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post #3241 of 3692 Old 06-29-2013, 04:23 PM
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Originally Posted by coolscan View Post

I have read that too.
But I have never seen a confirmation that it is base framerate or slow-motion or particular high-end sports cable.
Or that it is really 1080i 60Hz, same as in Europe where most HD TV channels is transmitting 1080i 50Hz, which is again is converted in your satellite/cable box to 720p and up-converted in the TV to 1080p or passed through as 1080i.
I believe they are transmitting 60 progressive frames per second at 1280x720 resolution when they are broadcasting sports.

Even if the source that the broadcaster received before transmitting in 720p was a 60 fields per second video of the sports broadcast (things in the video are captured at 60 separate moments in time), the 720p60 broadcast will still be broadcasting 60 of its (1280x720) frames (not fields) per second.
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post #3242 of 3692 Old 06-29-2013, 04:25 PM
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It's also because it's compatible with current TVs (including LCD/Plasma) and it's compatible with current broadcast cameras and previously produced TV content, as well as certain types of lighting in the UK.
TVs in Europe have been NTSC compatible for 20 years, so that's nothing new.
There are less difference between TV cameras than you think. Mostly a software difference. Remember there are the same companies that make these cameras and they are massproduced on the same assembly line, so camera compatibility is not an argument.
Not that the old cameras could be used for UHD HFR broadcast systems anyway.

The lighting is also not an argument. It is the same problem whether you shoot with 24fps or 25fps as base multiplier.
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The BBC isn't going to change to something like 72 fps since it would be totally incompatible with the previous things mentioned. For UHDTV they will also want something with better motion qualities (eg. at least 100 fps).
The multiple I showed was to illustrate the 24fps steps to 120fps and that 120fps was dividable to 60fps.
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eg. if the BBC added an UHDTV1 channel at 150 or 100 fps, they'd probably want to produce a version of that downscaled to 1080/50i so people with existing HDTVs/set top box would be able to watch the downscaled version. 72 fps would likely give a much lower quality downscale, particularly for a real-time converter.
There will be parallel channels like it is now for SD and HD and cheap set-top boxes for conversions for old TVs.
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post #3243 of 3692 Old 06-29-2013, 04:39 PM
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Originally Posted by coolscan View Post

TVs in Europe have been NTSC compatible for 20 years, so that's nothing new.
But the broadcast system isn't compatible. The broadcasters will want to output at a single frame rate, or at least a single one per channel. That's why even if the new European UHDTVs themselves are capable of receiving both 120 fps and 100/150 fps, the broadcasters will pick one (to make switching easier as well as downcoversion) and still have to transcode source material.
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The lighting is also not an argument. It is the same problem whether you shoot with 24fps or 25fps as base multiplier.
If the frame frame rates/shutter settings don't match the lights you will get flicker/strobing/interference. In the UK florescent lights will be at 50Hz. In a TV studio they could replace the lighting.
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post #3244 of 3692 Old 06-29-2013, 07:22 PM
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Originally Posted by coolscan View Post

All the Broadcast organisation* are working together for this to happen.
Having a worldwide frame rate would be great but I am very skeptical that it will happen. Also why do you think that the FOBTV has that as their goal? I couldn't find any statements about that on their website.

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Originally Posted by Chronoptimist View Post

48fps isn't cheap at all - anything that shoots or displays 48fps is new equipment. 60fps is a lot cheaper than 48fps unless you're still shooting on actual film, where framerate is directly related to cost.
Digital cameras exist today which are capable of 48 fps which is how the The Hobbit was shot. Most of those digital cameras can also do 60 fps but with a movie that has CGI every additional frame adds to the cost. I would like to think that Hollywood cares about current consumer displays but I think there is a good chance that they will care more about production cost.

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With displays that have good motion handling and low persistence, unless the framerate matches the refresh rate, you get really bad judder.
Could you explain why you think the frame rate has to match the refresh rate? You can't get rid of motion judder if you are watching video with a low frame rate (24 fps) but having a higher refresh rate wouldn't make it any worse.

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Originally Posted by Chronoptimist View Post

"600Hz" Plasmas are only displaying a 60Hz image.
A 600 Hz Plasma display turns the subpixels on and off 600 times per second. That is the refresh rate.

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Originally Posted by Chronoptimist View Post

They are counting the subfields to push the numbers up in order to try and compete with LCD which has true 240Hz panels, interpolation to ensure that each frame is different, and backlight scanning to reduce image persistence.
The reason that LCD has to do all of that is because it is a sample and hold technology. Plasma has very good motion resolution but the best current technology for motion resolution is DLP.
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post #3245 of 3692 Old 06-29-2013, 09:23 PM
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Quote:
Originally Posted by Richard Paul View Post

Having a worldwide frame rate would be great but I am very skeptical that it will happen. Also why do you think that the FOBTV has that as their goal? I couldn't find any statements about that on their website.
If you move to 300fps then you eliminate the need for standards conversion with 50/60Hz content, which is a major win for broadcasters.
Standards conversion is a horrible process that gives poor results, and as resolutions and framerates increase, is becoming increasingly costly.
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Originally Posted by Richard Paul View Post

Digital cameras exist today which are capable of 48 fps which is how the The Hobbit was shot.
Right, but prior to shooting The Hobbit, those cameras were designed for shooting slow motion effects where the intended output was still going to be 24fps.
60fps cameras and related equipment to deal with 60fps content has been around for decades.

There still aren't any 48Hz displays available for consumers.

48fps was the worst possible decision when choosing to shoot the film at high framerates - at least as far as consumers are concerned.
It may have been cost effective for the studios and makes it easy to release a 24fps version though. (but it would have been equally easy to release a 30fps version if it were shot at 60fps)
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Could you explain why you think the frame rate has to match the refresh rate? You can't get rid of motion judder if you are watching video with a low frame rate (24 fps) but having a higher refresh rate wouldn't make it any worse.
This only applies to old LCDs which behave like a sample-and-hold display, where it doesn't matter whether you are displaying 24fps content at 24Hz, 120Hz, 240Hz etc. the image will be held on the display until the next frame.
Modern LCDs use backlight scanning, interpolation, and dark frame insertion to reduce persistence and effectively turn them into an impulse-type display. Lightboost monitors are the extreme of this, where they have the lowest image persistence of any display today (best motion handling) and because they are computer monitors, they can run at 120Hz to reduce the flicker from this.
While Plasmas do have relatively high image persistence (they rely on it to work) they do still have a low enough duty cycle that the eye still perceives a repeated frame as being a separate image, rather than being a continuous image like an old LCD.

If you are watching a panning shot for example, your eye is tracking the objects as they move across the screen.
When you watch this on a display with a low duty cycle, your eye is looking for the objects to have moved the next time the display updates, but if you're displaying 24fps at 48Hz for example, for each frame, you have an extra image where everything is in the same position.
Because your brain was expecting the objects to have moved position, and they didn't, this causes really bad judder. As persistence is lowered, and/or refresh rate is increased, this judder continues to get worse.

The only solutions to this judder are either:

1. Only refresh the display when there is a new frame. This is not feasible with 24fps content, as 24Hz flickers far too much.
2. Increase image persistence. (old sample-and-hold LCD) That eliminates this type of judder, but also causes the image to appear blurred in motion.
3. Use interpolation to create new intermediate frames. This allows you to use low persistence at high refresh rates to reduce flicker, and the interpolated frames avoid judder from repeated frames. This method is less feasible on Plasmas because they cannot support 120/240Hz with high image quality (higher refresh rate = fewer subfields, which means considerably reduced gradation) and depending on the type of interpolation used, it may introduce unpleasant artifacts.
4. Shoot at higher framerates and eliminate judder at the source. 300fps video at 300Hz should be flicker and judder free. (with low persistence displays, 120Hz still noticeably flickers)


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Originally Posted by Richard Paul View Post

A 600 Hz Plasma display turns the subpixels on and off 600 times per second. That is the refresh rate.
A "600Hz" Plasma is a 60Hz display which uses 10 subfields per frame.
This is because Plasma cannot adjust the brightness of its pixels - they are either on or off. So the way an image is drawn is that the brightness is modulated over the course of several subfields with weighted durations. (e.g. 0, 1, 2, 4, 8, 16, 32, 64, 128, 256)

Yes, technically the panel is being updated 600 times every second - but it is not equivalent to a 600Hz display. An individual subfield does not make up an image.


http://www.avsforum.com/forum/www.youtube.com/watch?v=tGpdah32n3c

A "2500Hz" or "3000Hz" Plasma does not update the panel 2500/3000 times a second. That number is referring to how quickly the panel can be addressed, to try and reduce the effective duty cycle and improve motion handling.
They try and compress the subfields into an 0.4 or 0.33ms timeframe, rather than over the entire course of the frame. (16.7ms)
s70Zavi.jpg
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The reason that LCD has to do all of that is because it is a sample and hold technology. Plasma has very good motion resolution but the best current technology for motion resolution is DLP.
Modern LCD is not sample-and-hold. And Lightboost monitors have the best motion handling available today.
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post #3246 of 3692 Old 06-30-2013, 04:20 AM
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Having a worldwide frame rate would be great but I am very skeptical that it will happen. Also why do you think that the FOBTV has that as their goal? I couldn't find any statements about that on their website.
The points on the website isn't very clear.
First point on the Memorandum of Understanding (pdf) says;
Considering:
• that from monochrome to colour, and from analogue to digital, television technology has
undergone revolutionary changes. In the analogue age, colour television technology
fragmented into three major systems (PAL, NTSC and SECAM, with many subvariations).
In the digital age, the splintering has continued across the globe with
multiple, separately developed digital systems.
While television has prospered, it has not been possible for the world to take full advantage of the convenience and economies of scale of a single broadcast standard.

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Originally Posted by Chronoptimist View Post

There still aren't any 48Hz displays available for consumers.
That is just a software decision of locking 48fps. The refreshrate can be 120Hz or 240Hz or any even multiplier of 24/48 as it is today.
When Blu-Ray and HD-DVD was released, only on Sony TV could lock to 24fps playback. Now most TVs can do that.
Look what they was able to do with 3D TV with double and triple flash, it is not complicated.
Remember that we speak now of future TVs.
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48fps was the worst possible decision when choosing to shoot the film at high framerates - at least as far as consumers are concerned.
It may have been cost effective for the studios and makes it easy to release a 24fps version though. (but it would have been equally easy to release a 30fps version if it were shot at 60fps)
This only applies to old LCDs which behave like a sample-and-hold display, where it doesn't matter whether you are displaying 24fps content at 24Hz, 120Hz, 240Hz etc. the image will be held on the display until the next frame.
The Hobbit is a movie made for Cinema display and as it is a movie they keep to movie framerates to be able to show the movie in cinemas that hasn't upgraded to 48fps, and print to film
There was also no 48fps 2D version of the movie shown in cinemas (which would have been much more interesting to see than the 48fps 3D version).
Movie makers do not care about the global framerate mess of Broadcasters, they have always had their global framerate standard which is 24fps shown whit 48Hz double flash for several decades already.
If the movie had been shot at 60fps it would have been incompatible with all cinema equipment all over the world and would have to be transcoded to be shown in most cinemas.
Even BD doesn't have 30/60fps (or 48fps) in it's standard.

If Cameron shoots Avatar in 60fps he will break with the global cinema standard and use a television framerate that is only used in some few countries of the world and would have to do a lot of converted versions of the movie to fit on analogue film projections, BD releases and TV releases for PAL countries. I doubt that will happen.

If PAL broadcasters think about going for 100fps or 150fps for a future broadcast, and NTSC broadcasters go for 120fps, the PAL broadcasters would be better off for compatibility to go for 125fps.
Then 120fps broadcasts only needs to create and insert five more frames (easily done with today's software) in the transcode of 120fps streams to broadcast in future PAL broadcast systems.
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post #3247 of 3692 Old 06-30-2013, 06:58 AM
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Originally Posted by coolscan View Post

Even BD doesn't have 30/60fps (or 48fps) in it's standard.
BD has 1920x1080/60i (which can store 30 fps content. It would also be fine for a 60 frame per second (stored in fields) film too, as long as it was in 2D)
BD has 1280x720p60 (which can store 60 fps content and 30 fps content and 3D content).

So BD does have 30/60 fps in it's standard.
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the PAL broadcasters would be better off for compatibility to go for 125fps.
Which would be useless for them down-converting their own broadcasts for their HDTV channels.
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post #3248 of 3692 Old 06-30-2013, 07:36 AM
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Which would be useless for them down-converting their own broadcasts for their HDTV channels.
Why?
25fps x 5 = 125.
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post #3249 of 3692 Old 06-30-2013, 08:13 AM
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Originally Posted by Chronoptimist View Post

If you move to 300fps then you eliminate the need for standards conversion with 50/60Hz content, which is a major win for broadcasters.
The amount of light needed for the camera sensor becomes a major issue at that frame rate, costs related to decoding and processing 300 fps video would be much higher, and the perceived benefit would be very small. The idea of a worldwide frame rate sounds nice but I think it is more likely we will end up with 100 fps for PAL regions and 120 fps for NTSC regions.

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Right, but prior to shooting The Hobbit, those cameras were designed for shooting slow motion effects where the intended output was still going to be 24fps.
They were RED Epic cameras and here is a link to a RED article about The Hobbit.

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Originally Posted by Chronoptimist View Post

If you are watching a panning shot for example, your eye is tracking the objects as they move across the screen.
When you watch this on a display with a low duty cycle, your eye is looking for the objects to have moved the next time the display updates, but if you're displaying 24fps at 48Hz for example, for each frame, you have an extra image where everything is in the same position.
Because your brain was expecting the objects to have moved position, and they didn't, this causes really bad judder. As persistence is lowered, and/or refresh rate is increased, this judder continues to get worse.
Where did you read about this? The principle of increasing the refresh rate to reduce flicker has been around for a very long time and has been used for many decades in movie theaters.

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Originally Posted by Chronoptimist View Post

...
Yes, technically the panel is being updated 600 times every second - but it is not equivalent to a 600Hz display. An individual subfield does not make up an image.
Having all the pixels turn on and off 600 times per second sounds like the refresh rate to me and just because they have different duration lengths doesn't change that. I am bothered by fluorescent lighting (which has a flicker frequency of 120 Hz) but I have never had any problem with Plasma displays. 600 Hz Plasma displays are not 60 Hz displays and based on my own experience I don't see the problem with calling them 600 Hz displays. I am curious though since you don't consider it the refresh rate what do you call it?

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Originally Posted by Chronoptimist View Post

Modern LCD is not sample-and-hold.
Most current LCD displays don't have a strobing backlight since it adds to the cost.

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Originally Posted by Chronoptimist View Post

And Lightboost monitors have the best motion handling available today.
You think that LightBoost LCD monitors are better than DLP for motion resolution? Why?

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Originally Posted by coolscan View Post

The points on the website isn't very clear.
It sounds like the goal of FOBTV is to have a single transmission system used for terrestrial broadcast but that doesn't mean they are aiming to have a single worldwide frame rate.
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post #3250 of 3692 Old 06-30-2013, 09:40 AM
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It sounds like the goal of FOBTV is to have a single transmission system used for terrestrial broadcast but that doesn't mean they are aiming to have a single worldwide frame rate.
As I said before; I have never claimed that they have a global framerate as an agenda.
At the same time; If they have the aim of a global broadcast system, then the obvious would be that the system had the same framerate globally, because the difference in framerate is the largest and most costly part of exchanging programming between systems today.

When you set out to make something new, you discard all that was before and settle for the best solution. A transition period would have dual channels.
Backwards compatibility with earlier broadcasts are not necessary because very little of broadcasts have a long life of interest, the content with the longest interest are some TV series which often have been shot on film or more recently on digital cameras and often with 24fps. The life of the most popular series are seldom more than a decade before they are archived for good.

Like many film makers that have been shooting Stock Footage on on high quality SD video cameras and now find that the material they thought the could earn money on for decades to come have no more sales value.

The content with most longevity are movies, so the most sensible thing is to merge Movie and Broadcast framerates.

Whether the people working on new Broadcast standards are able to be forward thinking enough to create a quality global solution and standard for all moving images is the big question.
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post #3251 of 3692 Old 06-30-2013, 10:10 AM
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I watched the new Sony 4k at Best Buy the other day. Was surprised that it was an LED screen and not plasma. Any good explanations for that. I thought that Plasma was inherently the better screen for its deeper blacks. While I intend to get the new Panasonic ZT 65" , I thought the Sony images were beautiful. Of course, they were using 4k source material that is available to most.
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post #3252 of 3692 Old 06-30-2013, 10:57 AM
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Originally Posted by coolscan View Post

Why?
25fps x 5 = 125.
Because it's not divisible by 50. 50i (the format used for current HDTV in the UK) is capable of twice the temporal resolution of 25p..
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post #3253 of 3692 Old 06-30-2013, 11:30 AM
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Because it's not divisible by 50. 50i (the format used for current HDTV in the UK) is capable of twice the temporal resolution of 25p..
Interlaced video is a old relic from the age of CRT TV. They should scrap the whole interlace system, and thereby the 50i, it has really no place in the digital age.
It would be very sad if they started transmitting interlaced UHD broadcasts. frown.gif
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post #3254 of 3692 Old 06-30-2013, 11:58 AM
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Could you explain why you think the frame rate has to match the refresh rate? You can't get rid of motion judder if you are watching video with a low frame rate


Judder comes in when each frame is strobed multiple times (to avoid low frame rate flicker). Frames repeat, motion repeats and double images form on the eye. It's literally seeing double. One strobe per frame solves the problem very nicely (FPS = Hz). It's a common misconception that low frame rates are the cause of judder. Low frame rates actually don't judder at all. The flicker can be annoying but flicker is not a temporal error causing double images to form (i.e. judder).

When Hz are way higher than the frame rate (e.g. 600Hz) judder disappears. The eye no longer distinguishes each individual strobe. Good right? But what you see now is one long continuous frame and that amounts to sample and hold. You've simply substituted blur in for judder. Motion resolution is not much better. That's why I never considered most plasmas that much better for motion. Best solution is to always let fps = Hz

Here's what it looks like when fps do NOT equal Hz...

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Originally Posted by borf 
Low frame rates actually don't judder at all
Not all true. Low frame rates do have a type of background judder (peripheral judder) I see when not motion tracking.
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post #3255 of 3692 Old 06-30-2013, 04:11 PM
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Originally Posted by coolscan View Post

Interlaced video is a old relic from the age of CRT TV. They should scrap the whole interlace system, and thereby the 50i, it has really no place in the digital age.
It would be very sad if they started transmitting interlaced UHD broadcasts. frown.gif
I'm not asking them to start, and don't want them to start to. I think we should have the highest progressive frame rate(s) and no interlace for future UHDTV standards, but also to ensure that existing content remains shown at it's correct, original temporal resolution, with no increased judder (such as pull-down judder). I'm saying the downconverted version for existing HDTVs needs to be no worse than 50Hz. They can currently get 50Hz, so they shouldn't have to now have everything 25Hz and twice as juddery.

Ther BBC article says "there’s now a growing consensus that the 50 Hz community needs a high frame rate standard based on a multiples of 50 fps.". (50, not a multiple of 25).
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post #3256 of 3692 Old 06-30-2013, 09:20 PM
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Originally Posted by coolscan View Post

The content with most longevity are movies, so the most sensible thing is to merge Movie and Broadcast framerates.
That is the most logical thing to do but frame rate is an issue that involves money. 120 fps would be more expensive for PAL broadcasters and that is the reason that not a single PAL broadcaster has announed plans to use it. Long term it makes perfect sense to have a worldwide frame rate but broadcasters are concerned with the short term costs. Broadcasters will most likely follow the cheaper path.

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Judder comes in when each frame is strobed multiple times (to avoid low frame rate flicker). Frames repeat, motion repeats and double images form on the eye. It's literally seeing double.
The reason that motion judder occurs is because of low frame rate video. 24 fps has motion judder since you are only seeing 24 different images per second. A display could repeat the images 100 times each but you would still see motion judder.

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It's a common misconception that low frame rates are the cause of judder.
What problems do you think are caused by low frame rate video?

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Low frame rates actually don't judder at all.
LCD could do 24 fps at 24 Hz since it is a sample and hold technology but there is no point in doing that. Low frame rate video causes motion judder.

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When Hz are way higher than the frame rate (e.g. 600Hz) judder disappears. The eye no longer distinguishes each individual strobe. Good right? But what you see now is one long continuous frame and that amounts to sample and hold. You've simply substituted blur in for judder. Motion resolution is not much better. That's why I never considered most plasmas that much better for motion. Best solution is to always let fps = Hz
There are a lot of anti-Plasma myths on the internet. 600 Hz Plasma displays can't get rid of motion judder from low frame rate video but what they do get rid of is flicker. Motion judder and flicker are two different issues.
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post #3257 of 3692 Old 06-30-2013, 11:01 PM
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Originally Posted by Richard Paul View Post

The reason that motion judder occurs is because of low frame rate video. 24 fps has motion judder since you are only seeing 24 different images per second. A display could repeat the images 100 times each but you would still see motion judder.
There is judder inherent to low framerates such as 24fps. Motion only starts to appear fluid to me at ~50fps, and higher is preferred.
Repeated frames are also a source of judder, and this becomes increasingly worse as the duty cycle decreases. The only scenario where repeating frames does not introduce judder, is a sample-and-hold display like an old LCD.

As the duty cycle decreases, the judder from repeated frames gets worse. Plasma has a duty cycle below 50% (it varies depending on the display, but I seem to remember around 35-50%) and you will often find console gamers (where most games are 30fps @ 60Hz) complaining of double-images when switching to a plasma display.

Move to a display where the duty cycle is only 10% (I believe this is the case for Lightboost displays) and you will have extremely good motion clarity, but judder will be very bad if you are repeating frames.

For displays with very good motion handling properties, the framerate must match the refresh rate to avoid judder, and you need high refresh rates to avoid flicker. Even at 120Hz, Lightboost displays flicker noticeably.
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LCD could do 24 fps at 24 Hz since it is a sample and hold technology but there is no point in doing that. Low frame rate video causes motion judder.
Modern LCD does not behave like a sample-and-hold display.
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Originally Posted by Richard Paul View Post

There are a lot of anti-Plasma myths on the internet. 600 Hz Plasma displays can't get rid of motion judder from low frame rate video but what they do get rid of is flicker.
The "600Hz" number has nothing to do with reducing flicker. It's due to the fact that the only way Plasmas can modulate pixel brightness is to strobe the pixels on and off very rapidly.
Plasmas have a more obvious flicker than CRT does to my eyes due to the flicker frequency of the PWM driving varying depending on the pixel brightness, whereas CRT flicker is at a constant rate and you get used to it.
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post #3258 of 3692 Old 07-01-2013, 05:12 AM
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Originally Posted by Joe Bloggs View Post

Ther BBC article says "there’s now a growing consensus that the 50 Hz community needs a high frame rate standard based on a multiples of 50 fps.". (50, not a multiple of 25).
You are talking "passed each other". He is really not being accurate, because what he is really referring to is 50i. There are no 50fps project framerate in PAL image capture, it is always 25fps project framerate. Editing PAL content (maybe exception of Live mixing from cameras that capture interlaced) the editor project framerate will always be set to 25fps.

Here is some excerpts from TECHNICAL STANDARDS FOR DELIVERY OF TELEVISION PROGRAMMES TO BBC (pdf).
Other material can be found here.

2.1 High Definition Format
All material delivered for UK HD TV transmission must be:
  • 1920 x 1080 pixels in an aspect ratio of 16:9
  • 25 frames per second (50 fields) interlaced - now known as 1080i/25.
  • colour sub-sampled at a ratio of 4:2:2
The HD format is fully specified in ITU-R BT.709-5 Part 2.

2.1.1 Origination
Material may be originated with either interlaced or progressive scan.
Interlaced and progressive scan material may be mixed within a programme if it is required for editorial reasons or the nature of the programme requires material from varied sources.

2.1.2 Post-production
Electronically generated moving graphics and effects (such as rollers, DVE moves, wipes, fades and dissolves) must be generated and added as interlaced to prevent unacceptable judder.

2.1.3 Film motion or ‘film effect’
It is not acceptable to shoot in 1080i/25 and add a film motion effect in post-production. Most High Definition cameras can capture in either 1080i/25 or 1080p/25. Where film motion is a requirement, progressive capture is the only acceptable method.

2.1.4 Field dominance
Cuts in material must happen on frame boundaries (i.e. between field 2 and field 1). Motion on psf material must always occur between field 2 and field 1 (i.e. field 1 dominance).
Note - It is possible to shoot material at 1080p/50. If this is done, the correct 2-frame marker phasing must be maintained when down-converting to 1080i/25 or 1080psf/25.

2.11 Standards Conversion
When standards converted material is included in a programme, Motion Compensation (sometimes known as Motion Predictive or Motion Vector) standards conversion is required.
Currently speed change is the preferred method of changing between 24fps (including 23.98) and 25fps standards. Due attention must be given to the audio.
Use of non-linear editing platform hardware or software standards conversion is not permitted for whole programmes but may be used for short inserts at the discretion of the broadcaster.
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post #3259 of 3692 Old 07-01-2013, 07:00 AM
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Originally Posted by Richard Paul View Post

The reason that motion judder occurs is because of low frame rate video.

Have you ever seen low frame rate video though. Displays operate @ 60fps, movies are 48fps (double strobed). I doubt many have. Low frame rates strobe badly but remain smooth (as long as motion is slow)

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Originally Posted by Richard Paul View Post

What problems do you think are caused by low frame rate video?

Flicker and brightness. Of course with extremely low fps, the brain finds it hard to interpret motion, things seem to strobe, and the "wagon wheel" effect gets really bad..but frame rates that low have not been a concern for decades. You could call all those "temporal disturbances". I think judder, as most people are used to seeing it, is a temporal error that still exists. It's not caused by low frame rates. That's really only my interpretation and I don't say anybody is wrong for having a different one. There is no standard definition for "judder" afaik.
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post #3260 of 3692 Old 07-01-2013, 08:59 AM
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Originally Posted by borf View Post

Have you ever seen low frame rate video though. Displays operate @ 60fps, movies are 48fps (double strobed). I doubt many have. Low frame rates strobe badly but remain smooth (as long as motion is slow)
Flicker and brightness. Of course with extremely low fps, the brain finds it hard to interpret motion, things seem to strobe, and the "wagon wheel" effect gets really bad..but frame rates that low have not been a concern for decades. You could call all those "temporal disturbances". I think judder, as most people are used to seeing it, is a temporal error that still exists. It's not caused by low frame rates. That's really only my interpretation and I don't say anybody is wrong for having a different one. There is no standard definition for "judder" afaik.
Right term is double flash and it is not 48fps but 48Hz where each frame from 24fps is refreshed twice before next frame is displayed.
Motion Judder comes from low framerate, like 24fps, (and so does strobing) combined with camera panning, or objects moving horizontal over the screen of a stationary camera, of that there is no discussion.
So your earlier post that Motion Judder does not come from low framerate/24fps must be based in ignorance.
It is a fact which you can not keep arguing against.
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post #3261 of 3692 Old 07-01-2013, 10:05 AM
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Again how do you know if you haven't seen low fps. 48fps "double flashed" is probably the lowest most have seen and that doesn't count because it's not true 48fps...the double flash makes it judder. True 48fps is perfectly smooth. I've seen it. 720p60 is probably the lowest.
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post #3262 of 3692 Old 07-01-2013, 12:28 PM
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Originally Posted by coolscan View Post

You are talking "passed each other". He is really not being accurate, because what he is really referring to is 50i. There are no 50fps project framerate in PAL image capture, it is always 25fps project framerate. Editing PAL content (maybe exception of Live mixing from cameras that capture interlaced) the editor project framerate will always be set to 25fps.
Imagine they've shot something at 50i. An object's motion is captured with 50 captures per second. If they want a simple way to incorporate that footage into a progressive scan format that retains the motion captured originally, they would need a progressive scan format that is 50 or a multiple of 50.

This is like what happens with a sports broadcaster if they take 50i source material to broadcast at 720p50. And also, a good 50Hz LCD TV that de-interlaces 50i to 50p - though nowadays LCD TVs are 100Hz or above - though you don't see 125Hz LCD TVs.
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post #3263 of 3692 Old 07-01-2013, 01:38 PM
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Originally Posted by coolscan View Post

You are talking "passed each other". He is really not being accurate, because what he is really referring to is 50i. There are no 50fps project framerate in PAL image capture, it is always 25fps project framerate. Editing PAL content (maybe exception of Live mixing from cameras that capture interlaced) the editor project framerate will always be set to 25fps.
There is plenty of 50fps PAL content broadcast.

50i can be either 25fps at full resolution, or 50fps at half resolution.
60i can be 30fps full resolution, 60fps half resolution, or 24fps using 3:2.
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Originally Posted by coolscan View Post

Right term is double flash and it is not 48fps but 48Hz where each frame from 24fps is refreshed twice before next frame is displayed.
Motion Judder comes from low framerate, like 24fps, (and so does strobing) combined with camera panning, or objects moving horizontal over the screen of a stationary camera, of that there is no discussion.
Try watching 60fps content on a 120Hz Lightboost monitor. Repeated frames absolutely add judder - the problem is not solely caused by low framerates.
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post #3264 of 3692 Old 07-01-2013, 02:29 PM
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Originally Posted by borf View Post

Again how do you know if you haven't seen low fps. 48fps "double flashed" is probably the lowest most have seen and that doesn't count because it's not true 48fps...the double flash makes it judder.
No!
The double flash is 48Hz of 24fps. The double flash is done to make 24fps judder less. So the double flash doesn't make it judder.
Quote:
True 48fps is perfectly smooth. I've seen it. 720p60 is probably the lowest.
True 48fps capture judder less, that is one of the reasons for using HFR, and should be displayed with double flash 96Hz or more to eliminate judder even more.
Try to stick to the right terms and don't mix 48fps and 48Hz double flash as you do.
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post #3265 of 3692 Old 07-01-2013, 03:02 PM
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Originally Posted by Joe Bloggs View Post

Imagine they've shot something at 50i. An object's motion is captured with 50 captures per second. If they want a simple way to incorporate that footage into a progressive scan format that retains the motion captured originally, they would need a progressive scan format that is 50 or a multiple of 50.

This is like what happens with a sports broadcaster if they take 50i source material to broadcast at 720p50. And also, a good 50Hz LCD TV that de-interlaces 50i to 50p - though nowadays LCD TVs are 100Hz or above - though you don't see 125Hz LCD TVs.

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Originally Posted by Chronoptimist View Post

There is plenty of 50fps PAL content broadcast.

50i can be either 25fps at full resolution, or 50fps at half resolution.
60i can be 30fps full resolution, 60fps half resolution, or 24fps using 3:2.
Try watching 60fps content on a 120Hz Lightboost monitor. Repeated frames absolutely add judder - the problem is not solely caused by low framerates.
You guys are arguing in circles.
That displays judder more on a high Hertz display is not an argument here. The judder starts at the framerate capture and that TVs can make it judder more is just because the TVs processing (and all the processeses the video stream goes through before reaching the display) makes the original judder worse.

I just tested this with a new satellite HD receiver, setting it to 1080p with the result of extream judder. 1080i worked fine, but sometimes what should have been seen as judder came out as banding instead. This was on a projector 135" screen for European HD channels.

As to the 50fps material you claim there are a lot of; As you saw in the BBC guidelines, you can film at 50fps but it also noted it had to be transcoded to 25fps.

I doubt there are much 50fps progressive filmed so it would be any problem to transcode this for future UHD channels.

And there we come to essence of this discussion where you guys just repeat yourselves in circular dead arguments that really has nothing to do with what we discuss and which gets you nowhere.

We are discussing future framerates and the possibility of a new global broadcast system.

If the previous use of 50i/p is a hindrance for settling on a global framerate for all systems, then they can just drop using 50 whatever for the new system.

What you guys seems to forget in your eagerness for defending 50i/p/fps is that a new global TV system based in UHD-1 and UHD-2 requires new cameras, new displays (the 4K display being released now isn't usable for much UHD broadcast as they don't have receiver modules for it and no HDMI 2.0) and new transmitter hardware and software.

As I have mentioned many times now; There will be a transition period with dual channels like it is now for SD and HD. If someone still want to film in 50i with old equipment in the transition period, they just wont show that programming on the UHD channel.

So when all equipment is new from capture through to display there are no good reasons that 50i/p/fps should have a place in any argument or discussion of a new broadcast standard, even if they still continues to use two separate broadcast systems like they do now.

Which means that PAL can settle for a 125fps basis and NTSC can settle for a 120fps basis which makes transcoding between the two systems a little easier, but still would show that they are stupid to agree on the same frame basis.

If PAL can't agree with NTSC for a framerate they still would have 100fps,125fps and 150fps to choose from, and can therefore just exclude 50 whatever if it doesn't fit in.
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post #3266 of 3692 Old 07-01-2013, 03:16 PM
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Originally Posted by coolscan View Post

The double flash is 48Hz of 24fps. The double flash is done to make 24fps judder less. So the double flash doesn't make it judder.
It is done to make it flicker less.
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Originally Posted by coolscan View Post

You guys are arguing in circles.
You're the one that keeps insisting that repeating frames does not introduce judder.
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Originally Posted by coolscan View Post

That displays judder more on a high Hertz display is not an argument here. The judder starts at the framerate capture and that TVs can make it judder more is just because the TVs processing (and all the processeses the video stream goes through before reaching the display) makes the original judder worse.
It is nothing to do with processing. When you display a low framerate at a high refresh rate, you are introducing judder for each frame repeat, up to the point at which the display is effectively a sample-and-hold display.

This is why, when you display 60fps - which most people would agree does not judder (at least not significantly) at a 120Hz refresh rate, you start to see judder.
It has nothing to do with "TV processing" - a Lightboost monitor is not doing any, and you will see the same thing with 60fps at 120Hz on a CRT as well.
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As to the 50fps material you claim there are a lot of; As you saw in the BBC guidelines, you can film at 50fps but it also noted it had to be transcoded to 25fps.
Anything shot natively in 50i has 50 unique images per second. That is equal to 50fps at half resolution. You cannot convert this to 25p.
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post #3267 of 3692 Old 07-01-2013, 03:54 PM
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Originally Posted by coolscan View Post

No!
The double flash is 48Hz of 24fps. The double flash is done to make 24fps judder less. So the double flash doesn't make it judder.
Try to stick to the right terms and don't mix 48fps and 48Hz double flash as you do.

Sorry that's completely backwards. I don't agree.
48(fps) was used out of term before. I agree.
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post #3268 of 3692 Old 07-01-2013, 06:29 PM
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Originally Posted by Chronoptimist View Post

Try watching 60fps content on a 120Hz Lightboost monitor. Repeated frames absolutely add judder - the problem is not solely caused by low framerates.

Yes, in fact the first TVs with motion interpolation were not LCDs - they were European CRT TVs which displayed 50Hz content at 100Hz (because 50Hz flicker annoys some people).
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post #3269 of 3692 Old 07-01-2013, 07:16 PM
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Yes, in fact the first TVs with motion interpolation were not LCDs - they were European CRT TVs which displayed 50Hz content at 100Hz (because 50Hz flicker annoys some people).
Are you sure? Do you have a source that says 100Hz CRTs used motion interpolation?
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post #3270 of 3692 Old 07-01-2013, 07:59 PM
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I believe Philips did indeed have some CRTs using their "Natural Motion" technology, which was motion interpolation.
But 100Hz CRTs which displayed 50Hz content with repeated frames (rather than interpolation) were certainly common in Europe, and a frequent complaint was that motion handling was poor on them compared to 50Hz sets.


In my post regarding CRTs and Lightboost monitors displaying 60fps at 120Hz, I am not talking about 120Hz interpolation however - just repeated frames.
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