD's suffer from motion blur because the pixels in the LCD panel don't move quickly enough to produce the black frames as they should. It takes too much time for the pixels to move back and forth from a frame to a black frame. To rectify this, TV manufacturers intoduced frame interpolating technology, which will predict what a hypothetical frame between two frames would look like. To smooth out the picture, the interpolated frames are displayed instead of the black frames..so it would look a little more like:

1st frame - interpolated 1.5 frame - 2nd frame - interpolated 2.5 frame - 3rd frame.

Some people like how this looks...to others it looks very artificial and computer generated...beacause the image is being processed, and is literally artificialy and computer generated.

It should be noted, that a 120hz display will still refresh at 120hz even if the frame interpolation modes (ie auto-motion plus) are turned off.

Don't know if this will help or not but take it or leave it as you wish.

A camera rolls at 24FPS and a flat panel will display at 8 Mil second response that will give you 60HZ. Some flat panel TVs have a processor to speed up the response time to 120hz/ 4 Mil second RPT for action and fast moving replay scenes. The faster response time will smooth out the " motion blur". Some LCD flat panels have a 240 Hz/ 2 Mil second RPT processor that enhance futher the moition blur.

Most Tvs will give you the option to turn on or turn off the " Motion flow" feature. The "motion flow" processor designs for fast motion playback such as sports, racing cars, football games....other than that in a normal movies, it ain't enhance nothing.

DaveHCYJ wrote: »

You should also note that all this 60 vs 120 vs 240 display rate stuff only applies to LCD type flat panels. Plasma flat panels are effectively immune to this problem (they have their own different types of problems).

Also, the 60Hz your TV displayed may have just been the input signal, rather than your TV's refresh rate. Most input signals today are either 24 or 60 Hz, my TV and receiver will show this "input statistic" information.

Plasmas don't suffer from motion blur, but a 60hz plasma will still judder when playing 24p material. This is why you see 76hz 480hz 600hz sub-field drive plasmas.

Analog Kid wrote: »

My Panny plasma offers a setting for 24p material that allows me to view at 48Hz. The other setting will change the 24p signal back to 60Hz. Are there any advantages to using the 48Hz setting as long as the Blu-Ray player is set to output the 24p signal?

You're going to want to use the 48hz setting anytime you're viewing 24p material...this will eliminate juddering and smooth out the image.

In a movie theater, what do we see? Just curious.

Conradicles wrote: »

In a movie theater, what do we see? Just curious.

24 frames per second