Survey: 60Hz TVs running at 24Hz

[markfilipak]

@FranceBB,

PS: If you're only processing 29.9fps[59.9sps] -- "sps" = "scans per second" -- then there's no reason for going to 119.8fps[119.8pps] (i.e. 4x mv interpolation); interpolating to 59.9fps[59.9pps] (i.e. 2x mv interpolation) will do. If so, then delay the 2nd field stream by only 1 frame (instead of 2) and bob the 1st field for only 1 frame (instead of 2) and then weave.

I suggested 119.8fps because I take everything to 119.8fps (well, 120fps, actually). I do that because most of what I process are 23.9fps[24pps] and mixed 29.9fps[59.9sps]+29.9fps[2-3[24pps]], i.e. "Making Of" documentaries.

[huhn]

he said 2009 and only named one brand. this does not apply today pretty much all display these days are native 120 with 100 mode in Europe too they also usually support 120 HZ input at 1080p or better.

panasonic still does 6:4(3:2 in frames) at 120 HZ with a 24 source when pure direct is used.

2018 was just a bad year to buy a TV with proper 24 HZ support thanks to the 60 HZ limited panels back then.

deint to 120 HZ to properly display 60 HZ source with film or mixed content is a basic feature of sony panels with 120 HZ for like 8 years now.

[FranceBB]

FranceBB can't mean motion vector interpolation because, if the TV is doing the decoding -- doubtful but possible -- then inside the TV at that point there's raw frames.

TVs nowadays are like computers, they can decode and apply all kind of post-processing with a tiny delay. Particularly Samsung is known to apply all kind of processing to the image.


how do you know that's what the TV does? Does it tell you?

It doesn't tell me anything, but what I see is what I also saw in the studio. For instance, if I'm watching Sky Cinema and I'm watching a movie, I know for a fact that we received it at 23.976fps and that it has been speeded up + pitch adjusted by 4% to get to 25fps and then it has been flagged as interlaced, therefore it's progressive flagged as interlaced. When I see it in a broadcast reference monitor from Sony, it clearly stutters 'cause the broadcast monitor receiving the playback from Omneon through SDI just detects the properties and bobs it to 50p ('cause all displays are progressive), however, since it's actually 25p flagged as 25i, both fields are exactly the same, therefore you end up seeing duplicated frames all over the place, hence it stutters (although that's the way it's supposed to be seen by the viewers). What happens then is that if I see that very same content after it has been aired and I receive it with my Sky Q box plugged via HDMI to the Samsung TV, such a TV will see the frame properties (i.e 25i), it will detect internally that it's actually 25p flagged as 25i and it will perform motion vector calculations to bring it to 50p.


Can you describe the artifacts? Are they background "drag" along the boundary of motion objects in panning shots? -- looks like the bow wave and wake of a boat viewed from overhead. That's what I sometimes get with real-time motion interpolation when the interpolator doesn't have enough time. Or by "artifacts" do you mean aliasing? Or maybe pixel twitter -- like sparkling?

Sure. So, whenever you have a pan like a landscape etc, the interpolation is perfect 'cause motion vectors match perfectly and the newly created ones (the artificial ones from the optical flow) are indistinguishable from the real ones, so everything checks out. The problem is when there are fast changing scenes, especially with noise or dynamic grain. In that case, sometimes, you see a frame which has artifacts in some 16x16 blocks like if there are two people fighting there might be a spark in the blocks of the immediately subsequent frames even if it's not supposed to be there. Sometimes you can see things like some "dirt" on clothes like things that are not supposed to be there but that they are due to poor prediction, but you never find things as noticeable as people with 6 fingers or 3 legs etc. I mean, with time this kind of calculation has become better and better and I feel like it will only get better. On the other hand, this is pissing some content creators off a bit 'cause sometimes the choice of shooting to 25p rather than 50p (and divide in fields to get 25i) is something that the author wants and having TVs just doing what the heck they want isn't what they want.


Well, 28fps that actually displays at 28fps will not stutter, so your TV must be doing some sort of telecine.

Well no, I meant that if you send a 28p signal it will not be recognized and the TV will just duplicate it to 60p, hence stuttering. By saying "displaying it as it is" I meant that it doesn't interpolate or blends and just duplicates ehehhehe

You're a pro!

lol, well, I do work for Sky, yeah, but I'm not really interested in buying a new consumer TV right now as I think I'm gonna wait a bit more for when 8K is gonna be supported. Some friends of mine got "punished" for being over enthusiastic about new technologies and buying a 4K TV early on in 2013, 'cause they ended up having TVs which were able to understand BT2020 but no color curve whatsoever, hence being forced to see everything at 100 nits. Luckily I wasn't one of them, but I feel like I'm gonna wait a bit more for 8K and H.266 VVC compatibility.

[markfilipak]

he said 2009 and only named one brand. this does not apply today pretty much all display these days are native 120 with 100 mode in Europe too they also usually support 120 HZ input at 1080p or better.
Thanks, that's good to know -- I don't live in Europe.
panasonic still does 6:4(3:2 in frames) at 120 HZ with a 24 source when pure direct is used.
If Panasonic does pull-down, then how can you say it's pure direct?
2018 was just a bad year to buy a TV with proper 24 HZ support thanks to the 60 HZ limited panels back then.
Well, I guess that's true if the TV manufacturer is stupid or lazy, eh? That's why this is topic interests me so much.
deint to 120 HZ to properly display 60 HZ source with film or mixed content is a basic feature of sony panels with 120 HZ for like 8 years now.
"deint to 120 HZ"? Do you mean bob? And I thought we were discussing 24fps sources, not 60fps (or is it 59.9sps you refer to?). I'm confused.

[markfilipak]

... Can you describe the artifacts? Are they background "drag" along the boundary of motion objects in panning shots? -- looks like the bow wave and wake of a boat viewed from overhead. That's what I sometimes get with real-time motion interpolation when the interpolator doesn't have enough time. Or by "artifacts" do you mean aliasing? Or maybe pixel twitter -- like sparkling?
Sure. So, whenever you have a pan like a landscape etc, the interpolation is perfect 'cause motion vectors match perfectly and the newly created ones (the artificial ones from the optical flow) are indistinguishable from the real ones, so everything checks out.
I'm sorry, I guess I didn't fully explain "background 'drag' along the boundary of motion objects in panning shots". Suppose a camera tracks a car along a highway (or a person crossing a room). That's a motion object in a panning shot. Perhaps I should have said "tracking shot", eh? The car (or person) appears to stand still while the background pans. That's when I see 'artifacts', meaning: image distortion along the boundary of the car (or person) between the car (or person) and the panning background. I likened it to looking down from above at a boat -- the boat's bow wave and wake 'distort' the water and looks like the effect I'm talking about. Does that make it clearer and is that the kind of 'artifacting' you are talking about?

PS: Some people call that "background drag", "ghosting".

[huhn]

If Panasonic does pull-down, then how can you say it's pure direct?
tell that panasonic not me.

"deint to 120 HZ"? Do you mean bob? And I thought we were discussing 24fps sources, not 60fps (or is it 59.9sps you refer to?). I'm confused.
this is field matching and mostly likely frame adaptive deint but not sure how the deint type matter if this is just about how a 24 FPS signal in 60i or 60p is treated.

[markfilipak]

"deint to 120 HZ"? Do you mean bob? And I thought we were discussing 24fps sources, not 60fps (or is it 59.9sps you refer to?). I'm confused.
this is field matching and mostly likely frame adaptive deint but not sure how the deint type matter if this is just about how a 24 FPS signal in 60i or 60p is treated.
Well, I'm still confused and frustrated trying to figure out what you mean. You know that people toss around the word "deinterlace" when they refer to any process that involves deinterlacing, even when it's undone at the end of the filtering, even with progressive frames, eh? Do you mean real deinterlacing of scan fields? I think you do. But what has that to do with 24 or 23.9fps? What are you getting at and what does it have to do with TVs? TVs don't deinterlace interlaced scan fields, do they?

What the heck does 'field matching' mean to you? What does 'adaptive deint' mean to you? This is all too abstract, using 'terms' that only have meaning for you, in your head.

PS: I'm sorry for showing my frustration. Can we stick to the types of videos found on DVDs and BDs, please? Otherwise, there's no end to discussion of all the possible video formats.

[markfilipak]

@huhn,

Would you mind terribly if I petitioned to remove your posts and my replies to them? They really are off topic. Please say it's okay.

[huhn]

no...

frist result for adaptive deint: https://link.springer.com/chapter/10.1007/11582267_48
TV use this for a long time and intel, nvidia and AMD (not dual rate) have them also known as motion *compensating or frame adaptive deint.


field matching:
http://underpop.online.fr/f/ffmpeg/help/fieldmatch.htm.gz

and yes TVs do that. and is important to understand why some TVs can't like those with 60 HZ panels and other can with 120 HZ while they maybe even be able to display a 24 HZ signal correctly (sony only) but this feature is missing.

it would be nice if very easy to google terms are not suppossed to be in my "head" i don't like been insulted thank you. and yes these are obviously applied to DVD, BD and alike or simple broadcast signals.

[ognirats]

Smooth motion setting sucks. My Sony had it enabled on one app without an easy way to disable it. I eventually managed to turn it off. It was a hell

[ognirats]

no sony found a way to display 24p correctly on 60HZ panels the majority can't

Is there any more info on it?

[huhn]

these TVs can't frame interpolated with a 60 HZ signal. they can't judder free display 24p using the build in app (runs at 60 instead of 120).

beware recovering 24p from a 60 HZ source is part of the "smoothing" settings but it needs to be setup correctly so it just creates the orginal frames without frame interpolation.

x800H is currently one of these
https://www.rtings.com/tv/reviews/sony/x800h

[ognirats]

"Can't frame Interpolated"?


Can you please explain what are you talking about

[markfilipak]

"Can't frame Interpolated"?


Can you please explain what are you talking about
I think that huhn means: The Sony TV that was reviewed doesn't frame interpolate a 24fps video (movie, cinema camera) well because it has a 60Hz panel, not a 120Hz panel.

Any TV with a native 120Hz panel (or a true variable refresh rate panel) can display 24fps perfectly via simple 1-to-5 frame repeat (i.e. 5x frame rate boost) whereas a native 60Hz panel requires 4-to-10 field repeat (i.e. 2.5x frame rate boost) via either telecine (which either judders or is so smoothed out that faces look like plastic) or interpolation (via either pixel interpolation or motion vector interpolation).

Pixel interpolation is fast but it results in fuzzy pictures that, for fast motion is relatively unnoticable, but for smooth motion is noticable.

Motion vector interpolation is better at retaining sharpness but MV block size -- the motion vectors are per-block, not per-pixel -- becomes an issue. Large MV blocks are more apt to produce motion vector block artifacts that are similar to macroblock blocking (e.g. the blocks seen in low detail, low contrast areas on non-HDR TVs).

MV artifacts show up mostly in tracking shots: Shots in which an object (a boat or a plane or an actor) 'appears' motionless as the background moves. The artifacts can be avoided by adaptive analysis of the picture content and/or by using smaller motion vector block sizes. But perfoming MV interpolation in the TV is a real-time situation because the TV has to produce a new picture every 1/60 second. Really good adaptive analysis and smaller MV blocks simply take more time -- too much time -- than most TV's can afford.

When I started this thread I hoped to avoid these kind of detail discussions and simply compile a list of TVs that display 24fps content well.

I've concluded that, in order to process 24fps video with sufficiently small MV blocks and sufficient adaptive analysis, I have to transcode them (decode - interpolate to 120fps - encode) before sending them to the TV. That requires a chain of 3 functions that are available to VapourSynth: Super() followed by Analyse() followed by SmoothFps(). The plugin DLLs that accomplish that were developed by the Smooth Video Project (SVP) but it's objective was to accomplish the 120fps conversion in real time (for use inside TVs), not as part of transcoding. As part of transcoding, the process could take whatever time it requires but SVP is not set up to take 'whatever time it requires'.

If you bring up my thread history in the VapourSynth sub-forum and look at what I've been posting you'll see the direction I'm taking. But understanding Super() and Analyse() and SmoothFps() is not easy, and understanding how to adapt Super() and Analyse() and SmoothFps() to (non-real-time) transcoding is difficult due to lack of detailed documentation.

I could use some help and some support in the VapourSynth sub-forum.

PS: The required transcoding could be done via ffmpeg but for 2 problems: 1, the ffmpeg MV interpolation routines are poor, and 2, the ffmpeg developers are busy supporting streaming and are not interested in non-real-time issues.

[ognirats]

oh, he meant "Those TVs cant interpolate 60hz video"...

[ognirats]

Any TV with a native 120Hz panel (or a true variable refresh rate panel) can display 24fps perfectly via simple 1-to-5 frame repeat (i.e. 5x frame rate boost) whereas a native 60Hz panel requires 4-to-10 field repeat (i.e. 2.5x frame rate boost) via either telecine (which either judders or is so smoothed out that faces look like plastic) or interpolation (via either pixel interpolation or motion vector interpolation).


I am pretty sure my BRAVIA doesn't interpolate/3:2 pulldown 24hz sources. How does it do it then?

[wonkey_monkey]

Is this why so many American TVs can't display 50fps? Because they use fixed 60Hz or 120Hz panels, whereas in PAL land they more or less have to use variable rate panels?

[markfilipak]

oh, he meant "Those TVs cant interpolate 60hz video"...
huhn wrote: "these TVs can't frame interpolated with a 60 HZ signal. they can't judder free display 24p using the build in app (runs at 60 instead of 120)."

I guess the interpretation is up to the reader, eh? And how do you know what he meant? For that matter, how do you know that huhn is a 'he'?

PS: That brings to mind the cartoon: "On the Internet, no one knows you're a dog." -- a dog holding a cell phone, to another dog.

[markfilipak]

I am pretty sure my BRAVIA doesn't interpolate/3:2 pulldown 24hz sources.
Of course not.
How does it do it then?
It doesn't.

A 24fps source with 3-2 pull-down (or 2-3 pull-down, which is much more common) is called "hard telecine". Why/how would a TV interpolate a hard telecined stream?

[markfilipak]

Is this why so many American TVs can't display 50fps? Because they use fixed 60Hz or 120Hz panels ...
That's the rumor/rumour. The real reason, I think, is that the U.S. government lets companies get away with non-competitive bullsh*t -- the U.S. government has been bought.

PS: That reminds me of the old joke: The United States has the best politicians that money can buy.
... whereas in PAL land they more or less have to use variable rate panels?
I doubt that. Variable rate panels haven't been around that long.

Your TVs run 24fps cinema at 25fps (4% speedup) unless the frames been treated to Euro pull-down. And I'll bet there's a Euro telecine that adapts 29.970fps to 25fps. ...Or are you saying that you can take a Region 1 DVD that's hard telecined to 30000/1001fps and play it on a d-PAL TV and people don't sound like they're falling asleep or on tranquilizers?

[ognirats]

https://imgur.com/a/FXevmEn

https://imgur.com/a/M0UH3rW

[markfilipak]

https://imgur.com/a/FXevmEn

https://imgur.com/a/M0UH3rW

Do you want to make a point? What is it? You have my full attention. :)

[wonkey_monkey]

Your TVs run 24fps cinema at 25fps (4% speedup) unless the frames been treated to Euro pull-down.

Not when I play a blu-ray out to it, it doesn't. The screen blanks and then pops up an info box saying "24Hz", just as does when switching between TV (50Hz) and console (60Hz).

All appear to be the correct framerate without interpolation.

[huhn]

Is this why so many American TVs can't display 50fps? Because they use fixed 60Hz or 120Hz panels, whereas in PAL land they more or less have to use variable rate panels?

they most likely simply don't bother adding it. they are clearly don't produce worse panels for the US instead of the same panel for every country.

I doubt that. Variable rate panels haven't been around that long.

Your TVs run 24fps cinema at 25fps (4% speedup) unless the frames been treated to Euro pull-down. And I'll bet there's a Euro telecine that adapts 29.970fps to 25fps. ...Or are you saying that you can take a Region 1 DVD that's hard telecined to 30000/1001fps and play it on a d-PAL TV and people don't sound like they're falling asleep or on tranquilizers?

i have not seen a TV or even monitor in germany that can't natively do 50 HZ and 60 HZ and i count CRT into this too. of cause we can play all region on our devices why wouldn't we... you just need to rip it, have a player of that region or a region lock free player.

I am pretty sure my BRAVIA doesn't interpolate/3:2 pulldown 24hz sources. How does it do it then?

we can only guess or your device is just a native 120 HZ panel which is very common for sony TVs.
maybe they just do 48 HZ and the rest didn't come up with that simple trick. taking an old TV with 50 and 60 HZ support and giving it a custom refreshrate of 48 HZ is pretty trivial. modern TV don't like custom refreshrate anymore they may work but huge changes are suually rejected on the other hand they are usually 120 HZ anyway.

pulldown is part of interlacing/telecine while i totally undertstand what you mean 3:2 judder should be clear enough and no there is no difference between 3:2 or 2:3 it's just where you start counting.

[ognirats]

we can only guess or your device is just a native 120 HZ panel which is very common for sony TVs.

If that's true than it's kinda stupid of them for not making it an option

[huhn]

not exposing 120 HZ is very common in the past. than it was generally available at 1080p and 1440p on many brands and with HDMI 2.1 2160p120 was now possible too and is pretty common.
you can just look up your model on rtings to fugure it out or just send 60 HZ and destroy your image quality with the frame interpolation "feature" if it is possible to do that it has to be 120 HZ.