Is there another pattern on this disc to set/verify contrast, other than the one labeled "contrast"? I'm having trouble getting the "contrast" test pattern to work correctly. Thanks.
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Originally Posted by jimwhite /forum/post/18481224
It would be interesting to kind of turn things on its ear and map the YCbCr codes that result in "illegal" RGB codes... where are they in the color space, or are they?
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Originally Posted by Mr.D /forum/post/18480961
I can normally tell when I'm watching something (DVD/BD) on a display that is clipping at 235. Like I said try it and see rather than continually discussing it.
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Originally Posted by Jim McC /forum/post/18478659
I still don't know how to find the proper contrast setting.
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Originally Posted by PlasmaPZ80U /forum/post/18481915
Outside of the AVS calibration disc, I have yet to see any difference between super-white on and off when playing a DVD or BD movie. I'm using the YCC color space, since super-white doesn't work in RGB color space on the PS3. I might not be looking at the right scenes, but then again perhaps the difference too subtle for the average viewer to notice.
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Originally Posted by alluringreality /forum/post/18481977
The easiest way to set contrast is probably to begin by setting contrast to a very low setting so that you can see all the detail in the contrast pattern. Start turning up contrast. Keep turning up contrast until the detail in the pattern begins to disappear (or you see a color shift from pure white). Now turn contrast down until most all the detail still appears and you can't go any higher without losing detail in the contrast pattern. Without any measurement equipment this sort of a method will probably result in a reasonably high contrast setting that is still likely to deliver all the detail in the original image.
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Originally Posted by PlasmaPZ80U /forum/post/18481915
Outside of the AVS calibration disc, I have yet to see any difference between super-white on and off when playing a DVD or BD movie. I'm using the YCC color space, since super-white doesn't work in RGB color space on the PS3. I might not be looking at the right scenes, but then again perhaps the difference too subtle for the average viewer to notice.
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Originally Posted by Mr.D /forum/post/18482259
I'm not familiar with the setup on a PS3 : as I'm a real gamer and own a 360
You should be able to have it setup to pass full range video from discussion on the net I've seen. Verify that first.
The difference between setting peak white at 235 or 254 is pretty massive visually to me.
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Originally Posted by gtgray /forum/post/18482429
I have only looked at ChromaPure HCFR which don't seem to work in this way but it seems to me that instead of 10 zones for grayscale, there should be 11. I know HCFR allows you to free measure. I assume ChromPure does as well.
The highest zone woud be to 109%. If RGB was in balance across the zones through 11 with gamma right for zone 10 would you not almost by definition have a correct contrast setting. You would then choose the highest luminance that you were comfortable with that conitnued to allow the grayscale to have RGB balanced and gamma right.
I don't really know, but I suspect with my set is there is a gamma spike at high saturation. Is there a simple way to calculate what the luminance of 109% saturation should be given a target gamma and the known luminance at 100% and the calibration software's indicated gamma at 90%?
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Originally Posted by dsskid /forum/post/18482104
alluringreality, I hope you don't mind me adding about the color shift.
-John
Quote:
Originally Posted by Mr.D /forum/post/18482259
I'm not familiar with the setup on a PS3 : as I'm a real gamer and own a 360
You should be able to have it setup to pass full range video from discussion on the net I've seen. Verify that first.
The difference between setting peak white at 235 or 254 is pretty massive visually to me.
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Originally Posted by sotti /forum/post/18482533
Depends on exactly what your target gamma is, but assuming it's 2.2 the...
maxY = 100% Y
Y = (1.09)^2.2 * maxY
So for 2.2 gamma it's about 20% more light than 100%.
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Originally Posted by gtgray /forum/post/18483422
Thanks Scotti,
I am assuming that if my target gamma is 2.35, I would just use 2.35 as the exponent in the above formula?
The DUO is going to give me no way to control 109% but at least I can determine if I my gamma is spiking at above white as I suspect.
Quote:
Originally Posted by alluringreality /forum/post/18481977
The easiest way to set contrast is probably to begin by setting contrast to a very low setting so that you can see all the detail in the contrast pattern. Start turning up contrast. Keep turning up contrast until the detail in the pattern begins to disappear. Now turn contrast down until most all the detail still appears and you can't go any higher without losing detail in the contrast pattern. Without any measurement equipment this sort of a method will probably result in a reasonably high contrast setting that is still likely to deliver all the detail in the original image.
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Originally Posted by Jim McC /forum/post/18485562
When you say "detail in the contrast pattern", do you mean the bars on the bottom?
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Originally Posted by PlasmaPZ80U /forum/post/18483210
UPDATE: I just saw a 3 hour Blu-ray movie (XIII: The Conspiracy) that had plenty of bright scenes and scenes with bright areas. Some of these scenes were extremely bright or had extremely bright areas. I checked super-white on/off for as many as I could sometimes zeroing in on a single frame to capture the brightest image on-screen. I found zero difference time and time again. No difference whatsoever.
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Originally Posted by Mr.D /forum/post/18486472
http://www.mastersofcinema.org/reviews/onibaba.html
In trawling about I find lots of blunt assertion from pro/semi pro practitioners that video is 16-235 and everything outside that is "illegal". However if you read the standards for rec.709 and bt.601 what they continually state is that 236-254 is defined as headroom/superwhite/excursion.
(rather than just latching on to the obvious numbers 16-235 which is where I think a lot of this confusion stems from...people like absolute numbers)
Even if you ignore the fact that YCrCb maps higher into RGB and look just at the numbers in the spec sheet the chroma planes range from 16-240.
So that leaves us with 3 possible conclusions: ( this is referring to where the values end up on your display visually)
16 is black 235 is peak white and anything else is a bad thing.
16 is black and 254 is peak white and you should show the lot.
16 is black and peak white is 240 because the chroma planes range above 235 ( ignoring the mechanics of how YCrCb maps into RGB..someone else can do the maths I tend to fall asleep...I can't help it).
Last but not least what does this mean in the real world?
Watch some material with your display setup for peak white at 235 and then watch it at 254 and see what you think and post your observations.
I'm sure we can manage to do this without having a massive punchup if we remain a little open minded.
Things we think we know about video:
black ...16
ideal display gamma in a dim environment 2.35
(assuming a range between 2.2-2.5 depending on viewing situation and display performance)
Grayscale ...D.65
(B/W notionally justifiable as D.54 from a preferential/historical perspective)
Gamut... (according to standard and display capability and metering/adjustment capability)
white... see above (personally I'm sticking with 254 until I'm persuaded differently)
Quote:
Originally Posted by Jim McC /forum/post/18485562
When you say "detail in the contrast pattern", do you mean the bars on the bottom?
Quote:
Originally Posted by Mr.D /forum/post/18486472
...
16 is black 235 is peak white and anything else is a bad thing.
16 is black and 254 is peak white and you should show the lot.
...
Last but not least what does this mean in the real world?
Watch some material with your display setup for peak white at 235 and then watch it at 254 and see what you think and post your observations.
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Originally Posted by bodosom /forum/post/18487711
I thought that when S&M looked at discs they found lots of pixels both below 16 and above 235. But I also think the percentage of such pixels is low