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.

[sneaker_ger]

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.

It's not like you'd have to setup ReClock more than once. I suppose your laptop display doesn't use a multiple of 25 Hz, so it would be juddery as well. I just don't see the point in investing more time (reencoding every audio track in comparison to setting up ReClock once), when sometime in the future you might get a working 24 Hz setup. What are you gonna do then? Redo all your backups or setup ReClock to slowdown, degrading the sound quality even further (speedup->encode->slowdown) and having to do what you originally wanted to avoid?
But I guess I've made my point and will just be repeating myself from now on. Either way, it's your choice - do whatever you're fine with. I just wanted to show you a different route, that I think makes more sense.

[hello_hello]

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

Well I guess if you described "judder" as the effect of NTSC "3:2 pulldown" (24fps @ 60Hz etc) then the effect of 25fps @ 50Hz would be something you could describe as "jitter", I guess. Motion doesn't have the same "judder", but it's still not completely fluent.

[Ghitulescu]

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

The very first page in google after searching for kmixer:

KMixer is the Kernel Audio Mixer driver, a part of WDM Audio in various versions of Microsoft Windows which handles the mixing of....

[madhatter300871]

Ghitulescu ... yes, I should have googled it ! I work with Linux based VTS surveillance systems and use the KDE environment, Kmixer is the name of the audio mixer. Sometimes everything moulds into one and confusion sets in in my brain ! .... Thanks for the link.

Sneaker_ger ... I am thankfull for your points on Reclock, in fact I am coming round to your way of thinking. Just need to sort out my audio chain and see if the mixer is whats screwing up my levels.

Hello_Hello .... I play my 25fps material on a 50Hz display and it's very fluid indeed. I've never seen any "jitter" but I'll be looking out for it now ;)

[AnonCrow]

for 20 years or more all the monitors are multisynch
I find that over the past 20 years, true[1] multisync monitors[2] have gotten more and more rare.


[1] continuous scan range from 15,xxx Khz upto ~40/65/83KHz,
instead of fixed 15.xxx (and 24Khz), then 31.5Khz and up.

[2] Such TVs and especially projectors have become more common

[hello_hello]

Hello_Hello .... I play my 25fps material on a 50Hz display and it's very fluid indeed. I've never seen any "jitter" but I'll be looking out for it now ;)

Maybe the type of display being used makes a difference?
Using my Plasma I don't see judder (or jitter) all that often, but if the motion's at just the right speed across the screen then when I do see it, it's either one or the other (depending on the frame rate).
At one stage I took a "juddery" section of 23.976fps video and remuxed it at 25fps just to see how different it'd look. It still appeared to move in "steps" rather than being completely fluid, but without the judder.

[madhatter300871]

Yes, maybe it does. I've never owned a Plasma, my PJ and TV are both LCD. So far, with the PJ which is what I use for for movies, I have had no jitter or judder playing back content at 25fps.

Instead of remuxing it to 25fps, have you also tried using reclock to speed it up to 25fps at playback ? I have been guided towards reclock from this forum and , while I am still checking out some audio issues, I must say that the speedup to 25fps seems flawless.

[hello_hello]

I can't use reclock to speed everything up to 25fps yet as I can only connect the PC to the TV at 60Hz (even though I'm in PAL land).
Currently though I'm using the VGA connector. I haven't tried HDMI yet. It's possible the TV only supports 60Hz from a PC. The manual isn't exactly overly informative. Actually thinking about it, I'm not sure if I have the slightest clue whether my video card supports 50Hz using a VGA/DVI connector. Maybe I need to look into that.....
At the moment I use reclock to play everything at 24fps at it's the closest match to my 60Hz refresh rate, so I'm mostly reclocking in the opposite direction to you.

When I get a chance I'll upload a little section of video for you to try. It's actually just credits rolling past but on my TV they either look juddery at 24fps or jittery at 25/30fps. The only way they look fluid to me is scrolling past at 50/60fps (depending on the refresh rate).

--When I said I tried remuxing 24fps video to 25fps earlier and it was "jittery" I was actually using the Bluray player to test that video as it'll connect to the TV at 50Hz. The PC won't, so to use it for the same tests I've got to change the frame rate from 24fps to 30fps (at 60Hz). Either way though, motion can still be "jittery" instead of "juddery".
That's kind of why I lost interest in worrying about the judder, when motion still doesn't always look "fluid" even without it. It's something I only see every now and then anyway. It's not like the entire video is a constant judder distraction. For me the only real "fix" to make everything perfectly fluid would be a 50/60fps frame rate.

[hello_hello]

madhatter300871,
Thinking about it, does the original sample (http://www.spirton.com/uploads/InterFrame/20110618-Sample-Original.mkv) from this page (http://www.spirton.com/convert-videos-to-60fps/) look smooth/fluent to you if you convert it to 25fps? The first few seconds where the camera is panning still doesn't look smooth/fluent to me even at 30fps and 60Hz. There's no judder so it definitely looks better than it does at 24fps, but it's still a little "jittery".
At 60fps the camera panning is perfectly fluid, although 60fps is naturally too much of a speed increase.

[madhatter300871]

Hello_Hello

I'm away from home for a few weeks but I do want to continue this when I get back. I have downloaded the clip and played it on my laptop (I know its beating the object of this) and I do think I know what you mean during that panning scene.

I'll speed it up to 25fps when I get home and have another look and then I'll post you an answer.

[madhatter300871]

Back home from a business trip and have had a fresh look at this. I have now successfully used reclock to speed up my video to 25fps and resample the audio accordingly. There is off course a small increase in pitch but it has no impact on listening/viewing pleasure.

The volume problem I was having was indeed a mixer problem, , as Ghitulescu pointed out. My mixer had to be set to enable 'Dolby Live mode', not very intuitive but this enabled Dolby audio to be connected to my external amp via the optical spdif and all 5.1 channels burst back into life.

So I won't be re-encoding everything at 25fps and resampling the audio accordingly, reclock works a treat now I have figured out how to use it properly !

Hello_Hello : I downloaded the sample you linked to but could not speed it up to 25fps with reclock because it is video only - it doesn't have an audio stream. When played back as-is it judders if my projector is in either 50hz or 60hz mode, 50hz is worst. I then used avisynth to speed it up to 25fps and with my projector set at 50hz it played smooth, no judder what-so-ever. I think you might have better results if you connect your PC to your TV via HDMI, it may well be the case that you then don't need reclock at all as the TV will support 24p, if not then you could use reclock to play at 25fps with the TV at 50Hz ?

All of my troubles have been caused by the movie frame rate not being a multiple of the screen refresh rate. My projector is old, doesn't support 24p and there is no way I am replacing it yet, took me ages building my bespoke screen so reclock it is :)

[Ghitulescu]

To support both 24 and 24/1.001 you may use the VGA input and set the screen resolutions accordingly, ie 1024x768 and 800x600, respectively.
For DVDs and HD-DVDs you may activate the "Film" mode, which IVTC the regular 3:2 and 2:2 modes.
You may buy another projector, or, for the same amount of money, buy a "video optimiser" like DVDO Edge Green which has the possibility to adapt 24p to 50/60i (HDMI to HDMI).

[hello_hello]

Hello_Hello : I downloaded the sample you linked to but could not speed it up to 25fps with reclock because it is video only - it doesn't have an audio stream. When played back as-is it judders if my projector is in either 50hz or 60hz mode, 50hz is worst. I then used avisynth to speed it up to 25fps and with my projector set at 50hz it played smooth, no judder what-so-ever.

Sorry I forgot reclock wouldn't speed it up. I remuxed it at different frame rates while I was testing.
Yeah the judder disappears when the refresh rate is an exact multiple of the frame rate but on my TV at least the panning is still not smooth. The motion still appears to happen in "even steps", but without juddering. Experimenting with my CRT monitor gave me the same results.
Maybe due to the way it displays the video a projector tends to smooth stuff out more than a TV?
Ultimately I'd like to be able to use an AVISynth script to simply convert everything to 50 or 60 fps in real time (on playback). It looks really good on my TV but so far I've only been able to get it to work in real time for standard definition video. I didn't really spend a lot of time on it when I initially tried the script but I will sometime in the future. If using the mutlithreaded version of AVISynth can take all the workload off a single core it should work fine.

I think you might have better results if you connect your PC to your TV via HDMI, it may well be the case that you then don't need reclock at all as the TV will support 24p, if not then you could use reclock to play at 25fps with the TV at 50Hz ?

Yeah, reclock speeding everything up to 25fps is my current plan, I'll just have to get motivated to buy a DVI/HDMI adaptor sometime soon.
It's weird though that the judder which bothers you a fair bit doesn't really worry me that much (it's not like I see it all the time) while the jitter I see when the judder's gone is almost as bad as the judder was to me, while to you it looks smooth.
Different types of display? Different way we perceive things? Who knows....

[madhatter300871]

Hello_Hello : My projector isn't smoothing anything out, in fact I have turned off all of the "enhancments" anyway. Even so, they where only black stretch, noise reduction, that kind of thing.

I see NTSC judder all of the time, I can't miss it, but your right ... it's funny what annoys some people doesn't annoy others.

When I say "judder" I mean that every second there is a very definite stutter in slow moving panning scenes. This is a known and well documented phenomenon due to 23.976 not being a multiple of 25. I am still not exactly sure what you mean by "jitter" so I don't really know if I am seeing it in the downloaded sample, could you try to explain exactly what is is ?

Ghitulescu : Not buying a projector just yet .... the finance committee has blocked this motion for the time being :( Of all the things I've tried I now use reclock with good results.

[Ghitulescu]

Ghitulescu : Not buying a projector just yet .... the finance committee has blocked this motion for the time being :( Of all the things I've tried I now use reclock with good results.
But have you tried the other three solutions? :)

[hello_hello]

When I say "judder" I mean that every second there is a very definite stutter in slow moving panning scenes. This is a known and well documented phenomenon due to 23.976 not being a multiple of 25. I am still not exactly sure what you mean by "jitter" so I don't really know if I am seeing it in the downloaded sample, could you try to explain exactly what is is ?

Maybe jitter is the wrong word but I guess I use it to describe a lack of fluid motion. Maybe stutter would be another word to use.
In the video in question I can only see it at the start when the camera is panning, but even at 30fps/60hz the motion of the camera pan doesn't look fluid on my TV. It's like the camera pan happens in quick, but distinguishable "steps". Unlike judder though they're even steps.

That's why some newer TVs have a function to add "interpolated" frames to make motion more fluid. It may not be something you can see using a projector. If you can't I'm not sure why as I don't know much about projectors.

[Richard1485]

In the video in question I can only see it at the start when the camera is panning, but even at 30fps/60hz the motion of the camera pan doesn't look fluid on my TV. It's like the camera pan happens in quick, but distinguishable "steps". Unlike judder though they're even steps.

I know exactly what you're describing. Even when my Blu-ray player is outputting "1080p24" to my 24fps capable set, I often see this kind of motion during camera pans. At first I thought that it was because film is inherently jerky, even with a 3:3 or 5:5 pulldown applied, but recently I've been wondering if part of it is how televisions process 23.976fps HD signals.

[hello_hello]

I think film is inherently jerky. A Higher frame rate probably wouldn't hurt. I mentioned earlier in the thread, when I was experimenting with frame rates a while back, the only frame rate which gave me perfectly fluid motion was 60fps (at 60hz).

Is the same effect during motion something you can see when watching a movie at the cinema? I wouldn't know. I've probably been to the cinema twice in the last five or six years.

[Richard1485]

Is the same effect during motion something you can see when watching a movie at the cinema? I wouldn't know. I've probably been to the cinema twice in the last five or six years.

That's about as often as I go too, but I've made a mental note to check next time. I certainly don't recall the effect, so I wonder if US 120Hz sets experience it, or if it's related to how European TVs handle 23.976fps content.

[hello_hello]

I'd be surprised if it's unique to European TVs. Maybe because I just wasn't looking for it, or maybe because the screen size is smaller, I'd not noticed it in the past when playing video on my CRT monitor. I can see it now though.

[sneaker_ger]

Since the advent of HDTV European sets don't really differ from the US TVs with the exception of universal support for 50 Hz input. When playing 24p Blu-Rays Europeans for the first time got the same judder the US viewers were already used to, i.e. 24 Hz played at 60 Hz. Maybe 24p mode got a bit more marketing in Europe because it was a new problem there, but that's about it.

[Richard1485]

When playing 24p Blu-Rays Europeans for the first time got the same judder the US viewers were already used to

I believe I had already experienced that judder when playing NTSC imports, unless European equipment does something different from a 2:3 pulldown when playing back NTSC.

I'm still interested to know exactly how playback of 23.976fps material and playback of true 24p material differ. There must be some explanation for the effect during motion that hello_hello described.

[hello_hello]

I'm still interested to know exactly how playback of 23.976fps material and playback of true 24p material differ. There must be some explanation for the effect during motion that hello_hello described.

I think it's just a matter of whether the TV supports 24p. ie if it can use a refresh rate which is an even multiple of the frame rate. I think 120hz is fairly common but I've been doing a little more research and it seems 24hz is also used. I guess it was the 24p refresh rate used before manufacturers started bumping it up so they could claim it was better when marketing TVs. I think 23.976 can still be played in 24p mode (I assume the player just plays it as 24fps) otherwise it's 60hz with judder. From what I understand at the moment a PC needs Vista or higher to be able to use a refresh rate of 24hz (I'm still on XP) but I'll have to do some more googling/reading.

Thanks to this thread (http://forum.doom9.org/showthread.php?p=1547864#post1547864) I discovered when using the PC I can use different refresh rates with my TV if I'm willing to sacrifice a little resolution (which is no big deal as 99.9% of the video I play is 720p), which will allow me to use a 70hz or 72hz refresh rate to fix the judder (my TV doesn't support 24p). I haven't had time to experiment with it much yet but while I doubt it'll effect the "jitter" hopefully it'll get rid of the judder.
Eventually I might stick Win7 on this PC just to see what refresh rates I can use and how much difference it makes. I've got the PC connected via VGA at the moment so I'll have to try to pick up a DVI adapter soon to see if the refresh rates the TV supports using HDMI are any different. Unfortunately the manual tells me nothing.

[Richard1485]

I think it's just a matter of whether the TV supports 24p. ie if it can use a refresh rate which is an even multiple of the frame rate.

That's just it though. 24 is an even multiple of 120, but 23.976 isn't, so there must be some difference in how those frame rates are handled, even if it's simply that 199.88Hz is also supported.

I think 120hz is fairly common but I've been doing a little more research and it seems 24hz is also used.

Surely film material can't be displayed at 24Hz though because the judder would be awful. The TV has to apply a 5:5 pulldown or some such.

[sneaker_ger]

I believe I had already experienced that judder when playing NTSC imports, unless European equipment does something different from a 2:3 pulldown when playing back NTSC.

I should have written "average European viewer". The average person does not import NTSC titles.

[smok3]

the film fps is certainly bothering some people in the industry as well, like Peter Jackson with his gnome saga:
http://www.aintitcool.com/node/49234

slightly offtopic:
as for the LCD & plasma stuff, this days i'am playing with kona3g connected with some JVC LCD display and its pure pain so far, to look at SD resolution for example, it does switch from 50i to 60i easily thought, but thats really not an issue if all the material is 25p or 50i..., not to mention the wonderfull drivers that aja did with cooperation with adobe (crash after crash, loosing embeded SDI audio all the time, ect..., and thats on 12 core machine btw - and all that was supposed to be used for pros). Whats interesting is that it can for example play HD tga sequence with alpha in real-time on premiere timeline, but who cares really.

Basically an LCD can't be any reference for say PAL people still using crt displays, so my first job after new year will be to find a small crt display to put it onto 2nd aja output.

To conclude: I love crt't.

[hello_hello]

That's just it though. 24 is an even multiple of 120, but 23.976 isn't, so there must be some difference in how those frame rates are handled, even if it's simply that 199.88Hz is also supported.

I was looking at a TV manual (not one I own) while discussing this subject in another thread, and I'm pretty sure it's refresh rates in "film mode" were either 23.976hz or 24hz.
Chances are (although I don't know for sure) some players/TVs may simply speed 23.976 video up to 24fps to match a refresh rate such as 120hz. I doubt anyone would complain.

Surely film material can't be displayed at 24Hz though because the judder would be awful. The TV has to apply a 5:5 pulldown or some such.

Why? The whole cause of judder is the refresh rate not being an exact multiple of the frame rate. You can't get a closer frame/refresh rate match than them being exactly the same so there'd be no pulldown required.
I think higher refresh rates (72hz or 120hz) are used because it sells TVs (especially LCDs) and because having the same refresh rate and frame rate can cause "flicker". Plus higher refresh rates are supposed to increase an LC's response time. Not that I'm an expert on it but I think the flicker problem is a Plasma one, not an LCD one. I do recall reading somewhere that Plasma TVs which support 24p use higher refresh rates these days to fix the flicker problem.

[hello_hello]

I should have written "average European viewer". The average person does not import NTSC titles.

They don't seem to have to. Yesterday my sister hired a few DVDs (I'm in Australia) and one of them was NTSC. That's not an especially unusual occurrence. I don't know exactly why the local shop hires out NTSC DVDs at times (they're a big video chain). Maybe it's something to do with the availability of a PAL version.... I'm not sure.

[Richard1485]

That's not an especially unusual occurrence.

I've experienced the same thing, especially with rentals.

[hello_hello]

I guess it shows how universally playback of NTSC discs is supported by PAL players because the fact you're hiring an NTSC disc isn't something the video shop ever feels the need to point out, and most people hiring DVDs probably wouldn't even notice whether a disc is PAL or NTSC.

[madhatter300871]

The projector doesn't do anything inherently different from a TV, be it LCB or plasma. The only difference would be the supported refresh rates/resolutions and built-in enhancements (which I turn off anyway).

Motion judder (NTSC judder if you like) is without a doubt caused by the refresh rate not being a multiple of the movie frame rate. I overcome this completely by using a PC and speeding up to 25fps, the change in audio pitch isn't noticeable.

I use windows XP and I can set my Nvidia card to output at 24Hz no problem by defining a custom resolution. My projector, however, doesn't like it so I stick with 50Hz and 25fps playback. It's smooth and flawless.

I don't think I'll ever have a standalone player now, the PC is much more flexible and once set up correctly gives excellent performance. I also wont move to Vista or 7 until I am absolutely forced to, XP is performing excellently as a platform for media playback. OK, later operating systems offer supposedly better renderers etc but really, my whole movie experience is quite superb.

What model of TV do you have ? You might want to try connecting via the HDMI connection, maybe the VGA and HDMI handle refresh rates differently, I really don't know. It's a long shot but ....

[hello_hello]

The projector doesn't do anything inherently different from a TV, be it LCB or plasma. The only difference would be the supported refresh rates/resolutions and built-in enhancements (which I turn off anyway).

I'm not so sure, but I know nothing about projectors. However someone else in this thread (I think) said they can see the "jitter" I described, however maybe how much of it you can see is display related in some way I don't understand.
I'm pretty sure what I'm referring to is what's described here as 24p "strobe". It is something different to "judder".
Disadvantages of 24p (http://en.wikipedia.org/wiki/24p#Disadvantages_of_24p)
As I said I can only see it during camera pans or motion at particular speeds (like the beginning of that sample). At higher speeds it's at least far less noticeable, maybe because motion blur kicks in and the brain starts to piece the frames together differently. I'm not too sure. I guess in that respect it has similarities to judder which I can generally only see at certain speeds too. If motion is fairly slow or really quick the judder effect seems to disappear. I guess that's why originally I said for me if I eliminate the judder I'm still left with the jitter where the judder used to be. :)

I use windows XP and I can set my Nvidia card to output at 24Hz no problem by defining a custom resolution. My projector, however, doesn't like it so I stick with 50Hz and 25fps playback. It's smooth and flawless.

So far, it still looks like I can only choose between 60hz, 70hz, 72hz and 75hz. I actually managed to find a list of supported refresh rates for my TV (buried in the back of the manual I somehow missed it the first time). According to the manual, refresh rates either via VGA or HDMI are exactly the same (the TV has a PC dedicated, HDMI input) although I'm not sure I'll take that as gospel as it doesn't list some resolutions as being supported (1280x720 for example) which work fine.
Using the Nvidia control panel, now I've finally discovered how to customize resolutions properly, I can't customize any different combinations than I can get via Windows Display Properties. At least none which seem to work.

To get 72hz I'm going to have to drop the resolution but I'll have to play around to see if it makes a perceivable difference to the sharpness of video. Given it certainly does to text (at 1080p text is nice and sharp whereas at lower resolutions text has that horrible LCD "blurred" look).
I'm just not sure whether I'll be able to determine the effect of changing resolution on video all that accurately though. By the time I look at video, change the screen resolution and then look at it again.... well unless the difference is so great it leaps out at me the time it takes between resolution changes is way too long for a valid A/B test.

I don't think I'll ever have a standalone player now, the PC is much more flexible and once set up correctly gives excellent performance. I also wont move to Vista or 7 until I am absolutely forced to, XP is performing excellently as a platform for media playback. OK, later operating systems offer supposedly better renderers etc but really, my whole movie experience is quite superb.

I couldn't agree more. I've used the PC exclusively for quite a while but it wasn't until recently when I bought a Bluray player I could compare the two (I was only pausing the video on identical frames and switching TV inputs or doing the same with the video playing) but even so the difference in picture quality was significant enough to reveal the PC produces a better picture. It actually surprised me a little because to be honest I hadn't expected that.
When it comes to upscaling I don't even need to A/B them to see a difference. No matter what noise reduction settings I use (or not) on the TV there's no way I can duplicate the way video is upscaled using the PC. With the PC even a decent standard definition AVI looks quite good (at least at normal viewing distance). Using the Bluray player all the compression artifacts etc are way more pronounced.
Plus if I'm going to be able to eliminate the judder, the PC is my only hope.

What model of TV do you have ? You might want to try connecting via the HDMI connection, maybe the VGA and HDMI handle refresh rates differently, I really don't know. It's a long shot but ....

Samsung PS51D450 Plasma (edit: I posted the wrong model number originally. It's the 450, not the 550).
At least I know it's not the PC causing the "jitter" or "strobe" effect. I've already tried remuxing different sections of video at 25fps and 30fps and playing them on the Bluray player and the result is the same as when using the PC. I'll continue to experiment.....

[hello_hello]

Well that didn't take long.....
I found a resolution which worked happily at 72hz (1360x768) and ignored the oddness of the TV telling me it was displaying at 1024x768 because the aspect ratio of video still looked normal. A quick comparison of a fairly sharp 720p video didn't seem to produce a noticeable drop in clarity over using the native 1920x1080p resolution, and it did seem to fix the judder, only to me the 24p "strobe" effect where the judder used to be isn't all that less annoying so I just went back to 1080p.

Looks like a script to increase the frame rate to 60fps will be my last hope, but I'm going to have to leave experimenting with that until another day.

[madhatter300871]

I'm finding it hard to believe that you are going to have to use a script to generate 60fps video, something doesn't seem quite right here, I'm sure we must have missed something.

I had a look at the manual for your TV, have you tried playing a video using the "Allshare" application ? Is it any better (judder/jitter wise only).

The manual indicates that the correct frequency to be selected when connected to a PC is 60Hz, so I am thinking that when connected via HDMI you should be able to set 50Hz. I haven't read this in the manual, I am making a presumption. If so, you can use reclock to speed up to 25fps. This is what I do (and alot of other from what I have read here) and the results are great. I mean, we have been watching US movies sped up to 25fps for years haven't we. Can you connect via HDMI to check ?

[hello_hello]

No, I've never run the "Allshare" application.

I'm yet to buy a DVI to HDMI adapter so I can connect via HDMI. The manual seems to indicate the refresh rates for the dedicated PC/HDMI input and VGA are exactly the same, however the TV operates at 50hz when playing PAL video via the Bluray player so there's possibly a chance I could use a standard HDMI input with the PC and connect it at 50hz. If that works I probably will use ReClock and just watch everything at 25fps although I still think I'll simply be replacing the judder with 25p "strobe".

I did try connecting the PC at 50hz via VGA but even once I overcame my initial dumbness and worked out how to create custom video profiles properly, setting the refresh rate to 50hz wouldn't work. Every time I saved the custom setup it'd automatically change back to 60hz as I saved it. I'll buy a HDMI adaptor soon.

I actually don't mind using a script to generate 60fps video if I can get it to work and it does a good job of interpolating frames as it'll get rid of the 24p "strobe" effect. Mind you neither the strobe or judder really annoy me all that much, it's just that I don't find one to be particularly more annoying than the other. It's only something I see now and then, although if I can make the video look perfectly smooth then I guess, why not? I wonder if for some reason the 24p strobe effect is more pronounced using a Plasma than it is when using another type of display? There is an LCD in this house which supports 1080p/24 so later today I might remux some juddery sections of video into little test files at 24fps and 25fps to see how they display on that TV. Mind you even if they're perfectly smooth I don't think I could see myself giving up my Plasma for an LCD, but it'll be interesting to see if there's much difference.

[madhatter300871]

I doubt the VGA input will accept 50Hz, I know the HDMI will. Thinking about this more I think you might be experiencing the following :-

Judder, caused by playing 23.976 or 24 fps video at a non-multiple refresh rate, jitter being caused by 23.976/24 material being telecined to play at 60Hz. Does this sound feasible ?

You dont need to buy an adapter, go to cableuniverse.com (or similar) and just buy a DVI to HDMI cable, I have a 7m one, works a treat.

I am quietly confident switching to 50Hz and speeding up to 25fps will give you the best results.

[hello_hello]

Judder, caused by playing 23.976 or 24 fps video at a non-multiple refresh rate, jitter being caused by 23.976/24 material being telecined to play at 60Hz. Does this sound feasible ?

Not really to be honest. I can't tests for jitter at 24fps because I get judder at that frame rate. While testing for jitter I have to remux the video at either 25 or 30fps (depending on the refresh rate). Or use reclock to change the frame rate if I'm testing with the PC.

I am quietly confident switching to 50Hz and speeding up to 25fps will give you the best results.

Hopefully. I'll buy a DVI-HDMI lead this week.

I almost wish I'd bought the model which supports 24p (I posted the model number of the TV which does in my earlier post but I've edited the post to change it to the model number of the TV I actually own). Mind you I don't know if it works all that well or how it works because as far as I know the PS51D550 still refreshes at 60hz, although that could be wrong. I haven't checked. The 550 has a cinema smooth mode (or whatever they call it) which the 450 doesn't have.

[madhatter300871]

When film is telecined for NTSC frame rate there will off course be a frame made of alternating fields every second, could this be what your seeing ?

I'm going to have to hold my hands up and just admit I really don't know the difference between 'judder' and 'jitter'. For me at least, if I play back video at anything other than an even multiple of refresh rate I get what I believe to be termed 'judder', most noticeable on slow horizontal panning scenes. I have never experience 'jitter' and still don't really know what you mean.

Sorry for my ignorance, I know it's not been helpful. I'll be interested to know if you have smooth playback at 25fps when connected via HDMI.

[hello_hello]

No, the jitter or "24p strobe", is just something I can see when the refresh rate is multiple of the frame rate (25fps and 50hz etc in my case). I can see the difference more clearly when slowing the frame rate with ReClock. At 12fps (60hz), I can see judder a lot more frequently. Likewise at 15fps the judder disappears but the strobe effect is a lot more prominent.

My TV does have a film mode (not the same as cinema mode) but it's not available when using the VGA input. If it reduces the strobe effect (which I guess it's designed to do) I'll find out when I switch to HDMI. Thinking about it, later I'll try a few video samples using the Bluray player and enable it to see what the result is like. You never know, it might reduce how noticeable the judder is too. The manual says it's supposed to "smooth" video, but doesn't offer anything more descriptive.

[madhatter300871]

I'll stay tuned.

[madhatter300871]

Hello_Hello : how did you get on, did you try your HDMI connection ? Just curioyus :)

[hello_hello]

Nope. Not yet. I'm being slack I know......

I came very close to testing it out the TV's "film" mode using the Bluray player last night, but got involved in a discussion in another thread regarding some encoding problems and didn't get there. I'm curious to see if it's something which will help reduce the "jitter" effect (as opposed to the judder).

As soon as I've bought the DVI to HDMI cable, which I'm going to make an effort to do next week, I'll post back with the results.

[hello_hello]

Well I did discover one thing today. The Sony Bluray player is too retarded to switch to 50hz when playing 25fps video via USB. Works perfectly playing a disc. I haven't tested the Samsung player yet, but the Samsung TV does seem to switch to 50hz. I'm not 100% sure because unlike when I'm playing an external source the TV doesn't display the refresh rate when I press the info button, but at the moment if I remux a 24fps video at 25fps I'm fairly sure the motion is smoother. It's still jittery, but the judder seems to disappear. I'll have to test it with some different videos, but I guess I could always convert everything to 25fps then get the TV to play it via USB..... sigh.

Film mode also does nothing. I still can't find a definitive explanation of what it does but the description says one mode optimizes for video, the other for text in video (or something like that) and it's only available in 1080i mode anyway so I guess maybe it's a deinterlacing thing?

Looks like it will have to be the PC to the rescue again. I'll definitely pick up a DVI cable in the next few days.

[hello_hello]

I bought a DVI to HDMI lead today.... finally. Now if only the PC would boot while it's connected. There's always something......

[hello_hello]

Well I'm finally connected..... I'm only at the preliminary testing stage with some bugs to iron out, but the upshot of it all it I can now connect the PC at 50hz, use ReClock to play everything at 25fps, and I seem to have "PAL FILM mode". It still jitters or strobes though.... just without judder.

Something I don't quite understand..... when I connected the video card and went into it's properties I had some new refresh rates to play with.
24Hz interlaced, 25Hz interlaced, 30Hz interlaced and of course 50Hz and 60Hz. I'm just not sure I fully understand the interlaced reference yet..... well except for the fact the TV still seems to be refreshing at either 50Hz or 60Hz even when I use 24, 25 and 30. I assume the "interlaced" refresh rates expect interlaced video so the refresh rate is actually twice what the video card is saying it is (it's either 50 or 60Hz).

Which takes me back to the 24hz refresh rate. I'll confess when I saw it I allowed myself to get a little excited, but I'm fairly sure when running in 24hz, interlaced mode, the Screen is really refreshing at 60Hz. I'll have to look at some more video, but I'm fairly sure there's still judder when using the 24Hz refresh rate.

So..... aside from the fact I can't get MPC-HC's refresh rate changing function to work properly yet (it crashes whenever it tries changing to 25hz or 50hz), all is well. I guess I don't need to worry about using the refresh rate changing function anyway as I imagine I'll just leave the card running at 50Hz and use ReClock.

[Ghitulescu]

It appears that the more you read and learn here in this forum, the more you realise what a complicate thing is to set a PC to correctly play an original movie (ripped or not), the same way a standalone does. :) Good luck!

[hello_hello]

Well.... I'm sure you know the saying.... make something even an idiot can use and only an idiot will use it. ;)

But seriously? Over two weeks after the last post in this thread you suddenly need to throw in a "standalone players are better" post? Sigh.....

[Ghitulescu]

It appears that the more you read and learn here in this forum, the more you realise what a complicate thing is to set a PC to correctly play an original movie (ripped or not), the same way a standalone does. :)
Well.... I'm sure you know the saying.... make something even an idiot can use and only an idiot will use it. ;)

That is a good argument, indeed. A person preferring a standalone is an idiot. And people having two players are named how, ehm ehm?
My Sony BDP-S480 will happily read the entire contents of a 2TB NTFS, USB hard drive. It pleasantly surprised me when I first tried it. The Samsung Bluray player in this house will tooLast week I bought a Samsung BD-D5500 player and tested them both more thoroughly....Anyway, I exchanged the Samsung player for a Sony BDP-S480.

The point was actually that you argued for the sake of argument (read contradict), without any viable knowledge, just sophisms. It took you about 1 year to notice that could not synch perfectly to your monitor, that the black levels were false, and God knows what else is wrong, maybe something with HD audio. Meanwhile two standalones entered your house.

[hello_hello]

That is a good argument, indeed. A person preferring a standalone is an idiot. And people having two players are named how, ehm ehm?

Wow.... so while there's an opportunity for rational discussion awaiting you in the Cinavia thread, which it appears you'll ignore as you typically do when it's become obvious you're full of it, you're instead posting in old threads and hunting for out of context quotes in order to pick an argument. You really do need to grow up a bit.

Do you understand the distinction between "use" and "own", "preferring" and "having", or does even that simple concept need to be explained to you?


So, you're not happy with the PC playback of multimedia files, to resort to a standalone you criticised so strongly and factually not too long time ago? Is it something a standalone player might bring that a PC doesn't already have?

Yes, I'm perfectly happy with the PC as a media player. So happy, I've probably used the Bluray player in my room a handful of times, and then it was only while I was testing things. I'm yet to put a disc in it.

The point was actually that you argued for the sake of argument.... blah.... blah.... blah....

No, the point is you posted in a thread two weeks after the conversation ended because I've bruised your fragile man-child ego and you feel the need to try to score a point, but unfortunately you're only succeeding in making yourself look foolish.

I'll leave you to reply with whatever new waffle-fest you manage to come up with. You're not even amusing enough to retain my interest now.

[madhatter300871]

I wonder, do you think there might be a problem with the television ?

Using the DVI-HDMI cable, you now play smoothly at 50Hz, using reclock to speed up the video to 25fps (which is exactly what I do). My projector natively runs at 50Hz and i have to say playback is smooth and fluid, no judder (nor jitter).

Could you try your PC on a different TV (or projector)? You might not be able to, but I still think something is not quite right here.

[hello_hello]

Nah..... it's not the TV. At least I think what's happening is normal anyway, but I can't say I've done lots of comparing. The LCD TV in this house, which is fairly new, does have 24p mode and I've been meaning to to try some test files on it (it's not my TV) but haven't got there yet.
Now I know what I'm looking for I can see the same thing using the CRT monitor. I guess it never bothered me before because the screen is so much smaller.

Didée described the effect I've called "jitter" in this post. I'm pretty sure he's referring to the same thing. A "doubling" or "tripling" effect in some motion.
http://forum.doom9.org/showthread.php?p=1555695&highlight=triple#post1555695
That's why I've wondered if there's something in the way a projector works which doesn't produce the same effect.

[madhatter300871]

I read Didees post, I think I know what he is talking about. So if I am right in my understanding is what you are experiencing and call 'jitter' the effect that during motion scenes, particularly panning, you are seeing this frame duplication effect ? Almost as if the trailing edge of the moving image is leaving a trail (kind off). Believe it or not I think I have seen similar, the penny might be dropping for me now.

When I play a film via the DVD player the motion is noticeably less smooth than when I play it directly through the TV. (My LG flat screen can play movies directly from a USB pen drive). I wonder if what I am seeing is what you call 'jitter', I think it might be. For me, I just don't use the DVD player anymore, unless I absolutely have to.

[hello_hello]

The "jitter" or "edge duplication effect" only seems to be noticeable at certain speeds. At least to me. It also happens to be about the same range of motion (speed) where I can see judder if the video is 24fps and the refresh rate 60hz. If it's fairly slow it looks fluid. If it's fairly fast it also looks fluid. It's just that middle ground..... probably the speed where film produces the so called "strobe" effect. That's why ages ago I said to me it seems to be one or the other, although the "jitter" is definitely preferable to "judder".

I don't quite understand why the "edge duplication effect" (assuming that's the best way to describe it) actually happens. I can see the same thing on my CRT monitor now I look for it, so I thought maybe it was just the way PC video cards work, but a while back I used the Bluray player to look at some "problem" motion scenes and they look the same as when using the PC. Maybe it's got something to do with response time, although I'm using a Plasma so there should be no problem there. I understand why film can look "jerky" when motion is happening at a certain speed... well I assume it relates directly to the frame rate.... but why TVs produce that "doubling of edges" effect, I don't know. Hopefully someone will come along and explain it.

I watch a lot of documentaries on the universe which often have animation of objects moving through space with stars (basically white dots) also moving in the background. At slow speed the motion of the stars looks smooth, then as the speed picks up each star is duplicated or triplicated (is that a word?) until finally the speed picks up until the motion of stars becomes a blurred line. At first I thought that's just the way the computer graphics were done, until I started pausing the video during motion scenes and discovered the stars aren't duplicated in the actual video..... I can see the same thing using the CRT monitor too.

I'll have to "commandeer" the LCD TV in this house one afternoon to see if it produces the same effect and if it's 24p mode gets rid of it.

I'd assume when using the DVD player you're refreshing at 60hz so I'd assume the added "judder" robs the video of smoothness at certain speeds. I still wonder if projectors might produce the image differently enough to Plasmas or LCDs to make them look smoother? I don't know, I've not had any real experience using one. Film is projected by flashing each frame two or three times to remove "flicker" etc so chances are our brains perceive a projected film image differently to one displayed by a TV.... I don't know....

[madhatter300871]

If triplicated isn't a word then it should be ! :)

I don't think the LCD projector works differently to an LCD TV, there is still an LCD panel with an image on it, although it is feasible that LCD, CRT and Plasma work in different ways (well clearly they do because they are different technologies).

On a side note, can you explain to me your understanding of the 'film effect'.

I now have a clear understanding of jitter and judder and wonder if jitter is related to the film effect.

Just to re-iterate I don't see any jitter what so ever on my projector, but do suffer with judder when playing back 23.976fps content.

[hello_hello]

To me, jitter and the "film effect" are pretty much the same thing.... motion at certain speeds doesn't look "fluid". Well at least I assume they're the same thing.....

As I said, it's something I only see now and then, but here's a little sample (http://www.mediafire.com/?n9r7uakh51i7q1t).... which is why it took me a while to reply. I remembered the scene well as the judder stood out more than I think it ever has before (pre 50hz refresh rate, now it's jitter), but I only just got around to finding which episode it was in. This sample (already 25fps).... the camera pan doesn't look anything even close to being fluid to me even with a 50hz refresh rate. It's "jittery". Where the camera pans past the legs of the guard with the gun, the light coming from behind gives it a strobe effect and the edge duplication/triplication of the guard's dark uniform is fairly obvious. If I pause there and step through one frame at a time I can see the edge duplication isn't in the video itself. Each frame looks fine. At 50fps it looks good, but that's a little too much of a speed increase. :)

PS. If it looks fluid to you using your projector, what about using something else such as a PC monitor? Playing it on my CRT with it's 85hz refresh rate makes it look even less fluid.

[Didée]

Sample. And. Hold.

http://www.mediafire.com/?xrda455a7w1kkbb


(German) explanation: klick (http://www.hifi-forum.de/index.php?action=browseT&forum_id=133&thread=7149&postID=28#28)

[Didée]

A quick try in english -

When the eye is tracking a moving object, the eye is moving continuously. In contrast, the picture on a sample&hold display (most prominently LCD screens, but more generally also plasma screens, or projectors) is standing still for ~40ms, then switching the next picture, again standing still for ~40ms, etc.

First consequence is that the image on the eye's retina is getting blurred. It's the same principle as a static photo camera shooting a fast-moving object, just the other way round: a moving camera (eye) is shooting a static object (sample&hold image frame).

However, it's not the same as the "motion blur" that's catched by a film camera with long shutter. It is much worse than that. A film camera is sampling over continuous motion, hence the motion blur is "natural" and evenly distributed.

When watching a 24/25 fps film on a sampl&hold display, the eye is presented with fractional motion, and it does a dynamically "running window" sampling over that fractional motion. The resulting effect is that the motion blur building up on the retina in fact is creating "backwards motion" during the integration time of one frame, plus "double image'ing" when the transition from one frame to the next is happening.

Retina persistance is playing a big role in the process, which also explains why the effect is most prominent on high-contrast detail, and much less in dimmed scenes. (The bright parts sting much light energy onto the retina, forcing a much stronger persistance, compared to the low-energy of dimmed detail / dimmed scenery.)

[hello_hello]

I'm not sure I fully understand your explanation yet, but the "sample and hold" effect in your example is what I sometimes see, only I guess in your example it's somewhat exaggerated? I think I can see the same effect in the "real world motion" example when it's displayed on the Plasma, only it's very minimal.

[Didée]

That video is intended to be a slow-motion analysis of what's actually happening in your bio-camera. (And for that purpose, the 60fps version isn't important.)

A more brutal video for the "I-dont-want-my-TV-to-do-any-motionmagic" fraction is this lighthouse video (http://www.mediafire.com/?1eh4xvd1ir46jzi).
(Yessss, it is lacking motion blur. But when I made the same sequence *with* motionblur, the visual effect was almost the same.)

[hello_hello]

Some questions regarding your lighthouse video.....

On my plasma (50Hz) at 25fps it's "jittery" with obvious edge duplication/triplication, but why when I play it at 50fps is there still a "ghosting" effect? The motion is smooth at 50fps but there's still edge duplication or "blur".

I tried the same thing using my CRT monitor (85hz). When playing the video at 42.5fps it looks the same as the Plasma does when the frame rate and the refresh rate are an exact match (motion is smooth but there's "edge blur"). When I increase the frame rate to 85fps it's perfect on the CRT. No blurring or edge duplication, the pictures slide past looking exactly as they would when still.

In other words when using the plasma, and when the frame rate and refresh rate match, it looks the same as when using the CRT with the frame rate being half the refresh rate. So the plasma can't do what the CRT does, which is for motion to look perfect when the frame rate and refresh rate match. I'm just trying to understand the "why" when it comes to the difference between the displays.

My plasma doesn't do frame interpolation.

[Didée]

Well, many of the "hardcore" pasma fans are telling that it's only those darn LCD screens that have problems with smooth motion, and plasma and only plasma and nothing but plasma could do. The truth is that ... this is not true. Plasma displays are somewhat more forgiving with this problem, but not by that much. In essence they face the same technical problem as LCDs do. (I assume a bigger point is that most plasmas have a darker picture than LCD panels. And/or: many LCD screens are set too bright. More light energy => bigger problem due to stronger retina persistence. Darker picture => less problem because of less retina persistence.)


For the differences - it's a puzzle of many small pieces, you can't break it down that easily to one definite answer.

First, the (playback) framerate does make a difference. When you play the sequence at 25fps, then each picture is lasting for 40ms. At 50fps, each picture is lasting for only 20ms, and at 85fps, its only 11.7ms. Obviously you cannot (shouldnot) compare "the effect" directly to each other.

The strength of the CRT at its native refresh rate is that the CRT is *halfway* an impulse-type display. It isn't truly one because of the phosphor afterglow (and nobody would bear to watch a *true* impulse display), but still, each pixel is most bright in the moment it is activated by the cathode ray, and fades to dark(er) afterwards. When framerate is matching the refresh rate, then the "peristance" of the shown picture is dimished because of the brightness fade. The next time the ray comes along, it produces a new motion state. This is basically "impulse type" (and practically halfway impulse because of the afterglow).
However, when dropping framerate to half refresh rate, then much of this beneficial effect gets lost: a pixel is activated, fades out, the ray comes again and again activates the same pixel at the same old motion state. Tadaaa!, sample+hold -problem even on a CRT.

[hello_hello]

First, the (playback) framerate does make a difference. When you play the sequence at 25fps, then each picture is lasting for 40ms. At 50fps, each picture is lasting for only 20ms, and at 85fps, its only 11.7ms. Obviously you cannot (shouldnot) compare "the effect" directly to each other.

Yeah, you're right. Bad/lazy assumption on my part. I dropped the CRT refresh rate to 60hz (I couldn't stand it that low for a monitor but when watching video it's okay) and tried again, also comparing it to the plasma again.

The plasma at 25fps/50hz does look a little more jittery than when it's running at 30fps/60hz but either way it's still horrible.
The plasma at 50fps/50hz definitely has more edge duplication than it does at 60fps/60hz but it's still nowhere near as good as the CRT at 60fps/60hz.

The CRT at 30fps/60hz doesn't look much different to the plasma at 30fps/60hz.
The CRT at 60fps/60hz looks much better than the plasma at 60fps/60hz. There's no significant "ghosting" and no edge duplication. I can see a little blurring of the blue where it turns to black but I assume that's just the phosphor afterglow and nothing I'd notice when watching "normal" video.

So yeah, what you're saying makes sense.
I'll be keeping your video for future testing. While the PC and the plasma seemed happy to play together at 50hz.... not so much at 60hz. Even Reclock didn't help with the odd dropped/duplicated frame or the tearing when resizing video which I thought I'd fixed, but as it turns out the fix (telling the renderer to wait for flushes) was fixing the tearing but causing more dropped/duplicated frames. Playing with the vsync offset in MPC-HC basically got everything running smooth and fixed the tearing, so your video is definitely handy for revealing problems. Mind you these days I use Reclock to play everything in "PAL cinema" mode anyway (25fps/50hz). At least it eliminates the 60hz judder.

[hello_hello]

One other question.... I've basically assumed what you're calling the sample and hold effect is the same thing as film 24p "strobe" or jitter. Well not so much assuming they're the same thing, but assuming where the film 24p strobe/jitter effect would be noticeable is generally the same motion/speed where the sample and hold effect becomes obvious on a Plasma/LCD display.

Would it be fair to assume the film 24p strobe and Plasma/LCD sample and hold effect are noticeable around the same range of motion/speed and therefore related in that way, or does one not have much to do with the other?

[hello_hello]

It's a pity SED or FED displays never happened. They sound like they would have been a nice compromise between a CRT and a Plasma/LCD.

[ramicio]

It's not a sample and hold problem. It's a combination of larger display sizes of the present times, low FPS, and lack of motion blur.

[Didée]

display size - no
low fps - sure, that's why we are talking at all
lack of motion blur - basically no

Display size doesn't matter, resp. you must take into account the viewing distance. My monitor is 24", my TV is 40", but on the bigger TV the problem isn't worse than on the smaller monitor. (Because of viewing distance the picture of my monitor is "bigger". Intercept Theorem, you know.)

To check that scrolling scene with motion blur, I had provided the same scene WITH motion blur (http://forum.doom9.org/showthread.php?p=1550377#post1550377) (change framerate by yourself to whatever you want to test, Vdub does it in a breeze, it's just an AVI), and the problem is pretty much the same. Sure, it is less obvious, because local contrast of the moving bits is reduced. But the underlying problem has not changed in any way. (Like the bad sound of a crappish musicplayer - when you reduce the volume, then the sound is less annoying. But it doesn't get better because of that.)


The problem is not so much sample&hold in itself, but rather the interaction happening on the retina. To see the difference, watch the sample out-of-focus (not exactly easy to do). While it is running, focus on a point some meters behind the screen, or hold a finger before your nose and focus the finger. While keeping that focus, put attention to the scrolling scene. Only when the screen is out-of-focus, and eyes are NOT TRACKING the motion, only then it is possible to see the raw strobing motion of film rate, but without those retina-blur/sample sideeffects.

[ramicio]

Display size, yes. The average size of a CRT was like half of the average size a person buys of a panel, and they say far away. The close you are to a screen, because you can be, because of the resolution, the more distance frames travel, thus making the tracking problem worse. Lack of motion blur, yes. The problem presents itself between slow motion and fast motion. Usually medium speed scene pans. They could also be shooting movies lately to do away with motion blur to make processing of motion interpolation on TVs more realistic, to do away with artifacts. The problem goes away when you simply move back.

There is no strobing... Strobing would be a 50% duty cycle of 24 Hz light, for actual film. Then they went to strobing at 48 Hz. You know what a strobe light is? It's flashing, not jagged video.

[Didée]

Well yeah ... is it a greenish bluething, or rather a blueish greenthing? Sure is only this: as soon as you butt in, it is, in any case, the other thing. :rolleyes:

I congratulate you for being a native english speaker. Discuss with me in German, meet your Waterloo. :)


- edit -

(since it seems sports to argue for the sake of arguing)

Yes, strobing light is a change of light/darkness/light/darkness. But to go by the word, I did not speak of strobing light, but of strobing motion. Call it an artistic interpretation, but ... if there is some continuous natural motion, then a strobing light turns the continuous motion into a chain of "snapshots in time", which is pretty much the characteristics of a digital video stream.

[hello_hello]

There is no strobing... Strobing would be a 50% duty cycle of 24 Hz light, for actual film. Then they went to strobing at 48 Hz. You know what a strobe light is? It's flashing, not jagged video.

Disadvantages of 24p (http://en.wikipedia.org/wiki/24p#Disadvantages_of_24p)

"In general, 24 frames-per-second video has more trouble with fast motion than other, higher frame rates, sometimes showing a "strobe" or "choppy" motion, just like 24 frame/s film will if shot as if it's video, without careful panning, zooming, and slower camera motion. It is therefore not well-suited for programming requiring spontaneous action or "reality" camerawork.

It should also be noted that while the strobe of 24p is in many ways considered a disadvantage, it's also part of the "film look." 24 frame/s film strobes in exactly the same way."

That's basically what I was referring to when I referred to 24p strobing. You can of course call it whatever you want.

[hello_hello]

Display size doesn't matter, resp. you must take into account the viewing distance. My monitor is 24", my TV is 40", but on the bigger TV the problem isn't worse than on the smaller monitor. (Because of viewing distance the picture of my monitor is "bigger". Intercept Theorem, you know.)


I'd agree with that according to the limited testing I can do. I can get far enough away from my CRT monitor for the sample and hold effect to basically disappear. I can't get far enough away from the plasma though. The room isn't big enough.

To check that scrolling scene with motion blur, I had provided the same scene WITH motion blur (http://forum.doom9.org/showthread.php?p=1550377#post1550377) (change framerate by yourself to whatever you want to test, Vdub does it in a breeze, it's just an AVI), and the problem is pretty much the same.

Agreed. It doesn't really look any different to the version without motion blur, except for the fact it's blurry. It still "jitters".

The problem is not so much sample&hold in itself, but rather the interaction happening on the retina. To see the difference, watch the sample out-of-focus (not exactly easy to do). While it is running, focus on a point some meters behind the screen, or hold a finger before your nose and focus the finger. While keeping that focus, put attention to the scrolling scene. Only when the screen is out-of-focus, and eyes are NOT TRACKING the motion, only then it is possible to see the raw strobing motion of film rate, but without those retina-blur/sample sideeffects.

It turned out to be fairly easy to watch the sample out of focus, I just played it and thought of ramicio. ;)
But yes, I could duplicate exactly what you're describing.