Thoughts on bright room calibration with a P607 - how can I do better? - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 7 Old 04-20-2019, 07:53 AM - Thread Starter
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Thoughts on bright room calibration with a P607 - how can I do better?

Hello!


I'm attempting something as practical as it is generally inadvisable: calibrating my TV for a very bright room. It's a reality of the room and times that I view in - there's often very bright ambient window light. Even during the evenings, most viewing occurs with significant lamp light on.


I recently took a crack at this with HCFR and overall I'm pleased with the results, with a few caveats.



THE GOOD:
Skin tones and overall saturation look extremely natural. The image is rich and detailed, with very good shadow detail.


THE NOT SO GOOD:
Compression artifacts in anything below midtones are now highly visible, almost to the point of being distracting. On rare occasions, there is some banding visible that wasn't before calibration. It's my first time calibrating for BT1886, and I like what I see overall, although the slight loss of perceptual contrast takes some getting used to.


QUESTIONS:


1. Given what I've described (and the data attached and described below), is there a better calibration approach I could try?
2. Is there a technique or issue I should tackle to resolve the more visible compression artifacts and banding? Are the two even related?
3. Is there a known best practice for HDR settings on the P607? It's driving me a little nuts to have so little insight into what that HDR/DV brightness settings do.
4. Any thoughts on getting Blue saturation to behave at 100%? I wasn't able to tame that with Expert Picture Settings. I tried to access the service menu to adjust Blue Gain there, but the key patterns published online didn't work.




Attached is a report from HCFR of the results as well as the Expert Picture Settings values, and below is the setup and other settings I used.



HCFR 3.5.1.4
Patterns via MadTPG (with MadVR pre-installed)
Measurements via a new i1 Display Pro (EODIS3)
Target white: 200 cd/m2
Target gamma: BT 1886


Sources: Built in Roku Apps (Netflix, Vudu, HBO)
OSMC Kodi via a Vero 4k+ with generally high quality SDR and HDR content.



Display TCL 55P605 (P607 with a different remote)

TV Brightness: Dark
Picture Mode: Movie*
Picture Size: Direction
Local Contrast: Off during Calibration, High during use
Backlight: 20
Brightness: 50
Contrast: 100
Sharpness: 0
Color: 45
Tint: 0
Color Temp: Warm*
HDR Brightness: Dark
Dolby Vision Brightness: Dark


Thanks everyone in advance!
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post #2 of 7 Old 04-21-2019, 04:25 PM
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Quote:
Originally Posted by grizzledyoungman View Post
THE NOT SO GOOD:
Compression artifacts in anything below midtones are now highly visible, almost to the point of being distracting. On rare occasions, there is some banding visible that wasn't before calibration. It's my first time calibrating for BT1886, and I like what I see overall, although the slight loss of perceptual contrast takes some getting used to.
You may want to reduce the BT.1886 "% input offset" to around 50.
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post #3 of 7 Old 04-22-2019, 06:56 AM - Thread Starter
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Quote:
Originally Posted by Dominic Chan View Post
You may want to reduce the BT.1886 "% input offset" to around 50.
Great, I'll give that a try. To confirm that my understanding is correct, raising the input offset percentage from 0 to 50 will effectively move the 'curve' such that the picture exits black later on, yes?
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post #4 of 7 Old 04-22-2019, 07:20 AM
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Quote:
Originally Posted by grizzledyoungman View Post
Great, I'll give that a try. To confirm that my understanding is correct, raising the input offset percentage from 0 to 50 will effectively move the 'curve' such that the picture exits black later on, yes?
The HCFR default input offset is 100% ("standard" BT.1886). 0% offset is essentially gamma 2.4 with black compensation. See the attached graphs for comparison between the two, for your situation (white=216 nits, black=0.041 nits). Anything else is in between.

As you can see, you're applying a gain of 223% at 5% input, which exaggerates the compression artifacts and also reduces the visual contrast.
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Last edited by Dominic Chan; 04-22-2019 at 07:23 AM.
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post #5 of 7 Old 04-22-2019, 10:59 AM - Thread Starter
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Quote:
Originally Posted by Dominic Chan View Post
The HCFR default input offset is 100% ("standard" BT.1886). 0% offset is essentially gamma 2.4 with black compensation. See the attached graphs for comparison between the two, for your situation (white=216 nits, black=0.041 nits). Anything else is in between.

As you can see, you're applying a gain of 223% at 5% input, which exaggerates the compression artifacts and also reduces the visual contrast.
Oh, right. If I recall, the HCFR interface reads 0% at 100% input offset, right? So basically, when I performed the calibration with the setting reading 0%, I was actually using a 100% offset? Thus, a setting of 25 is 75% offset and 50 is 50 etc etc?
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post #6 of 7 Old 04-22-2019, 12:38 PM
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Quote:
Originally Posted by grizzledyoungman View Post
Oh, right. If I recall, the HCFR interface reads 0% at 100% input offset, right? So basically, when I performed the calibration with the setting reading 0%, I was actually using a 100% offset? Thus, a setting of 25 is 75% offset and 50 is 50 etc etc?
Im not sure what you mean. The input offset is a configurable value when you choose BT.1886, what you enter is what HCFR uses. There no “0% for 100%” or anything complicated like that.
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post #7 of 7 Old 04-22-2019, 12:40 PM - Thread Starter
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Quote:
Originally Posted by Dominic Chan View Post
Im not sure what you mean. The input offset is a configurable value when you choose BT.1886, what you enter is what HCFR uses. There no “0% for 100%” or anything complicated like that.
Hmm, I'll have to check the settings tonight. I remember the target being set to 0% offset. Regardless, I'll run it again at 50. Thank you!
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