Survey: 60Hz TVs running at 24Hz [Archive]

markfilipak

19th March 2020, 06:44

no sony found a way to display 24p correctly on 60HZ panels the majority can't do that they need 120 HZ display to do that.
As you probably already know, when fed a 24 FPS video (such as Blu-ray), a 120Hz TV simply repeats each frame 4 times (total: 5 frames, i.e., 120Hz/24Hz = 5). The result is perfect 24 FPS. As I know you know, when fed a 24 FPS video, a 60Hz TV coverts each 4 frames to 10 frames,1, to 30 FPS via 2:3 pulldown (i.e., 30Hz/24Hz = 5/4) followed by, 2, repeating each resulting frame 1 time (i.e., 60Hz/30Hz = 2).
if you are using a custom resolution to force 24p you are playing with fire and this has to be an low end TV: https://www.testufo.com/frameskipping
I have a comment and a confession. Comment: I'm not forcing it. According to the MonInfo application, the TV reports 23Hz to 76Hz in its HDMI capabilities. Confession: After I wrote to you last, I finally pulled my head out of my a$$ and realized I already have everything I need to determine whether my Sharp TV can operate in native 24Hz mode. It can't. I now know for sure that it's native 60Hz, and that, when fed 24 FPS, it's doing 2:3 pulldown.

Blue_MiSfit

20th March 2020, 05:13

Probably 2:2:2:4 pulldown, unless you see a ton of aliasing, in which case it is indeed 3:2 but that would actually be harder.

huhn

20th March 2020, 05:42

is called 3:2 but with progressive frames.

i didn't make these names up

SeeMoreDigital

20th March 2020, 10:26

Many modern TV's, especially 'smart' TV's are able to automatically adjust their panels frequency/refresh rate to match the frequency of source content.

However (unless things have changed in recent years), computer graphics cards puke out a fixed frequency/refresh rate - which would have to be manually adjusted (if supported) to match the frequency of source content.

That being said, there's way too much content out there that's been poorly encoded and incorrectly flagged. So it's always good practice to check the source content for errors!

EDIT: It may also be worth pointing out that 24Hz (24fps) encoded content is actually pretty rare, even on UHD disc's. Indeed, most (progressive encoded) movie content runs at 23.976fps (ie: 23.976Hz). And if you force content encoded at 23.976fps to be displayed at 24Hz, it introduces other issues ;)

kolak

20th March 2020, 11:15

TVs always (well at least in last 20 years) been able to switch to "source native" fps, including 23.976p (as long as supported). This is what most monitors are unable to do, so they're not very good for watching movies.
Modern TVs quite often do multiple of native fps, or now frame interpolation (which always leaves some artefacts).
Best way of watching 24p is black frame insertion and running at eg. 72Hz or 120Hz (this is what happens at cinemas). Some TVs do it. Old Pioneer Kuro used 72Hz for 24p source and it worked very well.

If TV is trying to display 24p source at 60Hz then it's crap TV :)

huhn

20th March 2020, 12:35

If TV is trying to display 24p source at 60Hz then it's crap TV :)

how helpful.
the number of these TV is very high and even present in expensive close to flag ship TVs because how do you display 24p on a fixed 60 HZ panel?

wonkey_monkey

20th March 2020, 15:17

how helpful.
the number of these TV is very high and even present in expensive close to flag ship TVs because how do you display 24p on a fixed 60 HZ panel?

By not using a fixed 60Hz panel.

Asmodian

20th March 2020, 16:14

It is surprising how many fairly high end TVs from the last few years do use fixed 60 Hz panels. :(

wonkey_monkey

20th March 2020, 17:41

Maybe that's a US thing. A lot of them still don't support PAL, to the best of my knowledge.

Given that European TVs have to look good at 50Hz anyway, maybe they're more likely to be multi frequency.

huhn

20th March 2020, 17:48

nothing todo with that.
there are just a lot of panels that are limited to 60 HZ but they can do 50 Hz just fine.

wonkey_monkey

20th March 2020, 18:33

nothing todo with that.
there are just a lot of panels that are limited to 60 HZ but they can do 50 Hz just fine.

A panel that's fixed to 60Hz (if that's what you mean by limited) can't do 50 Hz "just fine" any more than it can do 24Hz (i.e. it could possibly do it, but only badly).

Last I heard, most US TVs still won't handle 50Hz signals at all, "just fine" or not.

huhn

20th March 2020, 19:43

and i read (panel specs included)and tested this far to much.

50 is not an issue it can be disabled by design but the panel doesn't have an issues which that they use the same panels in the eu and the USA.
are there cheap panels that can't do sure the top 5 panel producer panels with 50/60 hz.

sony fixed this issue they can do 24p with 60 panels the same 60 hz panels as other menufacture they don't produce LCD (they have a professional RGB OLED fab but ignore this) if they figured out doing 48 is not far from 50 or some thing like that i don't know that just how it is most TV with a 60 Hz panel can't do 24p there is no good reason for that but that's reality.

Asmodian

20th March 2020, 20:04

For LCDs refreshing at 24Hz can be technically bad. They cannot hold the liquid crystal in one orientation long term so you get apparent flicker as the pixels drift and then snap back at the next refresh. Of course, you could use 48Hz with frame doubling because most LCDs don't drift much in 21ms but even that could be too slow for a particular panel. It is also more expensive to support more refresh rates because you need to tune the refresh electronics for each refresh rate, requiring a better controller and more work up front. Not much more expensive today but you do have to spend something to support each refresh rate. :p

That said, I suspect most TVs don't that support 50Hz today could but don't as a simple region locking mechanism.

kolak

21st March 2020, 00:55

how helpful.
the number of these TV is very high and even present in expensive close to flag ship TVs because how do you display 24p on a fixed 60 HZ panel?

https://www.rtings.com/tv/tests/motion/24p

kolak

21st March 2020, 01:38

That said, I suspect most TVs don't that support 50Hz today could but don't as a simple region locking mechanism.

Nothing more than "politics".
Europe had all fps support for very long time now.

huhn

21st March 2020, 02:49

2018 was a bad year to buy a TV.

wonkey_monkey

21st March 2020, 10:11

Overall, 24p judder is not a major problem; most people will never even notice it.

True, possibly because Americans have been used to 24p judder since the days of CRTs and 3:2 pulldown.

Edit: there's a neat test on that page where they send an alternating 24p signal to the screen and take a long exposure photograph. If there is judder, it shows up in the photo as a bias towards one of the two frames. Neat!

huhn

21st March 2020, 13:43

why someone will ever need such a test to see something obvious like this is beyond me.

and there are other way to test this beside using additional hardware.

wonkey_monkey

21st March 2020, 14:01

Because it's not obvious to everyone.

Stereodude

21st March 2020, 15:27

2018 was a bad year to buy a TV.
Why do you say that? There were some very fine TVs sold in 2018.

For LCDs refreshing at 24Hz can be technically bad. They cannot hold the liquid crystal in one orientation long term so you get apparent flicker as the pixels drift and then snap back at the next refresh. Of course, you could use 48Hz with frame doubling because most LCDs don't drift much in 21ms but even that could be too slow for a particular panel.
That's not really true. The fluid is effectively used as a capacitor that holds the transistor in the state set by the panel drivers. The combination will hold the for quite a while (in terms of ms). It takes seconds for the image to fade if you stop refreshing the transistors.

It is also more expensive to support more refresh rates because you need to tune the refresh electronics for each refresh rate, requiring a better controller and more work up front. Not much more expensive today but you do have to spend something to support each refresh rate. :p
That's why they refresh the panel at 120Hz or 240Hz in good LCD TVs. They're not changing the actual drive rate for the panel much. All expected North American content is a multiple of those that divides in evenly into 120Hz.

That said, I suspect most TVs don't that support 50Hz today could but don't as a simple region locking mechanism.
What do you mean by support? I can input p25 and p50 into my US model LCD Sony TV. They are supported frame rates. I haven't bothered to confirm if it switches the panel drive to 100Hz. It wouldn't surprise me if it does. The European model of the same TV has to support p24 properly in addition to 50Hz content so it has to switch between 100Hz and 120Hz drive.

Because it's not obvious to everyone.
It pretty much is if you put two displays side by side. One with a 60Hz refresh rate and one with a refresh rate that's a multiple of 24Hz and show content with motion and pans in them they will quickly realize they don't look the same if told to compare them. They probably won't be able to tell you why, but they will see the difference.

huhn

21st March 2020, 15:43

because in 2018 samsung didn't produce a lot of 120 HZ panels and samsung is pretty much the biggest producer of VA panels leaving you with mostly 120 Hz IPS.

does that mean all TV are bad? no clue why you would come to the conclusion.

SeeMoreDigital

21st March 2020, 15:56

@markfilipak,

Out of interest... What device are you using to play your media files? And what's your Sharp TV's model number?

Asmodian

23rd March 2020, 05:49

That's not really true. The fluid is effectively used as a capacitor that holds the transistor in the state set by the panel drivers. The combination will hold the for quite a while (in terms of ms). It takes seconds for the image to fade if you stop refreshing the transistors.

Lots of the early VRR monitors had this issue. When the frame rate drops too low they flicker and it was solved by automatically refreshing the display twice when at low frame rates. The image is still there, the pixels only drift slightly, but it is enough to notice it frame to frame below 30-40 Hz, at least with many current LCD panels.

What do you mean by support? I can input p25 and p50 into my US model LCD Sony TV. They are supported frame rates. I haven't bothered to confirm if it switches the panel drive to 100Hz. It wouldn't surprise me if it does. The European model of the same TV has to support p24 properly in addition to 50Hz content so it has to switch between 100Hz and 120Hz drive.

I think most do, my recent LGs have supported 50Hz properly. Just some don't. :p

SeeMoreDigital

23rd March 2020, 09:59

I think most do, my recent LGs have supported 50Hz properly. Just some don't. :pYes they do...

Asmodian

23rd March 2020, 20:51

Yes they do...

You saying all TVs support 50Hz? Are you sure? :confused:

Very recent TVs do seem to support 50Hz most of the time but I would still not assume they all do. Maybe it is simply very cheap ones that don't care, and not some region locking nonsense. Using refresh rate support for region locking is hopefully out of date today.

SeeMoreDigital

23rd March 2020, 21:00

You saying all TVs support 50Hz? Are you sure? :confused:

Very recent TVs do seem to support 50Hz most of the time but I would still not assume they all do. Maybe it is simply very cheap ones that don't care, and not some region locking nonsense. That idea is hopefully be out of date today.All TV's in Europe support 50Hz (25 progressive frames and 50 interlaced fields per second)...

Asmodian

24th March 2020, 00:40

Well, of course! I was only talking about US TVs. Region locking by not supporting 50 Hz wouldn't make any sense with TVs sold in Europe. :confused:

SeeMoreDigital

24th March 2020, 09:04

Well, of course! I was only talking about US TVs. Region locking by not supporting 50 Hz wouldn't make any sense with TVs sold in Europe. :confused:As far as I know... All 'smart' Panasonic and LG televisions sold worldwide are capable of supporting 50Hz. Although the feature might be locked out and will require a visit to the service menu.

microchip8

24th March 2020, 09:51

I have an el cheapo Panasonic TV with an Innolux MVA panel. My NV Shield is set to 24 FPS and when I switch to it, my TV reports 24 Hz. Not sure whether it is true 24 Hz or it upconverts. Regardless, all looks fine here

huhn

24th March 2020, 10:25

panasonic well that's easy to test.

just actived pure direct mode and it can't do 24 HZ correctly anymore that's by design don't ask me why.

cheap version are sometimes just that brand in name but produce by someone else but still relative easy test.

there are other ways to test this but i'm not going into that.

microchip8

24th March 2020, 10:31

I know that the budget models are produced by the Turkish Vestel but mine is actually made by Panasonic itself in the Czech Republic. I do not use Pure/Pixel Direct as it makes the picture worse. I'm not too concerned with doing native 24 Hz or not. As long as it looks good to me, I'm happy :)

Stereodude

24th March 2020, 13:23

You saying all TVs support 50Hz? Are you sure? :confused:

Very recent TVs do seem to support 50Hz most of the time but I would still not assume they all do. Maybe it is simply very cheap ones that don't care, and not some region locking nonsense. Using refresh rate support for region locking is hopefully out of date today.
You've yet to define what "support" means in the context of your usage. Is it simply take the format on the input and put an image on the screen, or take the format on the input and display it at a refresh rate that is a multiple of 50Hz?

Asmodian

24th March 2020, 18:45

I meant accept the format as input and have an entry for it in their EDID. Sorry, I didn't think some TVs lacking support for 50Hz would be controversial. There used to be many TVs sold in the US that would not accept a 50 Hz signal at all, no attempt to display an image when provided with a 50Hz signal. Maybe this is no longer true, and all TVs sold in the US support 50Hz input, but I wouldn't assume that without first making sure if you need 50Hz. Historically 50 Hz support has been surprisingly bad in the US.

On that same note, I also would not be surprised if some TVs that do support 50Hz input end up displaying it with a 60 or 120 Hz refresh rate. I don't have any examples of this though, hopefully it isn't true.

kolak

24th March 2020, 20:50

Stereodude

25th March 2020, 01:45

I may be wrong, but a panel with eg. 120Hz max refresh rate is not fixed to it (or doesn't have to). It can operate at anything lower as well. It's up to manufacture to give such an ability or not. It's even more true for monitors which support adaptive sync. If I'm correct this seems to be coming to TVs as well (not only gaming monitors).
50Hz in USA use to be almost non-existing. No idea how it's now.
It's still non-existent for normal people in the US. I only have it from some concert Blu-rays that were shot as 1080p25 and converted to 1080i60 that I restored back to 1080p25.

SeeMoreDigital

25th March 2020, 11:09

It's still non-existent for normal people in the US. I only have it from some concert Blu-rays that were shot as 1080p25 and converted to 1080i60 that I restored back to 1080p25.
If I was a conspiracy theorist, I would postulate that way back in the DVD days, TV's (and players) destined for the North American NTSC market were locked out of PAL 50Hz support, so they could not take advantage of the (technically) 20% improvement in picture quality over their NTSC counterparts!

The organisations controlling the development and distribution of DVD including how their images are transported from player to display, were and still are... pretty anal!

kolak

25th March 2020, 12:40

It's obvious it's all down to politics and money. Probably Hollywood studios are behind it.

hello_hello

26th March 2020, 09:36

Nothing more than "politics".
Europe had all fps support for very long time now.

I'm in PAL-land (Australia) and I think every Bluray player and TV I've come across is 60Hz "at heart", but capable of 50Hz, or the TV's in NTSC land are 60Hz, with 50Hz disabled, however you want to look at it.

Both Bluray players here (Sony and Samsung) display their own menus at 60Hz. One only switches the TV to 50Hz when playing a 25fps disc, while the other is also clever enough to switch the TV to 50Hz when playing 25fps video via USB. I'm not sure which refresh rate the TV uses when playing video via it's internal media player. I've never tested it but most of the video I use it for is 23.976fps/24fps anyway.

My LCD computer monitor can accept either a 60Hz or 50Hz input.

NTSC support has been common for so long, that back when DVD rentals were a thing, I'd occasionally rent a DVD and not realise it was NTSC until I looked more closely at home, but even my old CRT could switch to "NTSC mode" and the DVD player didn't care.

kolak

26th March 2020, 11:06

Europe is the same, but USA is not. Their TVs (not players) don't really support 50Hz.

markfilipak

4th February 2021, 02:13

@markfilipak,

Out of interest... What device are you using to play your media files? And what's your Sharp TV's model number?

Sorry to take so long to reply (I've not been able to figure out doom9 and I don't get notifications).

I play via MPV running in Win10. The Sharp TV is connected via NVIDIA driven DisplayPort. The TV model is LC-42LB261U.

markfilipak

9th October 2021, 21:06

Sorry for getting really technical but this is a really technical subject.

If you're tired of seeing crap video and you find that my "best possible video" obsession interests you... I need your support trying to pry details out of the various project developers. There's power in numbers. Contact me here or via PM.

KEY: (In lieu of useless terms like '30i' and '24p'...)
KEY: "fps" means "frames-per-second"; "pps" means "pictures-per-second".
23.9fps[24pps] is BD/DVD cinema, progressive or soft telecined, ripped from disc [note 1].
59.9fps[2-2-2-4[24pps]] is my best guess how my TV displays 23.9fps[24pps] [note 2].
24fps[24pps] is 23.9fps[24pps] forced to theater frame rate/running time [note 3].
60fps[60pps] is 24fps[24pps] with interframe synthesis via 2-to-5 mv interpolation [note 4].
120fps[120pps] is 24fps[24pps] with interframe synthesis via 1-to-5 mv interpolation [note 5].

[note 1] 24pps is what's seen in theaters [note 6]; DVDs/BDs slow that down by 0.1% [note 7].
[note 2] 2-2-2-4 pull-down by the TV (...by appearance, the TV doesn't disclose anything).
[note 3] Force timebase & presentation time stamps via ffmpeg 'settb=expr=1/24,setpts=expr=N'.
[note 4] Motion vector interpolation synthesizes interframes & interframe pictures.
[note 5] Even better interframe synthesis due to integer (i.e. 5x, not 2.5x) interpolation.
[note 6] "Better" theaters triple-shutter to 72fps[24pps] but the picture rate remains 24pps.
[note 7] Slowdown: 24fps-to-24/1.001fps (so video can be telecined to NTSC 29.9fps ...yuck).

My Sharp 2K-TV,
1, Converts 23.9fps[24pps] inputs to 59.9fps[2-2-2-4[24pps]] display -- creates telecine judder;
2, Smooths (fuzzes) 59.9fps[2-3[24pps]] inputs -- less telecine judder but creates combing;
3, Displays 60fps[60pps] incredibly smoothly -- no judder, no combing;
4, Apparently drops alternate frames (120fps -> 60fps) without damaging the TV.

What does your TV do? How can you discover what your TV does? What's 'best' for all TVs?

FranceBB

9th October 2021, 23:02

What does your TV do?

Hi-end Samsung TVs from 2009 onwards do the following:

Input: 23.976p -> Linear Interpolation to 48fps + blending to 60p

Input: 29.970 telecined with 3:2 pulldown -> detects the telecine -> IVTC to 23.976p -> Linear Interpolation to 48fps + blending to 60p

Input: 29.970i (truly interlaced like for sports) -> bob to 60p

Input: 29.970p -> Linear Interpolation to 60p

Any other framerate set in between result in the TV not understanding what's going on and just leaving things as they are. For instance if you were to transmit a signal with let's say 28fps, it will display it as it is, resulting in stuttering etc.

What about 25p then? Well, if the TV is set to 60Hz, it doesn't detect it and just outputs the same, however if the TV is set to 50Hz it detects it and performs linear interpolation to 50p.

A note about linear interpolation: I've noticed that linear interpolation is quite good, but there are some artifacts, however those are limited. What I think happens underneath is that when the TV just doesn't know, it performs blending instead of linear interpolation, hence trying to limit the times in which linear interpolation results in artifacts.

Of course, the vast majority of contents I watch are PAL 'cause I live in PAL land and the TV is set to 50Hz, therefore what happens is that I always receive a 25i signal, but while for sports it's a real 25i signal that has to be bobbed to 50p and then displayed (and the TV does just that), for movies and TV Series it's actually a 25p flagged as 25i, therefore the TV detects that it's actually progressive and treats it as progressive (i.e it applies linear interpolation to 50p). There have been just a few times in which this didn't work out: you see, even though the content might be progressive, sometimes there are messages in a ticker showing up in the lower part of the screen and those messages are of course interlaced 'cause the whole stream is supposed to be interlaced, so what happens is that sometimes the TV detects it, switches to bobbing mode and you see the text moving fine but the whole scene stutter ('cause now you have those frames duplicated), and sometimes it doesn't and it keeps treating it as progressive and you see the text in the lower part of the screen being displayed as an interlaced mess.

wonkey_monkey

10th October 2021, 00:44

When you say "linear interpolation" are you talking about "smooth motion" settings and such? I.e. things no sane person would turn on in the first place? ;)

Input: 23.976p -> Linear Interpolation to 48fps + blending to 60p

That just sounds like the worst of both worlds...

markfilipak

10th October 2021, 03:54

When you say "linear interpolation" are you talking about "smooth motion" settings and such? I.e. things no sane person would turn on in the first place? ;)

That just sounds like the worst of both worlds...
@wonkey_monkey,

I'm with you. 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. Either that or, if the input is from a player or computer over HDMI or DisplayPort, then the TV's input is definitely raw frames. So, FranceBB must mean pixel interpolation (or maybe, just frame doubling) to 47.9fps and then 2-3 telecine to 59.9fps -- Is that right, FranceBB?

My Sharp has "smooth motion" and it's awful. I turned it off the first time I powered it up.

markfilipak

10th October 2021, 04:41

Hi-end Samsung TVs from 2009 onwards do the following:

Input: 23.976p -> Linear Interpolation to 48fps + blending to 60p

Input: 29.970 telecined with 3:2 pulldown -> detects the telecine -> IVTC to 23.976p -> Linear Interpolation to 48fps + blending to 60p
Blending? Really?

Input: 29.970i (truly interlaced like for sports) -> bob to 60p
Try this: separate the 29.9fps[59.9sps] fields to make two, 29.9fps[29.9pps] half-picture streams -- it doesn't matter whether the source stream is TFF or BFF -- then motion vector interpolate each half-picture stream separately to 119.8fps[119.8pps] (that's 4x), then delay the 2nd stream by 2 frames, then bob the first 2 frames of the 1st stream and weave the 2 streams together to form full-sized, 119.8fps[119.8pps] (progressive) frames. The 2nd half-picture stream delay is to time-align it's first frame (which is an original frame) with the 3rd frame of the 1st half-picture stream (which is a synthesized frame that coincides in time). Thereafter, each original field (top or bottom) will pair with a synthesized, time-aligned field (bottom or top) The result is seemingly 'live' -- like you're viewing reality -- and makes bob look absolutely 'mushy'. You can leave the result as 119.8fps[119.8pps] or drop it to 59.9fps[59.9pps].

Input: 29.970p -> Linear Interpolation to 60p
May I ask: For any of the above, how do you know that's what the TV does? Does it tell you? My TV tells me nothing and the manual tells me next to nothing (and in unknown, bogus marketing terms).

Any other framerate set in between result in the TV not understanding what's going on and just leaving things as they are. For instance if you were to transmit a signal with let's say 28fps, it will display it as it is, resulting in stuttering etc.
Well, 28fps that actually displays at 28fps will not stutter, so your TV must be doing some sort of telecine.

What about 25p then? Well, if the TV is set to 60Hz, it doesn't detect it and just outputs the same, however if the TV is set to 50Hz it detects it and performs linear interpolation to 50p.

A note about linear interpolation: I've noticed that linear interpolation is quite good, but there are some artifacts ...
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?

The reason I'm so interested is that I'm considering buying a new TV and the marketing material just doesn't reveal what TVs actually do.

Thanks for your contribution and your thoughts and feel free to clarify or ask questions.

--Mark.

markfilipak

10th October 2021, 05:07

http://tiny.cc/cx02hz

You're a pro! Well, try the field trick I outlined using a real-time interpolator (maybe, SVP) and see what you get. I've found that, for the same codec, the field trick results in a stream that not only looks fantastic, but it's 1/6 to 1/8 the size (6x to 8x the bps) even for placebo transcodes. I was greatly surprised and amazed to say the least!

markfilipak

10th October 2021, 06:16

@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

10th October 2021, 07:49

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

10th October 2021, 14:09

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

10th October 2021, 18:38

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

10th October 2021, 18:58

... 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

10th October 2021, 19:03

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

10th October 2021, 22:00

"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

11th October 2021, 00:19

@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

11th October 2021, 06:56

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

11th October 2021, 16:53

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

20th October 2021, 06:25

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

Is there any more info on it?

huhn

20th October 2021, 09:28

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

20th October 2021, 10:26

"Can't frame Interpolated"?

Can you please explain what are you talking about

markfilipak

20th October 2021, 16:00

"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

20th October 2021, 19:27

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

ognirats

20th October 2021, 19:33

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

20th October 2021, 19:47

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

21st October 2021, 04:11

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

21st October 2021, 04:17

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

21st October 2021, 04:34

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

21st October 2021, 07:58

https://imgur.com/a/FXevmEn

https://imgur.com/a/M0UH3rW

markfilipak

21st October 2021, 08:56

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

21st October 2021, 10:57

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

21st October 2021, 10:59

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.