Do UK bluray players apply telecine ?

[madhatter300871]

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.

[TheSkiller]

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. :rolleyes:
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

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 complicatedYeah, 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. :rolleyes:


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

[madhatter300871]

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

[Ghitulescu]

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).

[madhatter300871]

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).

[TheSkiller]

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?

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 (http://www.videohelp.com/tools/ReClock-Directshow-Filter). 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.

[madhatter300871]

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.

[madhatter300871]

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.

[ramicio]

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.

[hello_hello]

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?

[Ghitulescu]

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.

[hello_hello]

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.

[madhatter300871]

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

[hello_hello]

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.

[Ghitulescu]

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.

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).

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.

[hello_hello]

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?

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?

[Ghitulescu]

It's only for the LCD technology, neither for plasma nor for CRT.

[hello_hello]

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?

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 (http://en.wikipedia.org/wiki/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").

[ChiDragon]

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/movies/specs?video-frame-rate=24

This data comes from BDInfo, a tool that scans the file structure. The same info can be found here (http://www.avsforum.com/avs-vb/showthread.php?t=1155731) by using CTRL+F for 1080p24*.

[Ghitulescu]

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).
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.
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 (http://en.wikipedia.org/wiki/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! :)

[hello_hello]

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).

Repeat yourself?? Who's referred to refresh rates of 24Hz? You certainly haven't, and I haven't, not once. I've always referred to refresh rates which are an even multiple of 24.
I've not followed all the various attempts at 24p but I'm pretty sure if there was a 24Hz refresh rate in any sort of TV it came and went fairly quickly because of the noticeable flicker. Same with 48Hz, I think. These days even Plasmas use higher refresh rates such as 96Hz.
As far as I'm aware even a movie projector flashes each frame on the screen twice, so why you think a TV has to refresh at 24Hz to be 24p is beyond me.

Well I have access to these standards so I know what I'm talking about, as opposed to people that only deduct things.

Well you've proved that not to be true on numerous occasions.
Once again, claiming to have access to the standards might make it sound like you know what you're talking about, but showing you really do is another matter.
I'll ask again.... when you said "Unless they relaxed the specs, a TV cannot/couldn't accept non-HDMI signals over a regular HDMI", what non-HDMI signals were you referring to in the context of this discussion?

It appears to be a huge confusion here when people talk about 24fps, NTSC, discs and so on.

There's no confusion here, and no need for a recap of the history of TVs according to Ghitulescu.
It's fairly simple. For a TV to support 24p mode it has to be able to use a refresh rate that's an even multiple of 24 and not 60i etc as ramicio claimed they do. The merits of which refresh rate, or the effectiveness of a TVs attempt to improve the picture with interpolated frames etc is irrelevant.
As I stated several times, that's the topic. If you want to alleviate any confusion, a good place to start would be with a recap of the point you're trying to make.

[madhatter300871]

Hi again.

I didn't mean to start an argument here .... :scared:

OK so from what I have been reading am I correct in making the following observations :-

1. 23.976fps and 24fps(24p) are different frame rates, one does not refer to the other. i.e. 24p is not just shorthand for 23.976.

2. For 100% judder free playback the display should have a refresh rate of an exact multiple of the movie fps.

3. A display might do some clever processing of the input signal (adding frames, interpolating frames, telecining or whatever) in order to match the movie fps.

4. A standalone player might also do some clever frame rate manipulation.

5. A PC does what you ask it to do. You can specify graphics card refresh rate, movie playback speed etc and so you should be able to at least match your graphics card refresh rate with your display refresh rate. This would still have to be an exact multiple of movie fps for 100% judder free playback.

6. LCD panels, be it on a TV or a projector, may well be driven at 60Hz but all I can really do is go by the details given in the manual. If it says it can do 72Hz or 96Hz or whatever I can only take that as so, I would not really have any idea what it is doing with the input signal before it is presented to the panel.

7. 'PAL' and 'NTSC' are TV formats and indicate a 50Hz and 60Hz respectively interlaced signal.

8. There is no such thing as PAL and NTSC in the HD world, although we can mimic their timings, luma and chroma.

9. In the NTSC analogue domain, 29.97Hz and 30Hz are different refresh rates, one does not refer to the other. i.e. 30Hz is not short hand for 29.97Hz.

10. In the NTSC analogue domain, 59.94Hz and 60Hz are different refresh rates, one does not refer to the other. i.e. 60Hz is not short hand for 59.94Hz.

11. Displays (my projector in particular) can more than likely accept more refresh rates using the VGA input than it can using the HDMI input. Reading the manual it seems that the HDMI input can accept 480i, 576i, 720p, 1080p, 1080i at 50Hz or 60Hz, the VGA input can accept a multitude or resolutions at frequencies up to 72Hz.

12. Referring to point 11, HDMI is not designed to accept the wide range of frequencies that VGA can. HDMI is for media playback whereas VGA is for PC connection. (Hmmm, bummer!)

So far the only solution that gives me 100% judder free playback (and I must say it seems like a much crisper image also, although I am now going goggle eyes doing these tests so that could be a placebo effect !!) is to play the movie at 25fps. I don't use reclock because something just isn't quite working right for my setup and I can't quite put my finger on it. I speed up and resample the audio off line and remux into an MKV specifying 25fps. I am very accustomed to the small pitch change as I have watched PAL DVDs all my life :D

Am I beginning to bark up the right tree here ?

Sorry to be a pain, I know this is all simple stuff for the Gurus. Just trying to make sure I'm getting this all correct.

I'm finding this discussion very interesting,hope you guys continue to help.

[Ghitulescu]

1. technically yes, in practice the studios won't mention 23.976 on the cover, just 24p
2. yes
3. not might but should (it's mandatory, otherwise it cannot display the video)
4. image enhancements, video processing etc.
5. there's no problem to match a monitor to a graphic cards, for 20 years or more all the monitors are multisynch, ie capable to match the fps of the graphic card. However, they won't accept any combination of display size and fps (DDC, EDID).
6. there's a trend to hide the technical details from the consumer. It also help hiding the facts that would contradict the marketing slogans or advertisements, and makes difficult a direct comparison to a similar device from a competitor (in the end the battle is decided by the "featuritis", not by quality).
7. technically no, but I used NTSC and PAL also in this sense
8. yes, NTSC and PAL are SDTV, what I said about "mimic" referred strictly to YUV and progressive video over analog connections
9. see 1.
10. see 1. and 9.
11. yes, because the VGA input is taylored for computer interfacing, and these may have tens even hundreds of video modes (as opposed to 2 for SDTV and several more for HDTV)
12. HDMI is a superset of DVI, so it will accept everything that DVI will. However, if used for video (BDplayer, HDTV-receiver etc.), it won't accept everything (some TVs have a HDMI-input labelled as PC, it will accept various PC video modes)

[hello_hello]

1. I think technically yes, although it probably doesn't mean it's not used that way. Way before HD I've seen progressive 23.976 DVDs referred to as 24p.

2. If referring to the judder caused by an uneven duplication of frames, then yes, a refresh rate of twice the display rate should eliminate it. That's not to say motion will necessarily look completely fluid, hence some TVs trying to be clever with interpolating frames.

3 & 4. I think it's usually the player which does the frame manipulation to match the refresh rate, with the exception of interpolated frames which I think would be the TV's domain. I could be wrong...

5. Basically yes, although a video card is normally only capable of specific refresh rates, so I assume a display would need to have dedicated PC inputs in order to match one or more of the refresh rates the video card is capable of. I don't actually know what happen if you tried to connect a 60Hz video card to a 59.94Hz display input. I've never tried it.

6. Until I see evidence to the contrary, I'm going with the theory that if a display can accept refresh rates other than 60Hz, it's because it's capable of refreshing at those other refresh rates. Maybe that's not always the case... I don't know.... but sometimes it pays to be sceptical about some of the "facts" offered here.

7. Yes, at least that's the way most people would refer to them.

8. Same as 7, I think.

9 & 10. I don't think any device uses a 29.970 or 30Hz refresh rate as such, and 60Hz is commonly used as shorthand for 59.94Hz. (When your manual says 50 and 60Hz, I wonder if it means 50 and 59.94Hz only, or whether 60Hz is okay too? Connecting PCs to devices that way is out of my range of experience)

11 & 12. Not 100% sure about that one. The earlier mention of HDMI specs in this thread is another one of those times I'm happy to be sceptical. It sounded like hot air. There's very little difference between a DVI signal and a HDMI signal. In fact if a video card has a DVI out you can usually add a DVI to HDMI adaptor to it. My TV has a dedicated PC-HDMI input marked HDMI/DVI. In my case it's probably only capable of 60Hz (I haven't tested it) but I'd be surprised if there's a specification which forbids HDMI from doing anything DVI can do. It'd be up to the capabilities of the device and what the manufacturer decides to implement.

[madhatter300871]

Did a bit more reading and found that NTSC field refresh frequency in black and white systems was exactly 60Hz, which off course matched the mains power frequency in the USA.

When colour was added the frequency was shifted slightly downward to 59.94 Hz to eliminate stationary dot patterns in the frequency difference between the sound and color carriers.

I did some more reading using wikipedia as my main source (I can hear you all groaning now !)

I have come to the following conclusion :-

1. NTSC refresh rate is 29.97 frames per second, 59.95 fields per second, hence 59.94Hz (actually its 60/1.001). This will often be referred to as 60Hz.

2. PAL refresh rate is 25 frames per second, 50 fields per second, hence 50Hz.

3. 24p does exist and is a real frame rate.

4. 23.976p does exist and is a real frame rate.

Looks like many film productions shoot 24 progressive frames per second (24p) and many TV productions shoot in 23.976 frames per second. Wikipedia also says :-

"As Charles Poynton explains, the 24 frame/s rate is not just a cinema standard, it is also "uniquely suited to conversion to both 50 Hz systems (through 2:2 pulldown, 4% fast) and 59.94 Hz systems (through 2:3 pulldown, 0.1% slow). Choosing a rate other than 24 frame/s would compromise this widely accepted method of conversion, and make it difficult for film producers to access international markets"

Cameras also exist that can shoot video at 50 fields per second and 59.94 fields per second.

I think if manufacturers and distributors stopped treating us as fools and just said when something was 24p, or 23.976p, or 59.94i or 50i or 25p etc then we would know exactly what we where dealing with. Dream on hey !

It also appears that many terms are, incorrectly, interchanged. Some manufacturers say 24 when they really mean 23.976, 60 when they really mean 59.94 or even 60 when they really mean 23.976 with 3:2 pulldown applied.

This leads me onto another question :-

Is it safe to trust mediainfo and tsmuxer and other such programs ? Do we think the frame rates they report are real ? Is it possible a container could report 24fps when really it means 23.976 ?

I can totally get my head around the different standards but just can't seem to have confidence in terminology used for devices. For example, I now am pretty damn certain NTSC refresh rates are 59.94Hz (but referred to as 60Hz for ease). But when my projector documentation says it accepts 50hz/60Hz input does it really mean 50Hz/59.94Hz ? I am guessing it must be .....

[ramicio]

Only a 120 Hz or a 240Hz panel can totally do away with judder from a 24 fps source. If the panel is 60 Hz, there will be judder, and I don't care what kind of fancy interpolation these companies try to pull out of their ass, it's going to always be 3:2 crap. These TV manufacturers really need to get on the ball of offering a 120Hz input. I don't know why the HDMI idiots keep insisting on ramping up resolutions, but they won't touch refresh rates. The bandwidth is there, it's just semantics in the standards that makes everything a pain in the ass. Feeding a TV a 24Hz signal from a PC is total crap.

[madhatter300871]

Feeding a TV a 24Hz signal from a PC is total crap.

This is the conclusion I have also come to. I think refresh rate is equally important as resolution, if not more so. For me, the judder is so obvious I now can't help but see it.

Still looks like my only solution for feeding my projector is to 'convert' to 25 frames per second, I genuinely can't notice the pitch increase (unless I play them side by side, who does that !). Only downside is I lose the ability to bitstream DTS straight into my amp as I now have to re-encode and I am not paying for a DTS encoder.

Was that a moth that just flew out of my wallet !!

Why 120Hz and 240Hz, would 96Hz not be sufficient or are you meaning that nobody would make a 96Hz TV they would only make 120Hz or 240Hz. Would the panel truly have a refresh rate of 120Hz ?

[ramicio]

Because 96Hz would not display anything but film. 120Hz is plenty, would take care of film (120/24=5, an integer) and NTSC (120/60=2, an integer). The general public uses their TVs more for TV than for cinema. Most of TV is 24Hz now, anyway. I always said if I got rich I would go to a company to have a TV designed around a plasma panel, since they have a 600 Hz sub-field drive, all a person would need is hacked electronics to enable displaying any film, NTSC, or PAL, without judder. I think the best solution would be for the film idiots to just move up to 60Hz. Even 30Hz would be a huge improvement.

[madhatter300871]

120Hz is plenty, would take care of film (120/24=5, an integer) and NTSC (120/60=2, an integer).

Off course the UK would suffer then as we have 50Hz TVs. (or 100Hz) Don't we ??

Anyway, I think my only real solution here (for me at least) is to 'convert' to 25 frames per second. Would you agree ?

I am talking only about my projector here which doesn't support 24p (even if that support is nothing but hype and technical misdirection). My TV does purport to support 24p, wether it does or not is another matter and wether 24p really means 23.976 is yet again another matter.

My TV supports PAL (50/60) NTSC(60) RGB(50) RGB(60) via scart. It supports 720p(50/60), 1080i(50/60), 1080p(24/50/60) via hdmi.

What on earth is PAL 60 ? God this just gets worse .... lol

[Ghitulescu]

Any European TV can play "NTSC" (as the general term, including blu-rays) sources. Why converting them?

[ramicio]

Any European TV can play "NTSC" (as the general term, including blu-rays) sources. Why converting them?

But they are still 100Hz and 200Hz. They can watch anything from their native land without judder, but anything good to watch will be NTSC and will be juddery.

[ramicio]

My TV does purport to support 24p, wether it does or not is another matter and wether 24p really means 23.976 is yet again another matter.

It does mean 24/1.001. There is nothing shot in literal 24 FPS anymore. Only an idiot would do that these days (blender movies).

[Ghitulescu]

But they are still 100Hz and 200Hz. They can watch anything from their native land without judder, but anything good to watch will be NTSC and will be juddery.

My Pioneer has 3 driving frequencies, so it fits PAL/NTSC/Film. :)

[hello_hello]

It does mean 24/1.001. There is nothing shot in literal 24 FPS anymore.

Really?? Got anything to support that contention?

[Ghitulescu]

What on earth is PAL 60 ? God this just gets worse .... lol

There is a PAL60 thing, it's about how a PAL player plays a NTSC video on a PAL TV.

[ramicio]

Freedom of speech.

[hello_hello]

So nothing really?

[madhatter300871]

Hi...erm, not been on for a few days.

Have I missed something here ? I'm presuming Ramicio said something even more offensive and so the moderators have removed the whole argument.

Anyway ......

I've been doing more tests and trying to educate myself more and I am fairly confident I have it now. So to re-iterate, I believe the following :-

1. 23.976, 24, 25, 29.97 are all real world frame rates that are used in television, film and video.

2. The movie frame rate must be an exact multiple of the display refresh rate for smooth, judder free playback.

That's it really, that's what I have proved to myself.

There are many ways to match refresh rate to frame rate. Change the playback speed, apply telecine or apply some clever interpolation. For me, because I have a native 50Hz display, I choose to re-encode to 25fps adjusting the audio accordingly, the results are superb. I miss out on DTS audio, but I do own the original bluray so will have it waiting for when I change my display (no time soon).

[sneaker_ger]

There are many ways to match refresh rate to frame rate. Change the playback speed, apply telecine or apply some clever interpolation. For me, because I have a native 50Hz display, I choose to re-encode to 25fps adjusting the audio accordingly, the results are superb. I miss out on DTS audio, but I do own the original bluray so will have it waiting for when I change my display (no time soon).

Are you using a DirectShow player on your HTPC? Then you might want to take a look at ReClock (http://forum.slysoft.com/showthread.php?t=48271). It allows you to change the playback speed of your files while playing (even with preserving the pitch, if you wish for it). That way you could already now save your Blu-Ray rips with their original 24(/1001)Hz and intact DTS audio, and use ReClock to speed up while playing, until you buy a newer projector that supports judder free 24Hz playback.

[madhatter300871]

I am using MPC-HC with (usually) ffdshow. I have played with reclock and to change the audio rate it re encodes to AC3 anyway, so I thought I may as well do that offline. If I bitstream the DTS audio, I cant resample it. Can I ? Also, although it speeds up the video to 25fps again I thought may as well do this offline for what its worth.

[sneaker_ger]

I am using MPC-HC with (usually) ffdshow. I have played with reclock and to change the audio rate it re encodes to AC3 anyway, so I thought I may as well do that offline.

Can't you send uncompressed PCM?

If I bitstream the DTS audio, I cant resample it. Can I ?

Correct, you cannot bitstream this way anymore. But it would save you the trouble of redoing all your backups once you buy your new projector.

[Ghitulescu]

Is your projector giving you "troubles" also when connected to a real blu-ray player? If you don't have one, can you borrow one (from a friend, relative etc., there are even shops that do this)? This will trace the problem to HTPC or to projector.

PS: what is the exact model of your projector?

[madhatter300871]

I can send uncompressed PCM, but this defeats the object of having the amp decode the DTS. I bought the amp therefore I want it working hard lol ....

Also, if I send it uncompressed PCM will it be resampled to the correct frequency to match 25fps ? Can you send an amp uncompressed PCM at any frequnecy or do they only accept 44.1 and 48 etc.

My projector is a Sanyo Z4, I'm not in a hurry to replace it, even though its old and only does 720p, because to be truthful I find it to be fantastic.

I havn't connected a standalone player to my PJ, I did consider it and thought why bother. But your correct, I should try this out shouldn't I. I can borrow one from work, It's a Samsung unit, about 6 months old, I'll give it a go. What i will say, though, is that I played a movie on it in work onto a 1080p monitor (not a TV) and I could see the motion judder about once every second, very noticeable on the Universal Globe ! Don't know what I deduce from this, just remember seeing it.

Right .... going to send my amp uncompressed PCM right now .... back in half an hour :)

[madhatter300871]

OK. Used reclock to speed the video up to 25fps with the audio output set to directsound.

Set ffdshow to passthrough the DTS audio, it plays but with jumps in the audio about every second or so. Makes sense.

Then I had ffdshow decode the audio and output PCM. No jumps in the audio and everything is in synch, but volume was very low, particularly in the centre channel and the LFE.

Tried AC3 filter also, same thing, lower level audio.

I then had ffsdhow encode to AC3 on the fly, volume levels fully restored, pounding base again.

Hmmm, you know keeps bringing me back to the idea of just encoding to 25fps with AC3 offline.

[sneaker_ger]

Hmmm, you know keeps bringing me back to the idea of just encoding to 25fps with AC3 offline.

With what benefit?

[Ghitulescu]

Then I had ffdshow decode the audio and output PCM. No jumps in the audio and everything is in synch, but volume was very low, particularly in the centre channel and the LFE.

Compared to what?

[madhatter300871]

Compared to what?

Compared to the original rip. I play the original rip, at 23.976fps, DTS passthrough to my amp. Audio sounds great. (Video judders off course).

I play the original rip, use reclock to change to 25fps and output audio via directsound, ffdshow to decode and output PCM to the amp. Audio is very low volume, very low base infact speech sounds dim and (hard to explain) like it is echoing slightly.

With what benefit?

Well, I am re-encoding the backup anyway to x264 so may as well re-encode the audio while I am at. Its trivial enough. And it means I can play it back by simply pressing play, not having to play with reclock or ffdshow. I have the time to spare to perform the offline encode, I have it working while I sleep. I don't suppose the ear will notice much difference, if any. Then I can watch the movie on my laptop or at home. I travel a lot for work and take movies with me, I back everything up because I hate the idea of scratching or ruining my movie collection, I have invested a lot of money so far in films (I didn't mean to but damn, they soon add up !)

[hello_hello]

I havn't connected a standalone player to my PJ, I did consider it and thought why bother. But your correct, I should try this out shouldn't I. I can borrow one from work, It's a Samsung unit, about 6 months old, I'll give it a go. What i will say, though, is that I played a movie on it in work onto a 1080p monitor (not a TV) and I could see the motion judder about once every second, very noticeable on the Universal Globe ! Don't know what I deduce from this, just remember seeing it.

I did comparisons using my PC and a Bluray player as the playback device conected to my TV, and any judder etc remained them same.
I don't think there's a logical reason why it shouldn't.....

Mind you I must admit, given that if I was to match the refresh rate to a multiple of the frame rate the judder would disappear but the motion would still be jittery, I've given up thinking about it too much. It's not something I really notice all that often, even if I'm looking for it.

For me the only perfect solution seems to be to increase the frame rate to match the refresh rate (50 or 60 Hz). I'm still intending to see if I can get this script to work in real time (currently I've only got it working for standard definition video). If not, I'm toying with the idea of using it for encoding as it does a really good job. http://www.spirton.com/convert-videos-to-60fps/

[Ghitulescu]

Compared to the original rip. I play the original rip, at 23.976fps, DTS passthrough to my amp. Audio sounds great. (Video judders off course).

I play the original rip, use reclock to change to 25fps and output audio via directsound, ffdshow to decode and output PCM to the amp. Audio is very low volume, very low base infact speech sounds dim and (hard to explain) like it is echoing slightly.

AFAIK the directshow audio passes through the kmixer (and this includes all the "enhancements" a sound card may offer). Check the settings there.

[madhatter300871]

Mind you I must admit, given that if I was to match the refresh rate to a multiple of the frame rate the judder would disappear but the motion would still be jittery

How come your motion was jittery but not with no judder ?

I played with Avisynth InterFrame plugin and, to be honest, I always could see strange effects in some frames, like a ghosting, presumably when it was interpolating frames. If I do continue to re-encode to 25fps I'm just going to perform a speedup.

AFAIK the directshow audio passes through the kmixer (and this includes all the "enhancements" a sound card may offer). Check the settings there.

Ahh, I'll check my mixer. I think kmixer is for linux no ? I'll check my windows audio mixer. Never thought of that !

I'm keen, though, to continue checking out my audio chain as perhaps I was a bit too quick to dismiss reclock. If I can get my PCM audio to sound right, well I think I've cracked it.