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Old 28th October 2011, 09:41   #1  |  Link
madhatter300871
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Do UK bluray players apply telecine ?

Hi

Question : Most (not all I know) bluray titles in the UK are presented at 23.976fps. Do bluray players speed up playback to 25fps, or do they apply telecine and hence send 29.97, or do they play at 23.976 and hope the TV can deal with it ? If the TV does deal with it, how ?

I have searched around for answers, I have found some but I'm still just ever so slightly confused.

The reason I ask is when that my projector can accept (according to the manual) 50hz/60hz signals at varying resolutions. The only way I can get 100% smooth playback without any hint of judder is to speed up the content to 25fps. If I don't playback is still very nice but there is judder. I have a HTPC.

I have created custom resolutions for my Nvidia card and the projector accepts them and does indeed display said refresh rate in it's info panel. I have tried 72Hz, 24Hz, 48Hz, both progressive and interlaced and just can't seem to remove the judder. I am presuming this is because 23.976 is not an exact multiple of 72/24/48.

Why oh why oh why are blurays presented in 23.976 fps, why not 25fps for the UK like DVDs are ? Why must the industry make things complicated ..... sigh, rant over

Hope someone can point me in the right direction.
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Old 28th October 2011, 16:39   #2  |  Link
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I'm not familiar with BluRay players but I very much doubt they can do a real time speed up. As always, when this whole thing was done, PAL, although used by 80% of the world (or so), had to take the shortcomings.
Yes, it is true, 23.976 is pretty much exactly the film's original framrate and speed, but it is indeed very incompatible with the domestic PAL refresh rate of 50 Hz while for NTSC it's not a big deal — to have 59.94 Hz the regular 3:2 pulldown pattern is simply applied... This can happen for analog SD output as well as via HDMI in 1080p, in any case, 60 Hz* is no problem with 23.976 BluRays (yes, natually it is not stutter free like speed up 25 fps is but it is hardly noticable). With PAL, without the speed up, you have two stutters per second because 23.976 are repeated so that 50 Hz output is archived. Actually this is one of the two ways to transfer film to PAL but the speed up method was used with 99% of all DVDs because it gives stutter free motion.

*whenever I say 60 Hz I mean 59.94 Hz

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Why oh why oh why are blurays presented in 23.976 fps, why not 25fps for the UK like DVDs are ? Why must the industry make things complicated
Yeah, I agree with you there. Although most people probably wouldn't. I don't think the speed up is a drawback if done right and it would keep the comptabibility with PAL. Just think of this: if you wanted to make a PAL DVD copy of a BluRay with 23.976...whoa that would get nasty, lot's of work.


Anyway, try to set the refresh rate to an exact multiple of 23.976 (more precisely it is 24000/1001). Maybe try 71.928 Hz

Last edited by TheSkiller; 28th October 2011 at 16:46.
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Old 28th October 2011, 17:13   #3  |  Link
madhatter300871
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Thanks for the reply.

Yes, I'll try setting that refresh rate but to be honest, what I might end up doing do is re-encode the audio and apply a rate change then remux into mkv at 25fps.

Hmmmm, or maybe buy a projector with native 24p support .... no, not likely just yet lol

Last edited by madhatter300871; 28th October 2011 at 17:20.
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Old 28th October 2011, 18:41   #4  |  Link
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AFAIK they can change the resolution only (but not always). The TV must understand both the fps and the framesize (EDID), if not, the player can try various settings (including 24p->50/60p if on-board) until both agree.
My player can switch from 24p to 60p and from 50i to 50p if needed, but I can't force it to do any combination I want (only the presets it has, not too many anyway, since Pioneer dropped the 720p support in favour of 1080p, a bad move for the owners of older projectors).
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Old 29th October 2011, 10:19   #5  |  Link
madhatter300871
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My projector can do 1024x768 @ 72Hz, but who wants to play a HD movie at 1024x768 !! My PC will scale it down to 1024x768 then the projector will scale it back up to 1280x720 (native resolution).

Am I correct in assuming the following :-

1. Movies can be presented at any frame rate but the most common ones are 23.976p, 24p, 25p, 29.97p, 30p, 50i, 60i
2. Movies can be presented in any resolution, but the most common commercial ones are (PAL) 720x576, 1280x720, 1920x1080
3. Displays can be capable of accepting many refresh rates, but the most common ones are 24Hz, 50Hz, 60Hz. (Also many more for PC connection).
4. For 100% smooth playback with no judder the movie frame rate MUST be a multiple of the display refresh rate.

Question : When a display has 24p support, does this mean 24p or 23.976p. If it means 24p, will 23.976p movies judder (and vice versa).

Question : If I do set my projector to 1024x768@72Hz, will my 23.976fps movie judder (its not 24p is it, so its not an exact multiple of 72).
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Old 29th October 2011, 11:16   #6  |  Link
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Quote:
Originally Posted by madhatter300871 View Post
Question : When a display has 24p support, does this mean 24p or 23.976p. If it means 24p, will 23.976p movies judder (and vice versa).
I'm pretty sure a display capable of 24p will display both 23.976 and 24.000 natively without judder. Other opinions?

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If I do set my projector to 1024x768@72Hz, will my 23.976fps movie judder (its not 24p is it, so its not an exact multiple of 72).
Yes, there should be a rather slight judder every 111 film-frames (about every 4.6 seconds). Think of it like this: every 4.6 sec the currently displayed picture will be shown four times instead of three times like all the other. If this wouldn't happen the video would run of sync with the audio. Since the difference is very small a slight speed up of the audio would help to make the video play judder free at 24.000 fps with 72 Hz output. You should try Reclock. It is a directshow filter (real time during playback) and it does exactly that. Chances are good you will get a 100% judder free output of 23.976 sources on 72 Hz. A side note: even if you set the output of your GPU to 72 Hz is mostly never exactly 72.000 Hz for whatever reason. In my experience is is slightly less most of the time. It is hard to check though as most display devices dont show fractions of Hz. It should be no problem nevertheless, Reclock adapts to any refresh rate.
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Old 30th October 2011, 18:35   #7  |  Link
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Yes I have played with reclock, problem there is I dont want my computer decoding my DTS/AC3 sources, I have an amp to do that. So I use reclock and I have it configured to bitstream the audio to the amp, the audio goes out of sync (as it would).

What I am now 'playing' with is just converting the audio and performing a speedup to match 25fps, then remuxing into an MKV and specifying 25fps.

I will have another play with reclock in case I have missed a trick.

I'll report back.
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Old 30th October 2011, 19:52   #8  |  Link
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Well ive played with reclock .... played with a custom resolution setting refresh rate to 71.928 (the PJ accepts it no problem). Playback is good, it is smoother, but its not perfect.

Ignoring audio for the moment, if i re-mux at 25fps its perfect, very very smooth indeed. I am left with the conclusion that my PJ is old (I have owned it for about 6 years), and it just doesn't support 24/23.976 very good. I suppose it is pre-bluray generation really.

So, 25p it is then. I'll backup my blurays to 25p, re-encode the audio (so unfortunatelly I'll lose DTS) and watch them on the PJ in 25p.

Audio is still awesome, just really wanted the DTS.
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Old 1st November 2011, 14:44   #9  |  Link
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Remember, anything in the TV world is either NTSC or PAL, so you will never have 24 Hz, 60 Hz, etc. You will have 23.976, 29.97, 59.94, etc. I don't care if someone thinks 24p means 24p, it ALWAYS means 24/1.001p. People who release their final material in non-standards are idiots (all the free Blender-made movies.) I wouldn't even be surprised if film's speed has been slowed down a long time ago to meet NTSC.
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Old 1st November 2011, 15:13   #10  |  Link
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I guess everyone else in the world must have been suckered in by this 1080p/24 thing....

According to Reclock, my video card is connected to the TV at 60.001Hz, so there's one exception to your theory.
When I use the Bluray player, the refresh rate changes to 50Hz for PAL video and 60Hz (well, 59.94 probably) for NTSC. Now my Bluray player supports 1080p/24 but the TV does not. If it did, would it just pretend to switch the refresh rate to 120Hz, or whatever's required for 1080/24p?
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Old 1st November 2011, 15:20   #11  |  Link
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He said NTSC or PAL. Your computer is neither, is just a computer. Computers doesn't have to obey NTSC/PAL/HDTV and so on, to this end there are special cards, that can not only provide the required fps, but also the correct chroma space and levels.
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Old 1st November 2011, 21:37   #12  |  Link
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So are you saying he's correct and 24p is a marketing myth or are you just arguing for the sake of it?
I know he said NTSC or PAL, but that doesn't prove there's no such thing as 24p mode. Isn't that the whole point of 24p mode.... it's not NTSC or PAL??

My TV itself supports 60Hz, 60Hz or 60Hz when a PC is connected to it via the VGA input, so it wouldn't matter how special the video card is. According to the manual (which gives very little technical information) only one of the TVs HDMI inputs should be used for connecting a PC, so even if I were to believe a video card doesn't provide the correct chroma space and levels, I'd be willing to theorise the PC inputs are designed to reproduce the picture properly according to the levels expected from a video card. It must be doing something right as the PC picture tends to look a little better than the same picture via the Bluray player.
TVs have had dedicated PC inputs for a long time, and as you said a PC isn't NTSC or PAL. Why does a Bluray player have to be if it supports 24p mode?

I guess that's another advantage of using a PC for playback. Reclock speeds 23.976fps video up to 24fps, so if my TV supported 24p mode (it doesn't) I'd probably be able to watch almost everything that way.
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Old 1st November 2011, 22:08   #13  |  Link
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Are you sure there is no such thing as 24p ? Are you sure it really implies 24000/1001 (or 24/1.001). i.e 23.976 ?

I have blurays that indicate on the packaging, and confirmed via mediainfo, that they have a frame rate of 24fps. I have some that have a frame rate of 23.976fps. I also have 1 that has a frame rate of 25fps.

I'm not arguing, I am genuinely a little confused here, hence I have began to play and test.

Not sure if this could be done, but could "we" contact the manufactures do you think, ask this question once and for all ? not sure who I would contact or if i would even get a sensible reply, any one think it is worth a go or are you all convinced that 24p really doesn't exist ?

P.S. Why cant UK blurays just be presented in 25fps just like our PAL DVDs, had no problem what so ever with them ! Oh it's all getting far to technical lol
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Old 1st November 2011, 23:00   #14  |  Link
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madhatter300871,
There's definitely 24fps Bluray discs. The idea being that if the player and TV both support 24p mode, the refresh rate of the TV will be an even multiple of the frame rate, theoretically resulting in smoother looking motion. I think the refresh rate used is usually 120Hz but I'm not exactly an expert on it. I'm not sure what happens if your TV doesn't support 24p mode, the player may just output at 23.976. Someone else might know the answer to that one.

Of course that doesn't mean NTSC (23.976fps) and PAL discs don't exist as obviously they do. When you play a PAL disc your TV should automatically switch to a 50Hz refresh rate, and for NTSC it's 60Hz (although some newer TVs have higher refresh rates, probably more to do with marketing than picture quality).

At this point in the thread we're discussion whether ramicio's contention that 24p mode isn't real and it's all just NTSC/PAL refresh rates is correct. Whether 24p mode makes a huge difference or not I don't know as my TV doesn't support it, but in theory it should eliminate the NTSC judder you get from trying to match 23.976fps with a 60Hz refresh rate.

I guess a lot of movies might be 24fps instead of 25fps because the former is the original frame rate and the latter is sped up and many purists don't like it. Personally I'm not that fussed, and at 25fps it takes less time to watch the same amount of movie.

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Old 2nd November 2011, 09:29   #15  |  Link
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Quote:
Originally Posted by hello_hello View Post
So are you saying he's correct and 24p is a marketing myth or are you just arguing for the sake of it?
I know he said NTSC or PAL, but that doesn't prove there's no such thing as 24p mode. Isn't that the whole point of 24p mode.... it's not NTSC or PAL??

My TV itself supports 60Hz, 60Hz or 60Hz when a PC is connected to it via the VGA input, so it wouldn't matter how special the video card is. According to the manual (which gives very little technical information) only one of the TVs HDMI inputs should be used for connecting a PC, so even if I were to believe a video card doesn't provide the correct chroma space and levels, I'd be willing to theorise the PC inputs are designed to reproduce the picture properly according to the levels expected from a video card. It must be doing something right as the PC picture tends to look a little better than the same picture via the Bluray player.
TVs have had dedicated PC inputs for a long time, and as you said a PC isn't NTSC or PAL. Why does a Bluray player have to be if it supports 24p mode?

I guess that's another advantage of using a PC for playback. Reclock speeds 23.976fps video up to 24fps, so if my TV supported 24p mode (it doesn't) I'd probably be able to watch almost everything that way.
I'm not arguing.
But you forget that only flatscreen TVs had special inputs for computer (notice the word special), so they can accommodate non-standard-for-TV fps like 60Hz or 72 or 75Hz. Most of LCDs sold could only be driven at 60Hz or more, and this was sold to people as a technical advance - this is what I call marketing , no matter what signal has been used, it was always resampled at 60Hz (or whatever the native fps of the panel was). Unless they relaxed the specs, a TV cannot/couldn't accept non-HDMI signals over a regular HDMI.
Each feature is licenced and that costs money so unless they have a reason to do they won't add features just to be there.
Apparently your logic is that a thing has some features, then these features are standard. Exemplia gratia if one/your BD-player has the ability to play MKV files, then MKV-playback is a standard feature of any BD-player and/or mentioned in the standard. Or if your TV can accept 72Hz signals on an input, then 72Hz is a standard feature of all TV sets worldwide.

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Originally Posted by madhatter300871 View Post
Are you sure there is no such thing as 24p ? Are you sure it really implies 24000/1001 (or 24/1.001). i.e 23.976 ?

I have blurays that indicate on the packaging, and confirmed via mediainfo, that they have a frame rate of 24fps. I have some that have a frame rate of 23.976fps. I also have 1 that has a frame rate of 25fps.
I've never seen any indication of 23.976 on the cover, only 24fps. I think they are afraid that mentioning 23.976 on the cover they could scare some misinformed people (those knowing about 24fps and cinema and stuff), or would make some others unsure (they "succeeded" with you) - not only it will take valuable space on the cover (they would rather prefer to fill in that space with legal warnings ), but who cares, it won't pose any problems to playback on ANY BD-player coupled on ANY TVset (provided the TV set understands natively 24fps, which was achieved by plasma only, now there are more and more LCDs that claims the same, well, unless they made progresses in the field, of which I am not aware, that 24fps support is only for inputs, while the panel is still driven at 60Hz, yes, for PAL TVs too).

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madhatter300871,
There's definitely 24fps Bluray discs. The idea being that if the player and TV both support 24p mode, the refresh rate of the TV will be an even multiple of the frame rate, theoretically resulting in smoother looking motion. I think the refresh rate used is usually 120Hz but I'm not exactly an expert on it. I'm not sure what happens if your TV doesn't support 24p mode, the player may just output at 23.976. Someone else might know the answer to that one.

Of course that doesn't mean NTSC (23.976fps) and PAL discs don't exist as obviously they do. When you play a PAL disc your TV should automatically switch to a 50Hz refresh rate, and for NTSC it's 60Hz (although some newer TVs have higher refresh rates, probably more to do with marketing than picture quality).

At this point in the thread we're discussion whether ramicio's contention that 24p mode isn't real and it's all just NTSC/PAL refresh rates is correct. Whether 24p mode makes a huge difference or not I don't know as my TV doesn't support it, but in theory it should eliminate the NTSC judder you get from trying to match 23.976fps with a 60Hz refresh rate.
24fps exists as a standard in the Blu-ray specs for HD content. There is no 24fps in the DVD specs, and 23.976 can be obtained by IVTC from the standardised 59.94i.
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Old 2nd November 2011, 10:08   #16  |  Link
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I'm not arguing.
But you forget that only flatscreen TVs had special inputs for computer (notice the word special), so they can accommodate non-standard-for-TV fps like 60Hz or 72 or 75Hz.
And now they accommodate 24p. I haven't forgotten anything... that was basically my point. What's yours?

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it won't pose any problems to playback on ANY BD-player coupled on ANY TVset (provided the TV set understands natively 24fps, which was achieved by plasma only, now there are more and more LCDs that claims the same, well, unless they made progresses in the field, of which I am not aware, that 24fps support is only for inputs, while the panel is still driven at 60Hz, yes, for PAL TVs too).
Seriously... so all these 24p TVs are just pretending to have higher refresh rates? And when I play a 25fps disc on my Bluray player and a refresh rate of 50Hz is displayed on the screen, it's only fooling? Why don't I still see judder when playing a 25fps video?
I know my TV doesn't have a 24p mode, but I can still play 24p discs while it uses a 60Hz refresh rate, so I can still also experience NTSC judder, but what about TVs which do have a 24p mode. How do they eliminate the judder if they're only pretending to have higher refresh rates but the screen refresh rate is still only 60hz?
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Old 2nd November 2011, 11:01   #17  |  Link
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It's only for the LCD technology, neither for plasma nor for CRT.
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Old 2nd November 2011, 12:02   #18  |  Link
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As far as I'm aware, there's now many LCDs which have higher screen refresh rates.
If I recall correctly, my ex's LCD TV defaults to a refresh rate of 72Hz when using the PC input. Why would it bother if the TV can only refresh the screen at 60Hz? All video cards are capable of 60Hz. I'd be willing to believe it's because the TV will actually refresh the display at 72Hz over some theory it's just a marketing gimmick and the TV really re-samples the input at 60Hz. How many TVs did you test in order to arrive at that conclusion?
My TV only accepts a 60Hz PC input. Is that because the screen only refreshes at 60Hz or do TV manufacturers get lazy when it comes to employing all the marketing gimmicks in all of their TVs?

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Unless they relaxed the specs, a TV cannot/couldn't accept non-HDMI signals over a regular HDMI.
What's non-HDMI about a higher refresh rate? Mentioning the HDMI specs might give the impression of knowledge, but does it actually mean anything?

Back to the 24p topic.... I've been doing a little research and there's one thing I haven't been able to clarify as yet.
Obviously there's 24fps Bluray discs, but many sites which explain the different frame/refresh rates also seem to use the term 24p interchangeably when referring to video with a 23.976 frame rate. I assume when a player plays 24p video while connected to a TV only capable of displaying NTSC the whole thing must happen at 23.976, but I can't establish which frame/refresh rates are used when the TV is 24p capable.... i.e. whether the video is displayed at 23.976 using a refresh rate which is an exact multiple of it, or at 24fps using a refresh rate which is also an exact multiple. I assume the refresh rate used for 24p must be some sort of standard?

Whichever way it works, I still don't believe there's no such thing as a real 24p mode. Unless it's a marketing gimmick which has fooled every reviewer of TVs on the planet, and every owner of 24p LCD TVs have been fooled into believing they no longer experience NTSC judder when playing 24p video. If a TV is 24p capable, then it'd have to be able to refresh the screen at a rate which is a multiple of 24 (usually 120Hz). Even if it turns out they really play the video at 23.976 and use a refresh rate which is a multiple of it instead, it doesn't really matter as it's the whole point of 24p.

24p in high definition disc formats
Both HD DVD and Blu-ray Disc support the 24p frame rate, but technical implementations of this mode are different among the two formats. Blu-ray Disc supports 24p with its native timing, while HD DVD uses 60i timing for 24p (replacing missing frames with "repeat field flags").

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Old 3rd November 2011, 07:03   #19  |  Link
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unless they made progresses in the field, of which I am not aware, that 24fps support is only for inputs, while the panel is still driven at 60Hz, yes, for PAL TVs too).
The big thing now is motion interpolation to a higher rate, like 120Hz LCD. On the showroom floor you see the full 120Hz with the soap opera effect. Take it home and you can turn off the interpolation while keeping the same refresh rate, achieving frame repetition from 24->120 instead.

This has been common for a few years now, though unluckily it was introduced after I bought my 60Hz panel...

http://www.youtube.com/watch?v=nuvoL54t8EY

There are at least 311 Blu-rays released with a frame rate of 24.000: http://www.cinemasquid.com/blu-ray/m...-frame-rate=24

This data comes from BDInfo, a tool that scans the file structure. The same info can be found here by using CTRL+F for 1080p24*.

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Old 3rd November 2011, 09:02   #20  |  Link
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As far as I'm aware, there's now many LCDs which have higher screen refresh rates.
That is irrelevant, of course they are, as I said and I have to repeat myself, unless technical advances in driving an LCD panel below 60Hz appear (not technical means to mask this effect, like motion interpolation as it was mentioned before), not LCD TV will be able to display pure 24Hz (or 23.976).
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What's non-HDMI about a higher refresh rate? Mentioning the HDMI specs might give the impression of knowledge, but does it actually mean anything?
Well I have access to these standards so I know what I'm talking about, as opposed to people that only deduct things.
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Back to the 24p topic.... I've been doing a little research and there's one thing I haven't been able to clarify as yet.
Obviously there's 24fps Bluray discs, but many sites which explain the different frame/refresh rates also seem to use the term 24p interchangeably when referring to video with a 23.976 frame rate. I assume when a player plays 24p video while connected to a TV only capable of displaying NTSC the whole thing must happen at 23.976, but I can't establish which frame/refresh rates are used when the TV is 24p capable.... i.e. whether the video is displayed at 23.976 using a refresh rate which is an exact multiple of it, or at 24fps using a refresh rate which is also an exact multiple. I assume the refresh rate used for 24p must be some sort of standard?

Whichever way it works, I still don't believe there's no such thing as a real 24p mode. Unless it's a marketing gimmick which has fooled every reviewer of TVs on the planet, and every owner of 24p LCD TVs have been fooled into believing they no longer experience NTSC judder when playing 24p video. If a TV is 24p capable, then it'd have to be able to refresh the screen at a rate which is a multiple of 24 (usually 120Hz). Even if it turns out they really play the video at 23.976 and use a refresh rate which is a multiple of it instead, it doesn't really matter as it's the whole point of 24p.

24p in high definition disc formats
Both HD DVD and Blu-ray Disc support the 24p frame rate, but technical implementations of this mode are different among the two formats. Blu-ray Disc supports 24p with its native timing, while HD DVD uses 60i timing for 24p (replacing missing frames with "repeat field flags").
It appears to be a huge confusion here when people talk about 24fps, NTSC, discs and so on.

Any TV is able to display SD signals (of the agreed norm) and HD signals (again of the agreed norm). The same is true for the players.

How they do it is the big question. Apparently, people targeted here only the TVs, fully forgetting the players.

But first the TVs. The "head" of the TV is the panel. Its properties dictates the design of the video processor. If the panel can be driven natively at 24fps (CRT, plasma, highly unlikely LCD) then the video proc can simply pass the 24fps signal to the driver. If the panel is driven at 60Hz ("NTSC" plasmas, "NTSC" CRTs, LCDs), then the video proc tries to fit the incoming 24fps (here includes 23.976 as well) into 60, 100, 120, 200, 240, 400 Hz etc. Various frame interpolation and motion compensation techniques have been developed to this end. The same is true for any other signal that doesn't fit the driving refresh rate of the panel, any signal, any standard, any input.
There are also players that couldn't do 24fps (first generations of Sharp, some Funais (and their OEMs) if I have to name names). In this case no matter whether the panel could do 24fps or not, the result was the same.
For SD, where everything was interlaced, it was the choice of output. For NTSC, it was possible to do the IVTC in the player or in the TV (some TVs could do this) - but this required YUV connections, since the regular connections could not be used for progressive video (there is no such thing as progressive NTSC or progressive PAL - using YUV/YCbCr was possible however to send progressive signals having luma and chroma and timings of PAL/NTSC). For PAL, it remained only the choice of doing the deinterlacing in the player or in the TV itself. The panel must have be driven at 25/50Hz, that's why the first generations of PAL LCDs looked so ugly, so they used to display only lizards, trees, flowers, static nature in general in HDTV in the showrooms, once one switched them to a sport channel, oh my god!
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