Originally Posted by DanielPlainv1ew
I don't want 120hz if the content is 24 native. That's my question - can't the TV just match the content automatically?
I didn't see an easy to understand answer below, so, an explainer:
Frame rate and Refresh rate are separate. I understand your worry that the TV will modify the original content but rest assured, with motion processing disabled, how it works is as follows:
- The refresh rate is the frequency at which the panel can change the image, measured in times per second(HZ for hertz)
- Frame rate is the number of frames that constitute a second of a given input, measured in frames per second(fps)
- Third confusing factor that some people threw in above is the backlight dimming frequency, also measured in HZ, and this is the rate at which the backlight of the TV flickers. Usually somewhere between 120hz and 960hz. Let's put this aside for now.
Even if you show a static photograph on the TV, there is a refresh cycle at 60/120hz, just without any changes. Imagine it as 60 or 120 copies of the same image per second but without any flicker or gap in between them. It doesn't matter what refresh rate you have, there would be no flicker. (This is where some people conflated the backlight dimming frequency in saying there would be flicker at 24hz)
Onto moving images, let's take a 30fps(Frame Rate) example. On a 60hz display, the display would show each frame for 2(60/30=2) refresh cycles, and on a 120hz display, each frame would stay on the screen for 4(120/30=4) refresh cycles. As you can see, it all fits neatly, and there is no need to modify the original content to fit the panel refresh rate, and you can enjoy your TV show at the original frame rate it was created.
It gets a bit tricky with 24fps. On a 120hz display, all is dandy, 120/24=5, so similar to above, we just keep image on display for 5 cycles and watch the movie as it was made, bob's your uncle. You are watching your content as-is. On a 60hz display however, There are only 60 slots in a second, 60/24=2.5. If we put each frame in 2 cycles like above, we have 48 and that leaves 12 empty slots, and if we put each frame into three cycles, that would make 72, not quite fitting in the slots we have. This is where Telecine/pulldown comes in, explained below.
On your question about changing settings, you don't have to change settings, your TV will figure it out. Your TV will do some magic when there is 24fps content delivered with 60p metadata (Netflix on most devices) as well, not all TVs do this. To remove judder in all sources and leave them in the original form, set Auto Motion Plus to 'Custom,' and Blur Reduction and Judder Reduction to '0'
Telecine/pulldown is nothing new, it has been around since we have been squeezing movies onto the TV format. It is an umbrella term for creative solutions of fitting 24 frames into containers that it doesn't evenly fit in. I will cover the easiest to understand version. Instead of fitting each frame into two refresh cycles, you alternate and put one frame into two, and one frame into three refresh cycles. If we take frame 1,2,3,4 for example, in 120hz it would be 1-1-1-1-1-2-2-2-2-2-3-3-3-3-3-4-4-4-4-4, in 60fps with telecine it is 1-1-1-2-2-3-3-3-4-4. Our brains adapt and mush together the minute difference better than it does judder.
You can look into it more here and learn about what happens when it doesn't fit. https://www.rtings.com/tv/tests/motion/24p