120hz explained

[stockstar1138]

I already posted this in another thread, i put a lot of work into it and dont want to have it overlooked.

i have been hearing a lot of complaints about the 120hz tvs looking "too smooth" in the past i have complained about it to. i was ignorant to how these 120hz actually worked, below is a description on what is causing the "too smooth" look that people are complaining about and that these tvs do not have this problem if the settings are correctly set.


here is the problem you guys are seeing with the 120hz tvs.

they got these motion enhancer settings on and it tries to interpolate changes in the pictures for all 120 frames per second. in other words if i got 2 frames of a movie and the image of the move in one frame is here:



and the next frame is here

xxxxxxxxx

a tv that is set to display the native 1080p24 signal will do this (this is having motion settings set to low or off)

1st frame repeated 5x (24 x 5 = 120)








notice all similies are on the same spot horizontally on the screen as the same image is simply repeated 5 times in a row.

2nd frame
xxxxxxxxxx
xxxxxxxxxx
xxxxxxxxxx
xxxxxxxxxx
xxxxxxxxxx



the motion looks realitively smooth on the screen as all frames are repeated on screen an equal amount of times and the image is exactly how it is encoded vs. a 60hz tv will do this

1st frame





2nd frame
xxxxxxxxxxx
xxxxxxxxxxx

notice that all frames are not repeated equal amounts which creates uneven judder (note: judder is a natural part of 24p film, uneven judder, caused by a 3:2 pulldown is not). to arrive at this a hdtv does something called a 3:2 pulldown.

a 120hz tv with motion enhancers on is going to take a 1080p24 signal and display each frame 5 times, however instead of just displaying the image as encoded it is going to try to interpolate where the image will be at in between frames and is going to go like this
is

1st frame

xx
xxxx
xxxxxx
xxxxxxxx



2nd frame
xxxxxxxxxxx
xxxxxxxxxxxxx
xxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxx

with a 120hz tv with motion settings on "on" or high" every single frame (for 120 frames) will show a different image, even though the film should only be showing 24 different frames per second (each repeated 5 times) when being displayed at native 1080p24 signal. with motion enhancers on it will not repeat the native 1080p24 signal instead it will try to guess what the 4 frames would look like between what the blu-ray player is telling it to display. this is what gives it the ridiculous smoothness look. i hope this clears things up. nothing beats a native 1080p24 signal which you can get with a 120hz tv, but not a 60hz tv. all 120hz tvs should be able to have these motion enhancers turned off.

all those xxxxs were added as space fillers and mean nothing.

[seto]

Nice work on the guide. This makes things a bit easier to understand.

[york weir]

Are the two threads the same?

[Grif32]

Originally Posted by york weir

Are the two threads the same?

There are 3 now

[stockstar1138]

what the hell is going on. i only posted this once

[york weir]

Originally Posted by stockstar1138

what the hell is going on. i only posted this once

LOL, your finger trembling?

On topic, my brother-in-law bought a Samsung LN-T5271F and hated the 120hz feature and turned it off. Is it really only good for material recorded in 24hz?

[whippersnapper]

Originally Posted by stockstar1138

what the hell is going on. i only posted this once

what the hell is going on.

The forum must be doing thread interpolation.

[jjmartin122]

I just got the Vizio SV470XVT with 120hz Smooth Motion and watching sports is amazing!!! Its better than being in the damn stadium!! There is no way I'm ever going back.

[dereksworl]

Originally Posted by jjmartin122

I just got the Vizio SV470XVT with 120hz Smooth Motion and watching sports is amazing!!! Its better than being in the damn stadium!! There is no way I'm ever going back.

I always been highly skeptical of anything Vizio. how does it compare to Sony's and Samsung's 120Hz Motionflow and Auto Motion Plus?

[Minimejer05]

Everytime I go to best buy I see the Sony Bravia(I think or XBR) with the 120Hz motionflow on... god I just LOOVE how fast and smooth it plays. I honestly cant wait to buy one soon... Now I watched a movie on my friends 65 inch DLP with 120Hz..and it looked like a normal movie.. I didnt notice anything movie "smoother" or "faster" is that because there wasnt a motion flow option? His was a 65 inch 1080p 120Hz Mitsubishi Diamond Class.

[skygreenleopard]

Originally Posted by Minimejer05

Everytime I go to best buy I see the Sony Bravia(I think or XBR) with the 120Hz motionflow on... god I just LOOVE how fast and smooth it plays. I honestly cant wait to buy one soon... Now I watched a movie on my friends 65 inch DLP with 120Hz..and it looked like a normal movie.. I didnt notice anything movie "smoother" or "faster" is that because there wasnt a motion flow option? His was a 65 inch 1080p 120Hz Mitsubishi Diamond Class.

Exactly. 120 Hz and MotionFlow aren't the same thing, but 120hz sets ARE capable of MotionFlow/whatever your brand TV calls it. I prefer 120 hz without it, so 24 fps movies look the way they're supposed to in theaters.

So, your friend's 120hz TV was better than a 60hz TV in that it plays the movie at its true smooth 24fps (what I prefer). If he had a MotionFlow-like feature and were to turn it on, he'd get that ultra-smooth video effect that you like, almost an artificial 120 fps. If he were to downgrade to a 60hz set, the movie would show be around 24fps but it'd be inconsistent, resulting in some judder/skippy frames in certain scenes, like slow panning across a landscape or quick movements.

Hope this helps.

[NuSoardGraphite]

Originally Posted by skygreenleopard

Exactly. 120 Hz and MotionFlow aren't the same thing, but 120hz sets ARE capable of MotionFlow/whatever your brand TV calls it. I prefer 120 hz without it, so 24 fps movies look the way they're supposed to in theaters.

So, your friend's 120hz TV was better than a 60hz TV in that it plays the movie at its true smooth 24fps (what I prefer). If he had a MotionFlow-like feature and were to turn it on, he'd get that ultra-smooth video effect that you like, almost an artificial 120 fps. If he were to downgrade to a 60hz set, the movie would show be around 24fps but it'd be inconsistent, resulting in some judder/skippy frames in certain scenes, like slow panning across a landscape or quick movements.

Hope this helps.

A very odd thing though, I watched a Blu Ray in 1080/24p on my 60hz Samsung (it was Dark Knight) and there was no judder whatsoever. It was silky smooth....or at least as smooth as they normally are. No uneven judder to be had...and there are several sweeping/panning shots in that film that make it easy to notice such judder. My Tv does have a "film mode", so maybe that is an anti-judder setting that smooths the motion slightly.

BTW, that was my first Blu Ray on my TV and HOLY COW was it gorgeous. I bought a cheaper tv (Samsung LN40A530 for less than a grand) because I'm too poor to afford an XBR6 and I was afraid that it wouldn't show Blu Ray material as well as the higher priced TV's. Well, that fear has melted away after watching The Dark Knight on Blu. Total and complete AWSOMENESS.

[ObiTrentKenobi]

Originally Posted by jjmartin122

I just got the Vizio SV470XVT with 120hz Smooth Motion and watching sports is amazing!!! Its better than being in the damn stadium!! There is no way I'm ever going back.

You think your Vizio is better than real life? WHAAAA???!???

Wow, try a Panasonic or Sony with 120 sometime then... you'll think you're flying through outer space!

[Jimbowne]

Originally Posted by stockstar1138

i hope this clears things up. nothing beats a native 1080p24 signal which you can get with a 120hz tv, but not a 60hz tv. all 120hz tvs should be able to have these motion enhancers turned off.

all those xxxxs were added as space fillers and mean nothing.

Can you clarify why a 60hz tv cannot use the native 1080p 24hz signal?? I have a 1080p 42" RCA (60 hz) and one of its settings is the 1080p 24hz, so I assume it can display that or there is some adjustment taking place? Thanks

[rubystone356]

I own a philips 47pfl7403D/f7. it can do the 120 refresh rate. I like the tv very much. I know that some people do not like the image from the 120. it works fine for me. had the tv for over 6 months now.

Jacob

[dereksworl]

Originally Posted by Jimbowne

Can you clarify why a 60hz tv cannot use the native 1080p 24hz signal?? I have a 1080p 42" RCA (60 hz) and one of its settings is the 1080p 24hz, so I assume it can display that or there is some adjustment taking place? Thanks

As far as i know its using 3:2 pulldown or 3:2 reverse pulldown to display it. 3:2 reverse conversion will make it somewhat smoother, however it is still not displaying it properly because it is not 24p compatible. you're more than likely still getting judder......that is if you even notice it though......

[ImStylinOnYaBro]

from what i gather, 120 hz looks "fast forwarded" or more popular "soap opera" because of the auto motion features turned on? I notice a lot that my blu rays are looking fast forwarded cuz the movement is jsut so unbelievably crisp and fluent. by turning this feature off, will it give a look more like what i experience on my other tv i used to have , where nothign looked fast forward or soap opera-ish? really new to this, just got a new tv at my current home.

[dustinbaker007]

Will our eyes over time adjust to not notice the soap opera effect? I have had a Sanyo model 47460 for almost 3 years now and when we first bought it It was extremly noticeable. I am just curious on this matter, Thanks, did not know where else to post.