Should I override my EDID on TV-led?

[Akila3]

I have the TCL C935 that advertised by the vendor (TCL) that it has 2000 NITs peak brightness (2000 cd/m^2), but when I export the EDID to a file (SSH ->"echo save bin /storage/downloads/jonke-pj.bin > /sys/class/amhdmitx/amhdmitx0/edid") and decode it with AW EDID Editor
It shows me the payload of "4d4e4a725a7776" which is Max of PQ 2900 (696 cd/m^2), if I put it in CE-CPM VSVDB Payload.

But at the same time, if I load the same EDID file into the online decoder https://people.freedesktop.org/~imirkin/edid-decode/, it is showing me a different results for the same section

1. Can anyone explain? why there are different results (AW EDID Editor vs. Online Decoder)? why it doesn't match the vendor's Specs of the TV of 2000 cd/m^2 peak brightness?

2. Am I reading it correctly or I am reading it all wrong?

3. Should I override the VSVDB in CE-cpm (it is set on TV-led, so not sure if overriding has any effect, as TV-led by concept should pass the DV metadata to TV to process anyway & TV will do whatever it wants anyway)?

4. What should I set in VSVDB cd/m^2 = 2000 or based on the EDID of PQ 2900 696 cd/m^2 or PQ 2640 (385 cd/m^2) or leave it switched off?

This is my EDID file exported from CE-CPM
EDID-TV.zip

[R3S3t9999]

I don't know about questions 1-2 but the EDID/VSVDB target is only for LLDV/player-led.
In TV-LED, the TV uses its internal DV config, so changing the EDID for TV-LED won't do anything.

[Akila3]

That is what I thought, but even when in TV-led when I changed the settings to Max 2000 cd/m^2 I felt the picture was brighter.
Also when still in TV-led , when I changed the colometry from DCI-P3 to BT.2020 (under the VSVDB), there was a color change.
So my conclusion even in TV-led when switching it On, it has an effect, even though theoretically it shouldn't.
Or it's a bug. meaning if you switch on VSVDB in TV-Led, it actually renders the picture in Player-led

Both Played in Dolby Vision
This is the Picture with VSVDB set to DCI-P3 in TV-led

This is the Picture with VSVDB set to Rec.2020 in TV-led

[R3S3t9999]

I don't know about P3 vs BT.2020, but the VSVDB target can be different from the internal DV config.

You can try to disable any VSVDB CoreELEC options and use this file to test when your TV starts dimming.

• On my C2, the internal and VSVDB DV target are 810 nits, and the pattern starts dimming around 850-900 nits.

• On my Hisense TV (2000 nits 10%, 900 nits 100% + 1037 EDID), I don’t know the internal config, but I suspect it's under 1000 nits. It dims around 900-950 nits.

• On my Samsung monitor, EDID is 400 nits, and the pattern starts dimming around 400-450 nits.

[R3S3t9999]

1-Since both VSVDB and internal DV config seem to be the same, it was probably intentional, but that doesn’t make it correct.
Based on your TV's actual measurements, the target should be at least 1300 nits. It looks like they set it to 700 nits based on the 620-nit full-field measurement, which doesn’t make sense because:

• 99% of movies have an average brightness below 50 nits.

• Only a few frames (e.g., explosion flashes) exceed 100 nits average brightness.

• Small 10–25% highlights exceeding 1000 nits are common, yet due to the 700-nit target, they always get compressed, even though they could be displayed much brighter without clipping on your TV.

It doesn't make sense because For example, my C2 barely reaches 160 nits full-field, yet its DV target is 810 nits—higher than your much brighter TV. My Hisense TV also does something stupid like that. Mine has an EDID target of 1037 nits, but the internal DV config is only 900 nits but the Measurements are: 2156 nits (25%), 853 nits (full-field).

2- I haven’t tested Player-led DV with a custom target, only Player-led HDR so I don't know.

3- For Player-led HDR:

• 10–25% window measurement should be the MAX PQ value.

• MIN should be 0.

• If the target is over 1000 nits, enable "Limit VSVDB Luminance."

[Akila3]

in Player-led DV and/or HDR, the screen starts dimming at 400nits (like the Max target of 385 in DV EDID from cpm).
Only in TV-led it starts dimming at 750. this doesn't makes sense that there will be two separated EDID's or behavior...
So what does that mean? could it be that the cpm is reading wrongly the EDID? as it should have started dimming at 750 also in player-led (DV/HDR) like in TV-led.
why would there be difference?

Also I think the EDID was configured in the TV incorrectly. that is because the panel supposed to provide up to 2000nits at 5% window and around 1300 at 10% window and displayed HDR more the 1000Nits and combined full field brightness of 622Nits (was validated by HDTVtest - https://www.youtube.com/watch?v=Qi_Et184mWI&t=245s)

When setting values in VSVDB, no matter is it is player-led DV or HDR, it never dims , not even at 6000Nits on your test file.
it seems like it just locks the dimming when vsvdb is set.

This is the EDID I pulled from CE-cpm with the SSH command:

Vendor-Specific Video Data Block (Dolby), OUI 00-D0-46:
Version: 2 (12 bytes)
Supports YUV422 12 bit
Supports global dimming
DM Version: 5.x
Backlt Min Luma: 75 cd/m^2
Interface: Standard + Low-Latency
Supports 10b 12b 444: Not supported
Target Min PQ v2: 180 (0.04555910 cd/m^2)
Target Max PQ v2: 2640 (385 cd/m^2)
Unique Rx, Ry: 0.67968750, 0.30468750
Unique Gx, Gy: 0.22265625, 0.67578125
Unique Bx, By: 0.15234375, 0.05468750

[R3S3t9999]

Yes, it sounds like your edid target is 385nits. The edid-decode website is accurate, always has been with all the edid I decoded there. CPM build too is correct since it dims at 400nits with the test file. Both of your Target sounds wrong for your TV capabilities but the Edid/VSVDB and internal DV config targets can be different. EG the LG C9 has a VSVDB of 700nits and the internal DV config for TV-LED is set 600nits... Unless you're forcing lldv (which no one should do) it doesn't really matter since TV-LED will always be prioritized and the TV internal target will always be used

source

Internal config
Tmax = 600
Tmin = 0.001
From panel specification
TPrimaries = 0.6766 0.3231 0.2526 0.6822 0.1413 0.0483 0.3127 0.3290

VSVDB Related Information
vsvdb_Tmax = 700
vsvdb_Tmin = 0.0001
vsvdb_TPrimaries = 0.7080 0.2920 0.1700 0.7970 0.1310 0.0460 0.3127 0.3290

[Akila3]

1. the question is, is the EDID correct to the TV/panel or it just starts dimming at 400 (Player-led) because that is what the EDID say it should?

2. So now when the conclusion that my TV's EDID is at 700cd/m^2 (TV-led, as that is when it started dimming).
   What needs to be set in HDR Infoframe if I to chose using Player-led HDR?
   (let's assume for a moment for the discussion, my TV only supports HDR)

[R3S3t9999]

1- As I said and according to your TV brightness measurement, both of your targets (vsvdb and internal config) are incorrect and will dim more than they should.
2- edid doesn't matter in TV-LED but if you use lldv-HDR, I would use 1300/0nits target brightness with HDR infoframe that match those values: MDL 1000/1 maxcll/fall 1300/400. And enable "Limit VSVDB Luminance."