Panasonic - 1080p 24hz. Do they exist?

JeffD

Well-known Member
Whether you play back an NTSC DVD, or play an HD-DVD or Blu-Ray at 60 Hz, the issue is exactly the same. It's not a new issue, region 1 DVD's has always had this issue (unless you use a scaler with 24 or 48 Hz output, but that's another story)
I have a number of Region 1 DVD's and a DVD player and CRT TV that state they support NTSC, so I assume the DVD are being displayed at 60Hz. I've never noticed any judder on any of the dics I own, so does this mean I would not have a problem with HD not being displayed at a multiple of 24Hz? An example of a R1 disc I have is the Matrix, if I understand right then it's action films like this I should notice the issue, if at all.
 

NonPayingMember

Previously Liam @ Prog AV
I have a number of Region 1 DVD's and a DVD player and CRT TV that state they support NTSC, so I assume the DVD are being displayed at 60Hz. I've never noticed any judder on any of the dics I own, so does this mean I would not have a problem with HD not being displayed at a multiple of 24Hz? An example of a R1 disc I have is the Matrix, if I understand right then it's action films like this I should notice the issue, if at all.
Essentially correct. R1 DVDs and HD material have exactly the same 3:2 judder. R1 material is taken from 24fps film and put onto disc using a 3:2 sequence. HD material is 24fps film, on disc at 24fps, but eventually 3:2 by either the player or the display. The end result is the same, a 24 frame signal shown at 60Hz (except of course in the case where a TV does allow 24 to be shown using 2:2 or 3:3).

Odds are, if you hadn't read this forum you would not notice any judder. Of course what doesn't help, is that there is more than one way to put judder on material. I see plenty of setups where I activate a 24 frame mode (usually with a VP) and there is still judder in the image which is directly from the material itself. So in many cases you might be looking at judder in a scene, and thinking a 24p mode display is going to remove it when actually it is not...
 

Chris5

Well-known Member
Liam,

The following query only relates to DVI input
-------------------------------------------

On various posts you have claimed that the 50PF9 supports 48Hz (via VP50). Previously I have asked you whether you have seen this for yourself or just quoteing the one post that someone else put up many months ago. I am a bit suspicious of this, so I'll ask again as it is important, have you confirmed it for yourself? I'm asking because I'm probably going to get a 58PF10 myself if it will play 24Hz or 48hz smoothly.
 

NonPayingMember

Previously Liam @ Prog AV
1080p24 will AVOID rather than remove any judder that might have been introduced by a 3:2 telecine sequence. However only if the TV then replays this at a direct integer multiple of 24 i.e. 48Hz, 72Hz etc. The 3:2 telecine sequence used to get 24 frame film to 60Hz is what causes this particular kind of judder.
 

NonPayingMember

Previously Liam @ Prog AV
Can't comment on PF10 series as not seen it yet and also do not know what the new HDMI card might be able to give us and how it will process 24/48Hz inputs. If Panasonic have taught us anything it's to not automatically assume a feature from one generation will still be on the next!! (YUV via VGA lost on 7 series but back on 8, RGBcvS lost on dual-slot board, native 768p50 via VGA sort of lost on 9 and 10 series)
 

JensH

Novice Member
Chris5,

I have verified 48Hz operation via the DVI input on the 50PF9. Using a PC and Juddertest I was able to get a perfectly smooth motion of the bars. The timing settings are a bit special though. I can find them tonight and post it here.
The problem for me is that my Lumagen scaler does not work well when using this specific timing and the default timing of the Lumagen at 48Hz is not accepted by the PF9. I am trying to persuade Lumagen to fix this in the next firmware release, having provided all the details about my test to them some time ago.

At this point in time it probably makes sense to look at the PF10 instead of the PF9. If it has a specified support for 24 and 48Hz it could make life a lot easier.
 

Crosbie

Standard Member
Can I just point out that 48Hz and 72Hz aren't quite the same as 24Hz in terms of what goes on in ye olde visual cortex.

24Hz gives a 100% accurate reproduction of the light captured at a moment in time (for the duration of the film's exposure - which is likely to be much less than a 24th of a second).

Our brains fill in the gap - unless another image comes along to overrule our interpolation, e.g. the one we've already seen.

This image should not be shown to the eye for much more than the original exposure time, e.g. a 50th of a second. How long it's shown depends upon the frame rate and image persistence.

In a 24th of a second it may well be better to show a single image for the duration of a 48th of a second, than to show the same image twice a 48th of a second apart for a 96th of a second each.

The 72Hz triple image in combination with long persistence may simply end up showing for a 25th of a second what should have been shown for a 48th.

So, a true 24Hz display is possibly better than a 72Hz display - given appropriate persistence.
 

NonPayingMember

Previously Liam @ Prog AV
Viewing a 24 frame image at 24 frames is horrible. Even the cinemas use double frames on film projection (i.e. 48Hz). More about seeing the flicker from the refresh though rather than the fact that data on screen has not changed for a period of 1/24th of a second.

72Hz and 48Hz isn't always trying to get better by doing more. It's usually the some displays only do one or the other!! Although again, and usually something I saw done with CRTs, if they can handle the higher refresh rate any flicker won't be so noticeable.
 

Crosbie

Standard Member
It's a compromise between flicker and judder (temporal accuracy).

It may be that 24Hz screens end up redisplaying the same image 4 times to get 96Hz refresh.

Then again, DVD players could make some attempt at pixel flow interpolation between 24Hz images to then generate less juddery 72/96Hz.

Perhaps cinematographers might even use 100Hz HDTV cameras?

48fps IMAX?
 

NonPayingMember

Previously Liam @ Prog AV
The kind of judder everyone here complains about is where frame sequencing is odd (i.e. 3:2 to get 60Hz).

In my honest opinion we never should have gone 1080i for broadcast, and perhaps walked before we could run with 1080p24 for disc formats. 720p50 and 60 is amazing when you see it. To actually get 50/60 unique frames in a picture is just so silky smooth it's unbelieveable. I wonder if the HD-DVD and Blu-Ray format, or more importantly the current players, allow for 1080p60 on disc....
 

shortround

Novice Member
720p50 and 60 is amazing when you see it. To actually get 50/60 unique frames in a picture is just so silky smooth it's unbelieveable. I wonder if the HD-DVD and Blu-Ray format, or more importantly the current players, allow for 1080p60 on disc....
When you say 1080p60, do you mean 1080i60 deinterlaced to 1080p60? Or a true 1080p60 format? Are there even video cameras in existence that can capture 60 individual progressive frames at 1080 resolution per second?

If so, do you know of any programmes or sources that use such a format?

Thanks.
 

JensH

Novice Member
The attached file shows the settings I used for JudderTest via DVI on the 50PF9. The vertical bars were moving perfectly smooth. And the pixel mapping was 1:1.


On the Lumagen I used the following setting to get 47.95Hz and 1:1 pixel mapping. Unfortunately the Lumagen does strange things to the picture with this setting, making big jumps when panning.

VTOT 1174
VRES 1080
VSYN 30
VFRN 29

HTOT 2640
HRES 1920
HSYN 44
HFRN 528

VRATE 47.95
 

Attachments

ripclaw

Active Member
JensH, have you done any further tweaking to improve the 48Hz signal you're sending to the Panasonic panel? And has there been any word from Lumagen? I know that they're pretty busy with the Radiance. Maybe Gordon can help?
 

JensH

Novice Member
ripclaw,

I have done some testing with different timing around the values shown above, but that did not make any difference except for shifting the picture or loosing it completely.
I have also made a test, where I connected the PF9 to the DVI output of the Lumagen and a CRT computer monitor to the analog output of the Lumagen. The picture moves in big jumps, not just ordinary judder, when panning. Since this is the same on both displays my conclusion is, that the Lumagen is causing this problem. The PF9 could in principle do this, but the CRT monitor sure won't!

If I set the Lumagen to the default Lumagen timing for 48Hz, I get a totally smooth motion on the CRT monitor, but no picture on the PF9.

I have mailed back and forth with Lumagen support about this issue, but I have not got a firm commitment from them to solve the issue.
I hope it will be included in the next firmware release. If you can help Gordon, I would really appreciate it. :lease:
And I am sure other PF9/Lumagen owners would as well.
 

ripclaw

Active Member
I have mailed back and forth with Lumagen support about this issue, but I have not got a firm commitment from them to solve the issue.
I hope it will be included in the next firmware release. If you can help Gordon, I would really appreciate it. :lease:
And I am sure other PF9/Lumagen owners would as well.
I am a PF9 owner and I would really, really appreciate any further help on this issue. Gordon, please chime in.
 

Gordon @ Convergent AV

Distinguished Member
AVForums Sponsor
I've been on holiday for last 5 days. If you read the Lumagen forum you will know that they have been working on Radiance for last 6 months and will continue to do so for a short while more. At that time it is their intention to try to do some bug fixes for the Vision series before going back to work on more Radiance stuff (I htink they said another 6weeks or somethign like that before Vision work commences). Lumagen have a history of trying to fix all known bugs and to add as many features as they can. I don't believe that they will ignore this but I cannot say whether i will be in next update or any.....I am not Lumagen, I am just a distributor.
 
R

rockissponge

Guest
Related to my original post... it looks like 1080p/24hz displays have now finally been confirmed by Panasonic.

Obviously I'm very pleased, and look forward to seeing the reviews when this is released in Spring (I'm guessing April?)
 

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