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Old 19th March 2020, 02:27   #1  |  Link
markfilipak
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Survey: 60Hz TVs running at 24Hz

It's not a secret that Blu-ray movies look better on 24Hz TVs. What surprised me was, though my TV's manual says it runs solely at 60Hz, and though I could connect via HDMI under Windows solely at 60Hz, I can switch my Sharp TV to 24Hz via a NVIDIA utility! ...And it does look better.

Are all so-called 60Hz TVs capable of 24Hz video display? What's your experience been?

Please respond to this survey, even if you don't know. It will help survey coverage.

If you want to know how I did it, kindly email off-list via private message so that this survey space stays simple.

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Old 19th March 2020, 02:47   #2  |  Link
huhn
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pretty much all sony 60 HZ tvs are able to present 24 hz correctly all 60 HZ Tv are able to accept this type of signal but they usually unable to display them correctly which is called 3:2 judder.

BTW. because you can't select 120 hz doesn't mean the panel is run at that refreshrate.

there is a very easy test to check if a panel is 120 hz send 60 HZ and try to enable motion interpolation if it works by giving you a horrific image it's pretty much proven that the panel is 120 HZ.
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Old 19th March 2020, 04:31   #3  |  Link
markfilipak
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pretty much all sony 60 HZ tvs are able to present 24 hz correctly all 60 HZ Tv are able to accept this type of signal but they usually unable to display them correctly which is called 3:2 judder.
That's upconverting to 60p. It's not 24p.

So, Sony 60Hz (or 120Hz) TV's do not play 24p, is that what you say?
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Old 19th March 2020, 05:07   #4  |  Link
huhn
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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.

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

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That's upconverting to 60p. It's not 24p.
don't tell me that tell that them.
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Old 19th March 2020, 06:44   #5  |  Link
markfilipak
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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).
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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.
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Old 20th March 2020, 05:13   #6  |  Link
Blue_MiSfit
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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.
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Old 20th March 2020, 05:42   #7  |  Link
huhn
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is called 3:2 but with progressive frames.

i didn't make these names up
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Old 20th March 2020, 10:26   #8  |  Link
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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
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Old 20th March 2020, 11:15   #9  |  Link
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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

Last edited by kolak; 20th March 2020 at 11:21.
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Old 20th March 2020, 12:35   #10  |  Link
huhn
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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?
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Old 20th March 2020, 16:14   #11  |  Link
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It is surprising how many fairly high end TVs from the last few years do use fixed 60 Hz panels.
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Old 20th March 2020, 17:41   #12  |  Link
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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.
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Old 20th March 2020, 17:48   #13  |  Link
huhn
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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.
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Old 20th March 2020, 18:33   #14  |  Link
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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.
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Old 20th March 2020, 19:43   #15  |  Link
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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.
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Old 20th March 2020, 20:04   #16  |  Link
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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.

That said, I suspect most TVs don't that support 50Hz today could but don't as a simple region locking mechanism.
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Old 21st March 2020, 01:38   #17  |  Link
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Quote:
Originally Posted by Asmodian View Post

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.
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Old 21st March 2020, 02:49   #18  |  Link
huhn
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2018 was a bad year to buy a TV.
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Old 26th March 2020, 09:36   #19  |  Link
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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.

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Old 26th March 2020, 11:06   #20  |  Link
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Europe is the same, but USA is not. Their TVs (not players) don't really support 50Hz.
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