23.976 vs 23.972 vs 24 FPS

[Kelinya]

Hi,

I'm currently using Media Player Classic with LAV splitters and madVR to play 23.976 FPS source material from bluray.

In order to avoid 3:2 pulldown, I have changed the monitor's refresh rate from the native 60 Hz to 23 Hz. However, unfortunately, it seems that this "23 Hz" is in fact, according to PowerStrip, 23.972 Hz and not the 23.976 Hz intended.

I'd like to avoid using ReClock to stretch this to 24 FPS to play on the 24 Hz monitor refresh rate and would prefer to play this with the original source FPS. And I presume that it will still have to make some kind of correction to play 23.976 FPS footage on 23.972 Hz, correct?

Is there any way to avoid this?

Thanks.

[El Heggunte]

Before being transfered to Blu-Ray or DVD-Video, movies are ACTUALLY recorded @ 24fps.

Therefore I don't understand why someone would prefer watching a film at 23fps instead of 24fps.

[Cornucopia]

Movies that you watch in the cinema are shown at 24Hz (or whole multiples thereof, not counting those few historical exceptions such as Todd-AO). Period. End of story.

Movies that you watch on a TV that has not been specially modified to work for cinema or for scientific/research purposes (or those very few modern ones that are more versatile) is shown at either 25Hz (or whole multiples thereof) for PAL-based systems, or at 29.97Hz (or whole multiples thereof) for NTSC-based.

The whole point of Telecined 23.976 is too allow use of film-originated material on NTSC-based video systems. This pulldown ratio mirrors the pulldown ratio that would be necessary to go from 30 to 29.97 (IOW, 1000 / 1001), which occurs as a result of the transition from NTSC Black&White to NTSC Color system. (Note that some electronic cinema titles are actually recorded AT 23.976, with the intention of the primary outlet being TV vs. cinema itself).

So, barring a very few advanced exceptions, people are NEVER watching film electronically (i.e.: on a TV) in it's original framerate, no matter what part of the globe.

If you absolutely have to avoid pulldown, the best way to do this with consumer equipment is to use an advanced, modern HDTV that supports 120Hz/119.88Hz because this is a whole # multiple of both 24 (5x) & 30 (4x). IOW, a 24fps signal gets frame-quintupled to ~120, which can be directly shown on those devices without further adjustment.

BTW, any monitor that refreshes at such low rate as was originally intended is going to be rediculously flickering and would probably be unwatchable. Flicker fusion rates vary, but I think it is commonly agreed that anything below ~45Hz will be noticeable, if not obvious.

Also, your reliance on the verity of Powerstrip may be faulty also.

I would say you are making a mountain out of a molehill, and should leave well enough alone. Keep your monitor at 59.94/60Hz and accept telecined material for what it is.

Scott

[jagabo]

The difference between 23.976 and 23.972 is about one frame out of every 6000. You'll get one dropped frame every ~4 minutes. You will never notice that.

[Kelinya]

Before being transfered to Blu-Ray or DVD-Video, movies are ACTUALLY recorded @ 24fps.

Therefore I don't understand why someone would prefer watching a film at 23fps instead of 24fps.

Movies that you watch in the cinema are shown at 24Hz (or whole multiples thereof, not counting those few historical exceptions such as Todd-AO). Period. End of story.

Movies that you watch on a TV that has not been specially modified to work for cinema or for scientific/research purposes (or those very few modern ones that are more versatile) is shown at either 25Hz (or whole multiples thereof) for PAL-based systems, or at 29.97Hz (or whole multiples thereof) for NTSC-based.

The whole point of Telecined 23.976 is too allow use of film-originated material on NTSC-based video systems. This pulldown ratio mirrors the pulldown ratio that would be necessary to go from 30 to 29.97 (IOW, 1000 / 1001), which occurs as a result of the transition from NTSC Black&White to NTSC Color system. (Note that some electronic cinema titles are actually recorded AT 23.976, with the intention of the primary outlet being TV vs. cinema itself).

So, barring a very few advanced exceptions, people are NEVER watching film electronically (i.e.: on a TV) in it's original framerate, no matter what part of the globe.

If you absolutely have to avoid pulldown, the best way to do this with consumer equipment is to use an advanced, modern HDTV that supports 120Hz/119.88Hz because this is a whole # multiple of both 24 (5x) & 30 (4x). IOW, a 24fps signal gets frame-quintupled to ~120, which can be directly shown on those devices without further adjustment.

Thank you for your help.

I knew that movies were actually shot at 24 FPS but I thought that the transfer to 23.976 was kind of a lossy process, where you'd lose some information and that is why I asked this. I thought that putting it back at 24 FPS (with ReClock) was like converting a JPEG (that was originally compressed as PNG), back to PNG (sorry for the analogy ). But, apparently, this is not the case and the movie is simply slowed down and can be watched at 24 FPS with no problem.

So, with the setup I have mentioned previously, I could actually use ReClock to sync it at 24 FPS, from a 23.976 source and using the 24 Hz refresh rate on my monitor, I'd basically have the perfect output (as in a movie theater), without any kind of pulldown or correction, am I right? (I'd gladly use 48 Hz, however 24 Hz is the only multiple of 24 my monitor supports).

BTW, any monitor that refreshes at such low rate as was originally intended is going to be rediculously flickering and would probably be unwatchable. Flicker fusion rates vary, but I think it is commonly agreed that anything below ~45Hz will be noticeable, if not obvious.

Also, your reliance on the verity of Powerstrip may be faulty also.

I agree, it's unbearable to use such refresh rates for a desktop, but in the movie you obviously don't notice that, due to the 24 FPS speed, and that was why I was thinking of using AutoFrequency. So, basically, I would use:

Media Player Classic, LAV Filters, madVR, ReClock, AutoFrequency.

I'm from Europe, however I buy most of my movies and series from Amazon (US) and they are at 23.976 FPS and 29.97 FPS respectively. So for 29.97, I could sync it at 30 FPS and, in this case, watch it at 60 Hz refresh rate, right? And for the few PAL titles I have, just watch them at 50 Hz.

Also, buying a new monitor is out of the question for now, since I just bought one, but unfortunately it is only capable of 60 Hz max.

I would say you are making a mountain out of a molehill, and should leave well enough alone. Keep your monitor at 59.94/60Hz and accept telecined material for what it is.

Ha, you're right, I probably am. Sorry for this kind of questions, but I just decided to start a movie collection about 2 months ago and all of this was a sudden interest. I've been researching and VideoHelp has been a tremendous help. A couple of months ago I didn't even know that movies were recorded at different speeds. And since I've mild OCD, this is just unavoidable to me.

The difference between 23.976 and 23.972 is about one frame out of every 6000. You'll get one dropped frame every ~4 minutes. You will never notice that.

Thank you very much jagabo, that was exactly what I was looking for in the first place.

[hello_hello]

I'm from Europe, however I buy most of my movies and series from Amazon (US) and they are at 23.976 FPS and 29.97 FPS respectively. So for 29.97, I could sync it at 30 FPS and, in this case, watch it at 60 Hz refresh rate, right? And for the few PAL titles I have, just watch them at 50 Hz..

MPC-HC has an option to change the refresh rate/resolution of the monitor according to the frame rate when running full screen, although I just leave the refresh rate constant and use Reclock to adjust the frame rate.

Generally I watch everything as "PAL", courtesy of Reclock. I just leave the refresh rate at 50Hz and let Reclock speed 24fps video up to 25fps. That's pretty much the way we've been watching 24fps movies in PAL-Land for years (it's just sped up) so it's nothing new. You'd have to watch the sped up version along side the 24fps version to notice the difference. Reclock will resample the audio so the pitch doesn't increase if you want it to.
Of course it doesn't work for 29.970 "video" but I rarely watch much of that.

The main reason I don't use MadVR is because I could never get it to play nice with Reclock when using two monitors. I generally open a video by double clicking on it, so it opens on the PC monitor, and when I move MPC-HC to the TV, Reclock adjusts the frame rate accordingly..... except in combination with MadVR.... after moving the video to the TV, Reclock seems oblivious to the fact the refresh rate has changed for some reason.

I've used 24Hz and 25Hz refresh rates while watching video. LCD displays might be different but it looks perfectly fine using my Plasma (no flickering). Windows itself isn't as "fluid" though, so I stick with 50Hz.

[Cornucopia]

In general, I would agree with hello_hello about his PAL-related procedure.

It is important to note, however, that "FRAMERATE" and "REFRESHRATE" are NOT the same thing. Framerate is the timebase that your media plays at. Refreshrate is how fast images are displayed/projected given the particular device. And they don't necessarily have a 1:1 relationship.

For example, it has been the LONGSTANDING, UNIVERSAL practice to "double-flash" (or occasionally "triple-flash") film when projecting in the cinema. So while the film "runs by" at 24FPS, each frame is shown twice, with a minor gap of black in between, at a rate of 48 Hz (or "fps"). Doing without this technique results in a VERY NOTICEABLE stuttering. Why? Because of the fact that your eyes can "see" the frames change at the slow rate of 24, but NOT at the higher rate of 48 (and triple-flashing would give you 72fps).*

So, your idea of setting the monitor to 24Hz refresh is a very bad one (though actually I doubt it is actually truly letting you do that). If you live in a PAL-system area, monitors you buy should have the capability to use 50Hz (and/or whole multiples). And for you, that's what I'd set it to 50 or 100Hz refresh. Then reclock (aka SPEED UP) your 23.976 or 24 fps movies to 25 fps. If it is 29.97 from Telecined 23.976, I'd IVTC it back to 23.976 and then reclock to 25 (that's usually what the pros do with it).

Scott

*Note that there is some difference between the way CRTs, Plasmas & LCDs operate that changes the fluidity perception with refresh rates, but they all have "equivalents".

[Kelinya]

MPC-HC has an option to change the refresh rate/resolution of the monitor according to the frame rate when running full screen, although I just leave the refresh rate constant and use Reclock to adjust the frame rate.

Generally I watch everything as "PAL", courtesy of Reclock. I just leave the refresh rate at 50Hz and let Reclock speed 24fps video up to 25fps. That's pretty much the way we've been watching 24fps movies in PAL-Land for years (it's just sped up) so it's nothing new. You'd have to watch the sped up version along side the 24fps version to notice the difference. Reclock will resample the audio so the pitch doesn't increase if you want it to.
Of course it doesn't work for 29.970 "video" but I rarely watch much of that.

Thanks for the tip about MPC-HC, one thing less to install (Auto Frequency). And just found out that madVR is able to do that as well.

Well, I agree, that's a lot easier to do, however, my goal is to watch the videos how they were intended to be watched in the first place. So watching 23.976 FPS sped up to 24 FPS at a 24 Hz frequency (or 48, 72 etc...) seems to me like the perfect solution.

The main reason I don't use MadVR is because I could never get it to play nice with Reclock when using two monitors. I generally open a video by double clicking on it, so it opens on the PC monitor, and when I move MPC-HC to the TV, Reclock adjusts the frame rate accordingly..... except in combination with MadVR.... after moving the video to the TV, Reclock seems oblivious to the fact the refresh rate has changed for some reason.

Have you tried to choose your TV as the preferred screen on ReClock's Video Settings? That way you wouldn't have to move it.

I've used 24Hz and 25Hz refresh rates while watching video. LCD displays might be different but it looks perfectly fine using my Plasma (no flickering). Windows itself isn't as "fluid" though, so I stick with 50Hz.

So, your idea of setting the monitor to 24Hz refresh is a very bad one (though actually I doubt it is actually truly letting you do that). If you live in a PAL-system area, monitors you buy should have the capability to use 50Hz (and/or whole multiples). And for you, that's what I'd set it to 50 or 100Hz refresh. Then reclock (aka SPEED UP) your 23.976 or 24 fps movies to 25 fps. If it is 29.97 from Telecined 23.976, I'd IVTC it back to 23.976 and then reclock to 25 (that's usually what the pros do with it).

It looks perfectly fine here as well with a 24 Hz refresh rate. My monitor supports the following refresh rates: 23.976p Hz, 24p Hz, 25p Hz, 29.97p Hz, 30p Hz, 50p Hz, 50i Hz, 59.94p Hz, 59.94i Hz, 60p Hz, 60i Hz. And I'm sure it's actually letting me use 24 Hz, since using the mouse, opening windows, etc is almost impossible because the cursor flickers as hell and has a huge lag. The windows look slow while opening. But during the movie it's perfect, no flickering at all.

For example, it has been the LONGSTANDING, UNIVERSAL practice to "double-flash" (or occasionally "triple-flash") film when projecting in the cinema. So while the film "runs by" at 24FPS, each frame is shown twice, with a minor gap of black in between, at a rate of 48 Hz (or "fps"). Doing without this technique results in a VERY NOTICEABLE stuttering. Why? Because of the fact that your eyes can "see" the frames change at the slow rate of 24, but NOT at the higher rate of 48 (and triple-flashing would give you 72fps).

Didn't know that. Guess the cinematic experience is out of the question now then...

I have tried, however, the smooth motion option on madVR (that, according to my understanding, duplicates the frames to achieve the effect) and holy hell, that's a smooth playback. But the image loses a lot of detail, so it's not really for me.

Now, I have something weird going on. When I try to watch a 29.97 FPS video, ReClock shows this information:



Why is it reaching ReClock with 59.94 FPS? This happens with every video at 29.97 FPS.

[hello_hello]

Have you tried to choose your TV as the preferred screen on ReClock's Video Settings? That way you wouldn't have to move it.

I completely forgot that setting was there. The trouble is Windows sees the TV as being there even when it's switched off (unless I unplug it), so because I don't always have the TV switched on when opening video on the PC, it might get annoying. I'll have a play with it though.

It looks perfectly fine here as well with a 24 Hz refresh rate. My monitor supports the following refresh rates: 23.976p Hz, 24p Hz, 25p Hz, 29.97p Hz, 30p Hz, 50p Hz, 50i Hz, 59.94p Hz, 59.94i Hz, 60p Hz, 60i Hz. And I'm sure it's actually letting me use 24 Hz, since using the mouse, opening windows, etc is almost impossible because the cursor flickers as hell and has a huge lag. The windows look slow while opening. But during the movie it's perfect, no flickering at all.

I've never tried it with anything other than my Plasma, but Plasma TVs "flash" the pixels rather than keeping them constantly lit. It's called "subfield refresh rate" or something along those lines. So at a refresh rate of 60Hz, the TV's only refreshing the picture 60 times per second, but the pixels are flashing 10 times (I think) each refresh, hence Plasma TVs sometimes being advertised as having some form of 600Hz refresh rate, when in reality it's only 60Hz.
I've no idea if the "subfield" refresh rate is constant or changes when the refresh rate changes, but I suspect it's the former, so I also suspect the only difference in the way a Plasma TV would display video at 24Hz vs 60Hz would be the lack of "NTSC judder". I'm just theorising though as I haven't experimented with low refresh rates much myself, and I've no idea how LCD TVs display video at low refresh rates.

Why is it reaching ReClock with 59.94 FPS? This happens with every video at 29.97 FPS.

I'm not sure about that one. I didn't have a 29.970 fps video handy, so I just remuxed a small 23.976 fps video at 29.970 for testing and ReClock saw it as 29.970.