Hi all, I went to a friend's house who recently purchased a 40 (or 42) inch LCD HDTV. Samsung brand. It had this enhancement feature called "120Hz motion" or something like that. Anyway, he showed me some hd movie channels and we were watching some drama with Sandra Bullock. The very first thing I noticed was that in scenes were there was faster/fast action such as a person just walking down a hall, the "120Hz" feature changed the action in such a way that it appeared slightly sped up to me. the explanation is that this reduces the motion blur? But the effect is that the movie at times no longer looked like a "movie" or the way I would watch it on a standard tv. And when we popped in a dvd for Batman Begins, things looked even "worse" to me. All the fast action scenes, especially the training scene on the ice, now looked like the film was shot and appeared as if it was a British soap opera or mystery drama. Is this really what HDTV's do to movies? They call it enhancing, but now to my eyes it seems I'm not watching a "movie" at all. Everything appears as if they were using a different camera/lens filter. My friend said "it looks so real now!", but I was surprised to not be impressed. I don't want the movie to look "so real". I want the movie to look like the way I watched in theaters and when I watched in on my standard tv when it still appeared on the screen like a "movie". I thought HDTV simply enhanced/enlarged/the picture quality, and not affected how the images actually "look" on screen. Can someone shed anymore light on this to me? I'm somehow now not in a rush to get an HDTV if everything now appears like they're filmed with a high end HD home video camera, and not a traditional video camera used by the original filmmakers. Someone help! Am I the only one noticing these visual subtleties? *By the way, we even changed the tv settings to disable the "120Hz motion" feature and the tv still exhibited some noticeable (by me) "speeding up"/"smoothing" of the fast motion scenes.
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My 40 inch Samsung LCD HDTV is a year old and it doesn't have this "feature". I have no idea what you are talking about because I've never heard of or seen anything like this. Everything looks great on my TV and I've never seen the effects you are talking about. Maybe it would be good to find the model number and look for reviews on the internet. Maybe this effect is specific to this model.
Do note that with video and audio that a minority of people are unusually sensitive to various encoding artifacts. I remember working with a guy who was just adamant that any MP3 file recorded at less than 224 Kbps was "unlistenable". Most studies have shown 192 Kbps MP3 to be indistinguishable from the original for most people. I have forgotten the name of it, but there's a type of HDTV technology that for about 10% of the population it is completely unwatchable because they react so negatively to the way this technology works. It has something to do with color perception by this type of technology. Perhaps you are unusually sensitive to this weird new technology by Samsung. If so, my advice would be to seek out an HDTV that doesn't use it at all.
Whatever is happening, it seems to me from reading your post that you are perceiving everything as looking as if it was it was shot on video tape rather than film. This would certainly be a glariing way to view anything actually shot on film and I can understand why you would not like this, but again, I've never heard of or seen what you are talking about, so I can't personally comment on it.
Originally Posted by breakchange
I know how 120Hz is supposed to work. What you describe seems different.
First film is shot at 24 fps. When you view a film in the theater, each frame is repeated in the projector gate two (48 fps) or three (72fps) times to reduce flicker but motion is continuous to the eye.
Second normal TV and interlace DVD use a process called "telecine" for film source to repeat fields in a pattern that builds frame rate from 23.976 fps to normal 29.97 fps used for NTSC television.
Details here: http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm
Advanced HDTV sets reverse the "telecine" back to the original 23.976 fps progressive frames and then frame repeat 3 then 2 then 3 and so on to 59.94 fps for display. This has a slight juddered look during motion.
Progressive DVD stores film as frames and uses a similar 3 then 2 frame repeat to the progressive TV for display.
120Hz is an attempt to remove the judder resulting from 3-2-3-2 frame repeats. After reverse telecine to 23.976 fps, frames are repeated five times each to 119.88 fps. This is supposed to reduce flicker and produce smooth motion.
The 120Hz feature is found only in recent advanced HDTV models. Sony has a similar feature for Blu-Ray high definition DVD when paired with a particular Sony HDTV model.
Turns out Samsung has two methods to 120Hz for film source. One is similar to the way I described where each frame is scanned (refreshed) 5 times. They also have "Auto Motion Plus" where intermediate frames are interpolated for 120Hz.
and select this animation.
I need to see this.
Very interesting edDV. Thanks for the links. I stand by my supposition that perhaps the original poster is just simply unusually sensitive to this technology. Either that or it simply doesn't work as well as it is supposed to. Either way, the only "fix" would appear to be to avoid TVs with this feature.
The Samsung models have three levels of operation (low, medium, high) and off.
Using only the 120 Hz option (no interpolation) does indeed eliminate the judder from 3:2 repetition. Of course, you still have the jerkiness from the low film frame rate.
The motion vector interpolation doesn't always work right, just like using AVISynth's MVTools to do the same thing. When it does work motions are very smooth. If you like the jerkiness of film you won't like the feature.
The Samsungs with this feature have a demo mode where you can see the usual usual 3:2 repetition (really 6:4 at 120 Hz) and the smoothed version side by side.
Since here in North America we are so used to judder and motion blurring from watching movies on NTSC TV's for decades, these 120hz sets that eliminate telecine pattern judder by multiplying the film's original 24 fps frame rate by five times produce a weird video-like effect... I think that is what the OP is talking about. Movies wind up looking more like high def video than film.
This is still a very new feature on only a handful of the most recent HDTV's. The vast majority still have judder.
Originally Posted by gshelley61
I do agree that over sharpening a film source looks artificial and distracting.
Originally Posted by gshelley61
Originally Posted by edDV
My initial thought about interpolating new intermediate frames is more artifacts may be introduced by this process with net negative benefit. Motion interpolation accuracy depends on noise and the size of the blocks being analyzed. Also, the source is highly compressed 14-25Mb/s MPeg2 which has already been motion processed vs. the 144Mb/s HDCAM tape being played by HBO et. al. to load the server.
I think the burden of proof is on Samsung that intermediate frame interpolation is a good thing.
PS: Another interesting issue on 120Hz is these sets are using LED backlights vs. traditional CFL (fluorescent)backlight. LED's allow a variety of light modulation and frequency modulation tricks.
One of the biggest draws to 120Hz is to avoid 3:2 pull down which is great for 24p. Film is 24 frames per second. That standard was the approximation of what was defined in the early 20th century by hand crank cameras. And just about every movie disc you can buy is encoded in this format. We're not just talking DVD. We're talking about HD DVD and Blu-ray, too.
The problem is, most TVs run at 30 frames per second. Fitting that 24-frame content onto a 30-frame screen isn't that easy; the math just doesn't compute cleanly. You can't divide 24 by 30 without filling in the gaps with some junk. That junk causes stuttering in the video. This is a jerky-looking phenomenon that's particularly noticeable when the camera pans across a scene. The conversion is better known by film and TV wonks as 2:3 pulldown. It spreads out 24 frames into 30 by placing one frame on the screen three times and the next one after that two times, and repeating this pattern ad infinitum.
How does this relate to an 120Hz HDTV showing frames at 120 frames per second? A bit of simple math tells you that 120 is a multiple of 24, because 24 x 5 = 120. So one of the claims of the purveyors of these sped-up monitors is that they can natively reproduce 24p programming, namely, just about every film has ever been shot.
These new HDTVs avoid this awkward 3:2 pulldown process altogether by changing their frame rate to something that's a multiple of 24 by using either frame doubling or interpolation (also called "tweening"). Then, their playback can be as close to native 24fps playback as you can get. That's why 72Hz (24 x 3 = 72) and 120Hz refresh rates are gaining traction. Native 24p playback: Yeah, sounds good. But how will it be implemented and which manufacturers are involved? And who does it best?http://www.absolutevisionvideo.com
BLUE SKY, BLACK DEATH!!
Originally Posted by Marvingj
Direct 24fps playback will never work without higher refresh due to flicker. That is why film projectors repeat frames 2x or 3x in the gate causing that traditional projector klacky sound.
PS: The PAL world has stuck with 24->25 speedup to match film to broadcast frame rates. Advanced PAL TV sets use a 4x refresh to 100Hz. There isn't a convenient common multiple of 24 and 25.
What's wrong with a tv using a framerate of 24 fps ?
LCD tv doesn't flicker, does it? Or am i mistaken?
I don't understand why the same image should have to be thrown up there 5 times, when the display type is LCD anyway....asdf
LCD tv doesn't flicker, does it?
Originally Posted by manono
It seems more logical to play the movies at 24fps, since thats what they were filmed at, rather than repeating each frame several times.asdf
Originally Posted by iThinkYouBrokeIt
LCD uses a backlight that is always full white*. Color is achieved by RGB filters blocking the light in proportion to the pixel color desired. Black results when RGB filters are all at full block. Any light that leaks through the RGB filters causes poor blacks (often a dark gray or blue).
Backlights are usually CFL fluorescents that can have relatively long persistence (low flicker) since they aren't painting motion. The RGB filters modulate the light at frame rate to create the illusion of motion. The problem is the "color" being formed per frame remains full on until the next frame update. Since the eye has a persistence, it won't detect an instant motion update so tends to perceive a blur as motion is painted across pixels. Also the RGB filters may not fully respond to a white to black transition taking more than one frame to complete a color transition. The result is smeared motion without flicker at traditional 60Hz refresh.
Tricks used to reduce smear rely on speeding or modulating the light filters to pulse pixel color down to near black before the next refresh. Advanced techniques modulate the filters several times between frame updates and/or add interpolated intermediate pixel values.
* Dynamic contrast modulates backlight brightness to "help" dark scenes appear as deeper black.
Sony XBR5 series (with 120Hz MotionFlow) does the same but only when the Motion Enhancer feature is set on. Looks COMPLETELY like videotape when the enhancer is set to HIGH mode. I can;t provide a lot of technical detail as to why or how it works so I'll give my subjective impressions: (some of you guys on this forum are really into the technical reasons for this stuff (my total respect ! - some serious gurus here)
Notice it most with older movies actually - probably because it makes them look so different compared to how one is used to seeing them. In Canada, the Movie Network/MPIX HD has been showing just about all the James Bond flicks. There are new pristine digital transfers that are staggeringly clear and crisp. Turning on the motion enhancer looks like someone shot them with a HD camcorder in an overly-lit room. The effect is bizarre to say the least, but reveals details in skin tone, makeup, and lighting not noticed before. Water scenes reflect sunlight like never before. The motion enhancer also seems to create a 3D like effect. Moving foreground objects appear to pop out compared with softer focus backgrounds.
One thing I find interesting is that it often reveals where the light sources on the set are. As the effect is rather extreme, at high motion or when there is a lot of camera panning in a scene, it generates artefacts - there are ghost images that appear 'behind' moving characters. For this reason, I set the Motion Enhancer to 'Standard'. The effect brightens the image, gives a crisp bright detailed videotape look, but is not too distracting.
It's a matter of preference, but interesting to me that this technology can so 'colour' the end result.
Purists, stay away: you'll find it too distracting. It's fine to have the choice. I don't know how (or if) this is the same implementation on the Samsung sets, but all I know is that if I couldn't turn it off that it would be really annoying. It doesn't always work well: highly source dependentNobody's fault, but my own....
The three Samsung models that have the "setting the auto motion plus 120hz"
Owners manual states: options are off, low, medium, high or demo
There is a firmware update for the problems with this motion plus 120hz that is supposed to correct.fast eddie
I actually can't stand the HDTV or HDDVD's either (thank god they're out of here now, we just have to deal with blu-ray) It's just that the things look so real that they make it look fake. Maybe its too much of a bother right now or we just need to get use to it but yeah. It's not working out for me. I'll stick to the dvds.
Adding frames to the framerate is what make the picture look so real on 100HZ/120Hz. Samsung started this, Sony followed and now Sharp and Philips.
It is a technology created on the MSU laboratories for Samsung.
The noise this technology creates is called "hollow effect". It caused because of the bad morphing between 2 very different frames. Very usual on fast scenes.
Most LCD / Plasma panels don't playback 24fps. The picture staters. Some latest screens supports that framerate natively.La Linea by Osvaldo Cavandoli
I have to agree with your opinion on the soap opera or british show look. I just purchased the samsung 240hrz 150contrast and I Really don't like it at all. Spent $1500 on the tv and am probably going to return it. it makes the movies look cheap like it was filmed with a video camera or maybe a video game intro. This look might appeal to the gaming generation but NOT to me. If this is what High Def doe's than you can keep it cause I don't get it.
Originally Posted by SatStorm
Originally Posted by rockstar1958
At least the frame repeat of 24 fps to 120 fps (5:5) or 240 fps (10:10) gets rid of judder of 3:2 repeat for 60 Hz TVs.
@edDV: 2 years ago, many LCD screens had a stater problem when you feed them 24fps. At the time being, we (reviewers) thought that it was about the bad support of the specific framerate. Time showed that this is not the issue.La Linea by Osvaldo Cavandoli
I have the exact same issue here with my Samsung Full HD LCD TV
When I just bought it my nephew came over and we both saw directly the diffrence with normal TV's, he also said 'it looks real' not that is a good thing.
Now I watch films mostly on a small 4:3 TV or MonitorThe flag once raised will never fall!
120/240Hz=fake look that the manufacturers are pushing on us,I prefer the look of 24p.
Read the reviews from the experts and most say turn it off.