Interpolation and static images

[cerbul]

I had a chance lately to test a samsung tv with auto motion in 100 hz.
I tested all settings possible from off to maximum.
What I did notice is that the soap opera effect is there, and is especially visible in movies.
Waht I do not understand and I find it extremely annoying is the fact that no matter how static an image was it was obvious which one was with and which without interpolation. As I know interpolation only replaces some frames that are displayed more then 1 time, to make it look more fluid.
But the question is, why on earth do ALL frames get modified? Really, I can't understand why this happens.

One other question would be, are there examples of very bad looking interpolation image?

 

[CrabJuice]

Because 100hz isnt an exact multiple of 23.976 fps?

 

[cerbul]

When I turn off interpolation, is still 100 hz. The only difference "should" be that it repeats the same frame over and over again, until the next frame needs to be displayed. However, it seems that things get modified with static images, where shouldn't exist anything to interpolate. Any idea on that?

 

[CrabJuice]

When I turn off interpolation, is still 100 hz. The only difference "should" be that it repeats the same frame over and over again, until the next frame needs to be displayed. However, it seems that things get modified with static images, where shouldn't exist anything to interpolate. Any idea on that?

The TV need use interpolated frames anyway to avoid stutter, I'm guessing. To 25hz possibly. Did you try to connect a computer to it? Then it will run 60hz also interpolated?

 

[cerbul]

Here is the visual difference between 100hz interpolated at maximum interpolation setting and 100hz with absolutely no interpolation:
- first I don't even want to mention the difference between moving objects, as it is too obvious. However, I can do notice that something about fast moving objects is just not really right. It almost seems like moving objects have extremely variable speeds.
- it almost seems like you compare a full hd to a normal movie, the full hd being the interpolated one.
- even if the image is totally static, you can notice that on objects like curtains, tshirts, pullovers, or anything that is static at some point (when 2 ppl speak), the gradient of the interpolated movie is smoother, making it look more "full hd" then the non interpolated side.
- when you got someone in camera focus, and behind there is a blurred background, which can be very static at some point, you can notice how much more sparkling clean the interpolated side is compared to the other one.

I am very well aware that this effect is called "soap opera effect" and this full hd like thing is what affects the feeling especially in movies, but I really don't understand why there is a difference between static objects. What I do understand from here is that they affect also the frames received, to make the interpolation easier or something. If they would do only the "interpolation" as they claim, then it would not affect the received frames at all, except the frames inbetween.

I didn't think about connecting a computer, but from what I can tell they might use only interpolated images to make the transformation to fit evenly the fps they receive into 100 hz. But even so, I still don't understand why they don't keep clean frames as received, while adding interpolated frames at will. Unless the difference between interpolated frames and original is too big, and they chosen to only use interpolated images instead of the received ones.

 

[CrabJuice]

Sorry. Missed answering to this. Although I dont have many ideas here. No offence, but you might not be technical to describe the problem in a technical enough way for me to understand what you mean. What you're describing could be anything from various filters to some deinterlace stuff or even properties of the panel substrate itself. Someone on AVSforum might be able to understand your problem and give better advice. But even then you need to give more info. Like what type of TV, source-material what settings there are etc.

 

[John721]

I had a chance lately to test a samsung tv with auto motion in 100 hz....
Waht I do not understand and I find it extremely annoying is the fact that no matter how static an image was it was obvious which one was with and which without interpolation...
But the question is, why on earth do ALL frames get modified? Really, I can't understand why this happens...

...- even if the image is totally static, you can notice that on objects like curtains, tshirts, pullovers, or anything that is static at some point (when 2 ppl speak), the gradient of the interpolated movie is smoother, making it look more "full hd" then the non interpolated side.
- when you got someone in camera focus, and behind there is a blurred background, which can be very static at some point, you can notice how much more sparkling clean the interpolated side is compared to the other one...

It's a good question. In the end, I have a feeling that only Samsung's engineers would have the answer. Given that Auto Motion Plus (AMP) is a proprietary technology, regardless of how many competing brands have similar technologies, I think their lips are pretty much sealed. I haven't used an AMP capable TV myself, would you say the static images look subjectively bad with AMP features enabled? I recognize that, based on your descriptions, they've been altered to look different than their original source.

 

[cerbul]

I don't really want to put myself in the boat of hating HD like content. I actually love the clarity of the pictures. However, there is something else, which unfortunately is too subjective to express here, but I will try to anyway.

When I do watch content that is auto motion enabled, I have the feeling that the proportions of moving objects in space is not stable, and every time someone is moving in a movie or show, it feels like is coming closer or goes more far then it normally should. I am almost certain that is a side effect of the applying this technology.

I am also aware that I am making the assumption that their technology being described to add interpolation frames will only do this, adding frames, but instead they are displaying only modified frames. The problem is that the difference between the received frame and the interpolation one is pretty big, and is obvious on static images as well.

I might go a bit more far into the paranoia boat, that this is a mutually agreed practice, to have big quality interpolation detail, so that we move away from lower quality movies. However, the HD like content is not really the one bothering people around the globe, is the artifacts that are visible when heavy movement is made, or when something is moving relative to the camera, the inconsistencies becoming pretty obvious.

CrabJuice: I understand what you are saying, however I am trying to be more specific about it. This has nothing to do with anything that is build in, instead is strictly linked to toggling on/off the interpolation. So the big question remains:
"Why interpolation is not only interpolation, and instead is changing all frames completely."

 

[Nenu]

Sounds like a poor interpolation implementation
If you want to see a good implementation try Smooth Video Project on PC.
If you still dont like it, best not use it.

 

[Mark Rejhon]

"Why interpolation is not only interpolation, and instead is changing all frames completely."

To make it more seamless between the interpolated frames and non-interpolated frames.
And it's because the image is already converted to motion vectors and then back again. You get rounding errors even with a static image.
Also interpolation can jitter (variable motion speeds) quite a bit when interpolation algorithms can't do very fine sub-pixel movements.
(Not all interpolation algorithms seems to do this, however.)

Smooth Video Project on PC.

This is also good for 120Hz computer monitors and televisions capable of 120Hz external signal input -- to interpolate 60fps video material to 120fps. Smooth Video tends to do a better job at interpolation than many of the interpolators built into TV's.


Typically, far better interpolators are found in "960" TV's (e.g. Sony Motionflow XR 960, Samsung Clear Motion Ratio 960, etc), and various newer 2013 model high-end LCD(LED) HDTV's. They do far more processing than the "120" TV's. They actually look fairly good for sports material such as sports scenery pans, but I don't otherwise like interpolators for most other material (e.g. I prefer my movies naturally 24fps).

 

[CrabJuice]

CrabJuice: I understand what you are saying, however I am trying to be more specific about it. This has nothing to do with anything that is build in, instead is strictly linked to toggling on/off the interpolation. So the big question remains:
"Why interpolation is not only interpolation, and instead is changing all frames completely."

What Mark wrote.

 

[cerbul]

Also interpolation can jitter (variable motion speeds) quite a bit when interpolation algorithms can't do very fine sub-pixel movements.

Maybe I understand it wrong. However, I want to make sure before I make further judgement. Does this means that the time needed to create an interpolated frame some times is much bigger then the time between frames, and the end result is that we have a bit of a small break, with fast movement afterwards to catch up time wise, or does that mean that when there is too much work to do to calculate an interpolated frame it will leave the frame as it is, displaying it in the state that is caught when the image needs to be displayed.

Honestly, is not the fact that they chose to make interpolation to the native panel resolution that bothers me, instead there are 2 other things that I notice that happen with interpolation.

1. Sometimes when there is a lot of movement I experience some sort of stop and go performance, just like you would experience packet loss in an internet game, and after a small pause, you get increased running speed to compensate.

2. The fact that when there is minimal movement in a video, the overall shape of the moving objects/people, is not very consistent over time, and is creating an effect of moving in depth towards and away from the viewer of the movie. This might be less obvious the better the resolution of the interpolated content is before any processing.

So what do you say? Can you confirm any of those?