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Old 11th January 2021, 16:13   #1434  |  Link
chros
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Quote:
Originally Posted by chros View Post
Fall values also can be exponential, yes
But I created those only up until 400 because we want to test "normal" content first, right?

Quote:
Originally Posted by aron7awol View Post
This obviously depends on the specified DPL/DTN combo, but I'm confident the target exceeds DPL with FALL of 250 on the vast majority of combos that people run. ...
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You're running 700/60 and 800/?
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Don't forget our DTNs all increased (or should have) with the "don't add peak nits" option, which is where this formula applies. So I don't think any of us are running low (<60) DTNs anymore with that option. You might be the lowest at 700/60.
I use 700/60, 800/59. And yes, obviously "don't add peak nits" option is enabled.
We want to experiment with the same settings, to avoid confusion, like this!

So, what about 800/75 to start with? If you like other pair instead, we can use that. But in this case we only have to take a look at 1 row in that sheet.
Along with these options:
- "don't add peak nits" enabled
- "avgHL ceiling" disabled (for "normal content" we don't need it)

Quote:
Originally Posted by aron7awol View Post
I think I'd kind of summarize my interpretation of the whole operation of DTN and the avgHL ceiling as follows:

1. Frame peak is pretty much irrelevant. DTN doesn't even look at it, and it can be way higher than DPL without the highlights driving FALL high enough for DTN to kick in. Most frames including those with really bright highlights fall into this category, and DTN does nothing. madVR TMs to DPL.
Yes, that's the case for now, but the question is whether this is allright? We agree that having 300 FALL with 600 frame peak is not the same as having it with 1300 frame peak.
That's why I though about CLL, but maybe your 3. point is better for this.

Quote:
Originally Posted by aron7awol View Post
3. Within this subset of frames with higher FALL, there is an additional consideration. Is this whole frame "bright" (I believe currently hardcoded to >100 nits but would love to be able to change this)
I also think it's 100 nits, the brightness histogram (top right on the OSD) display these as grey (first half of the histogram, 0-63).
And as I said, probably it needs to be some dynamic detection for this, based on the content.

Quote:
Originally Posted by aron7awol View Post
or does it have dark/normal areas and also quite big and bright areas? This is where the avgHL ceiling comes in. avgHL is always >= FALL, but on frames where pretty much the whole frame is bright, it will be closer to FALL, and on frames where there are normal/dark areas, it will be significantly higher than FALL. I think essentially we are trying to account for frame dynamic range differences, and this helps us, to a limited extent, to differentiate within these high-FALL frames between those that have more or less dynamic range. And those with less dynamic range probably don't need as high of a target, and since avgHL will be close to FALL in these cases, the lower ceiling multiplier will result in a lower target than the normal target arrived at via the higher FALL multiplier. So we can try to choose a FALL multiplier that results in proper targets for the higher dynamic range high-FALL frames, but also an avgHL multiplier that results in proper (lower) targets for the lower dynamic range high-FALL frames.
Good idea, the histogram can help with determining this (instead checking CLL).

Quote:
Originally Posted by aron7awol View Post
Anyway, I'm not sure avgHL ceiling is the optimal way to account for category 3 and these dynamic range differences (and this is why I was thinking about things like stddev/percentile as potentially much better ways)
What do you mean about stddev? (There's a FALL Stddev on OSD as well, but no one knows what it shows )

Quote:
Originally Posted by aron7awol View Post
but having the 100 nits "highlight" definition adjustable might help.
This has to be dynamic, we don't want to use profiles for this.

Quote:
Originally Posted by aron7awol View Post
I actually think the best way to hone in the optimal formulas would be to do a sort of case study where we pick a number of higher-FALL frames from a movie or different movies that sort of fall into these different scenarios, and each of us goes to each of these frames and finds their preferred target. Then based on this result we should be able to come up with a combination of settings and/or an improved formula that gets us close to these targets automatically in each case.
Hmm, that's one way, but I'm not sure it would be fruitful.
What about this for now?
- select 1 title/scenes with appropriate frames for testing
- we will check it together
- try to draw the same (!) conclusion (if we won't agree what we should achieve then we don't have to work on this together )

So, I propose (for the 3rd time) The Grinch (2018).
Thoughts?
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Last edited by chros; 11th January 2021 at 16:15.
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