How to experience "motion smoothing" without a high-def TV

June 19, 2023 4:00 PM

The recent post in the blue on Aspect Ratios mentions Motion Smoothing aka "Soap Opera Effect." How can I see what Tom Cruise is talking about without a TV?

I do all my video watching on monitors connected to a laptop, no TV in the house, big screen or otherwise. This hasn't always been the case; the way I'd characterize Soap Operas is more about things happening much more slowly than 'regular' TV shows. (But since I'm clearly not a regular watcher, I may not be understanding this aspect, either.)

It seems this Motion Smoothing is about interpolation: generating and inserting tweens in order to enable higher frame rates. Seems like this would create a better ('smoother') viewing experience, but clearly not everyone agrees. Is messing with the controls of a TV somewhere public my only recourse to actually see and therefore understand what this controversy is all about?

posted by Rash to Technology (16 answers total)

Note that I also have negligible experience with video games, which are often used as an example of this effect.
posted by Rash at 4:02 PM on June 19, 2023

The SmoothVideo Project has tools for many operating systems and video players to add motion smoothing to your video files.

I don't mind high frame rates at all with video games, but good lord do I think movies look bad with motion smoothing. Imagine you're dancing in a club with the strobes on, and everything and everyone looks amazing, you're having a transcendent experience, and then all of a sudden the house lights and emergency lights come up and everyone looks ridiculous. That's motion smoothing while you're watching movies.
posted by eschatfische at 4:14 PM on June 19, 2023

It’s the look- there is a difference in watching video like a live tv news broadcast vs something filmed on real or digital film.
posted by sandmanwv at 4:19 PM on June 19, 2023

If you go to a store that sells TVs, the floor models probably have this setting already turned on.
posted by steveminutillo at 4:54 PM on June 19, 2023

Yep, a Best Buy or somewhere with a wall of TVs should do it. I’m sure you could ask an associate to demo it as well. In my experience it’s very noticeable when watching sports in an uncanny valley sort of way.
posted by tireme at 4:57 PM on June 19, 2023

Seems like this would create a better ('smoother') viewing experience, but clearly not everyone agrees.

It definitely creates a smoother viewing experience. It is, however, not really "better" (at least not to me). It's hard to explain the difference, and a trip to Best Buy as others suggested would help show it to you, but motion smoothing just looks extremely artificially smooth. It's like the TV is trying to predict the next move of every pixel on the panel, and provide a bridge to each pixel's next state from its current state, and the effect is very disorienting.

It doesn't look natural (or make movement look natural) in any way. But definitely go check it out and see for yourself.
posted by pdb at 7:17 PM on June 19, 2023

The article you linked glosses over some concepts. In the old days, the animator animated the key frames but they had an assistant who did the breakdowns. Breakdowns define what happens between the key poses and contribute actual “story” information to the motion. For instance, if you have a human hand gesture where the hand rotates or opens from a fist, the assistant can draw the breakdowns with a sense of the 3D forms. The inbetweener then does something more like interpolation of the line work provided by the previous artists but there is an expectation that they will put at least some effort into sustaining the volumes and flow in an intelligent way.

TV motion smoothing can’t (currently) sustain volumes in an intelligent way. It just interpolates the shapes around in a flat plane, defining nothing and tearing apart the brain of anyone who is sensitive to visual garbage.
posted by brachiopod at 9:55 PM on June 19, 2023

If you search YouTube for "60 FPS", you'll find some clips from movies where someone has increased the frame rate artificially. This will show you what the effect looks like.

The key thing is that more frames per second doesn't mean a superior or more "cinematic" experience. Certainly, if you're used to 24 FPS signifying "film", seeing something at a higher frame rate just doesn't have the same feel. It looks more like cheaply produced television (which, in the U.S., has always been made at 30 FPS).

I always say that the purpose of filmmaking is not to portray the most "realistic" possible version of the world. It's to use images to evoke emotions and ideas. More images per second doesn't necessarily convey the emotions or ideas more effectively or even more vividly. Sometimes, less can be more.
posted by Artifice_Eternity at 10:46 PM on June 19, 2023

I've played around a bit with ffpmeg's motion interpolation filter in various modes. It's really hard to do frame interpolation in a way that doesn't cause some kind of weird visual artifact.

The most noticeable Soap Opera Effect artifacts come from motion compensating interpolation, which tries to avoid creating blurry frames by building the interpolations using the same kind of block motion compensation processing employed for video compression. This is the kind of interpolation that rate-upscaling TVs usually use.

It works pretty well for scenes that feature mostly solid objects with sharply delineated edges such as actors and their faces, or sports players and balls and cars and whatnot, but any background stuff like blowing semi-transparent curtains or clouds or surf or flowing water whose shape evolves with time rather than moving like discrete objects do just looks horrible. Pieces of scenery end up displaying this weird visual vibration that looks completely unnatural and pulls attention away from the point of the scene.

Interpolating between frames that contain evolving shapes in a non-horrible fashion is best done by frame blending rather than motion compensation, but what that does is make all the clearly delineated shapes in the interpolated frames look weirdly blurry around the edges. And that blurriness flickers at the original frame rate, which at least to my eye usually looks worse than not doing interpolation to begin with.

It seems to me that the human brain's inbuilt visual processor is a lot more competent at rapidly tuning out frame flicker than any of the motion interpolation hardware I've seen to date, and doesn't much appreciate having its elbow joggled by attempts to "help".
posted by flabdablet at 3:47 AM on June 20, 2023

Adding: it especially helps to see this if you do the before/after with a high quality motion picture film, well produced with a big budget. A movie you are familiar with.

It's absolutely terrible.
posted by SoberHighland at 5:48 AM on June 20, 2023

Here’s what I think it feels like and flabdablet’s explanation of what happens to the background elements seems key. Imagine a soap opera set from the 80s or early 90s. It’s on a sound stage. The key here is close-ups. The set is maybe a little too flat and a little too bright. Because it’s all about character and zooming in and seeing the emotion. There’s very little background motion or interest because you are there for the personal drama. Papering that look over a movie just affects the atmosphere of the piece and changes your suspension of disbelief that you are watching a real moment that exists in the world and not just on a set. Things in the background should blur out and fade back. Shadows and darkness should be utilized to keep your focus or heighten your awareness. For a movie to be immersive, you need to stop noticing “the movie” and get swept into the storyline. The soap opera look without the attendant storyline just puts you on alert for a hamfisted, melodramatic zoom in on THE LONG LOST TWIN BROTHER!! 👀
posted by amanda at 6:26 AM on June 20, 2023

My favorite example of this is this Star Trek clip where the original clip has been interpolated to a higher frame rate. It’s unnerving.
posted by Betelgeuse at 6:26 AM on June 20, 2023

A YouTube search for soap opera effect will show you a lot of demo videos. Be sure YouTube is playing back at 60fps (click the gear and check the selected quality has "p60" in it.)

Betelgeuse's example is good because it shows a lot of slow scenes with people walking around, where to me it's most noticeable. The Matrix Dodge This example shows how comically bad an action movie can look interpolated up to 60fps.
posted by Nelson at 6:56 AM on June 20, 2023

It looks more like cheaply produced television (which, in the U.S., has always been made at 30 FPS).

Nit: Stuff being broadcast live and some direct to videotape stuff would (IIRC) usually have been 60 fields per second, with no expectation that any given pair of fields would form a coherent frame. Like, a football game would broadcast the even-numbered lines and then, 1/60th of a second later, broadcast the odd-numbered lines from that instant instead of the ones that went with the last set of even-numbered lines (or the next set).

ISTR this is part (and only part) of why live/direct-to-videotape 480i60 looks different from the 480i60 you get from 3:2 pulldown of 24fps film.
posted by GCU Sweet and Full of Grace at 8:02 AM on June 20, 2023

I think soap opera effect is the wrong name for this. IMO it's "this is clearly a closed set and the stuff is clearly made of plastic", and I don't think that 'motion smoothing' is quite the problem, though it occasionally exacerbates the problem. It's that really ultra-high def makes the fakeness of film really noticeable, and you have to dial the settings down to fix it. I'm sure concerts probably look great no matter what.
posted by The_Vegetables at 8:18 AM on June 20, 2023

I vaguely knew this was a thing, read the original post on the blue but didn't have it brought home to me until this Ask.

Can completely see how this is an awful thing... but at the same time I've just watched the Star Trek clip from Betelgeuse and the Matrix one from Nelson at work with the sound turned off, and I'm shaking with trying to contain the belly laughs at the low budget capital-A Act-or vibe they give off. All it needs is 2000s era Google Translate, run those clips' scripts through a dozen languages back to English and then subtitle them with the result.

Astonishing how much difference it makes.
posted by protorp at 9:19 AM on June 20, 2023