Dolby Vision now possible through MP4 Mux.

[RESET_9999]

Yes, I tested with two different TV (C8 and C2):
x700
x800m2
shield
ATV


I doubt this is intentional otherwise it would also be ignored when you play the file with the TV internal player.

[skull88]

Also, is there any chance that it is intentional for the positive lift L2 Trim to be ignored on TV-led devices if that is the case? Maybe Dolby determined that the TV should make its own decision in those cases...?

I agree with RESET, it also doesn't make sense for Dolby's own Professional Tools to generate positive trims when run automatically, if they intend for them to be ignored. I haven't seen/read any Dolby official articles or manuals mention advising against positive values on any trim adjustments when grading either, other than positive lift not being above 0.025 for letterbox content, see here: https://www.youtube.com/watch?v=AVZ7xcgeEAM

[speeddemon]

Yes, I tested with two different TV (C8 and C2):
x700
x800m2
shield
ATV


I doubt this is intentional otherwise it would also be ignored when you play the file with the TV internal player.

So the C8 & C2 don't have the issue when you're using the internal player? How about Kodi?

I want to test this from my Sony A95K to see if it behaves the same way... wondering if maybe this is an LG behavior... or is that not possible?

Does Dolby state this for a different reason?

Avoid using positive values over 0.025 on the LIFT trim control for letterboxed content. (Negative Lift values are acceptable on all versions).

Source: https://professionalsupport.dolby.com/s ... uage=en_US

[RESET_9999]

right C8 and C2 internal players do not have this bug. I haven't tested kodi but I don't see why it would be any different.

Does Dolby state this for a different reason?

yes but they still can lift up to 0.025 which is ignored by the HDMI players and if the content is full screen then there is no restriction so this cannot be the reason plus they can lift with the other trim control as well.
Also, they can use the metafier to verify or fix any lift.

[susanstone2022]

right C8 and C2 internal players do not have this bug. I haven't tested kodi but I don't see why it would be any different.

We really don't know how TV process DV signals. One possible explanation is internal player is doing LLDV.

[susanstone2022]

Yes, I tested with two different TV (C8 and C2):
x700
x800m2
shield
ATV
I doubt this is intentional otherwise it would also be ignored when you play the file with the TV internal player.

This was one of my questions in my previous post - is this metadata actually used?
L2 trims are "per-target trim metadata" - typically 100nits, 600nits, 1000nits. How would TVs or players use this data?
If the TV happens to be one of these three numbers, it can use one of them.
If the TV is 350nits, 800nits, 1500nits, 2000nits, which L2 metadata would it use? use the closest one? or extrapolation? for example, 800nits TV will use both 600nits+1000nits?

Can you see internal player output? I think Kodi can show its output. If we know what signal come out of internal player, we can do better troubleshooting.

[RESET_9999]

This was one of my questions in my previous post - is this metadata actually used?

of course, and all the trims work together in interpolation.
I did test files that can verify pretty much anything DV-related here: https://drive.google.com/drive/u/1/fold ... V0E3VVkhiC

One possible explanation is internal player is doing LLDV.

what

[susanstone2022]

of course, and all the trims work together in interpolation.
I did test files that can verify pretty much anything DV-related here: https://drive.google.com/drive/u/1/fold ... V0E3VVkhiC

Do you know any documentation on how metadata is "supposed to be" used? I see many documentations on how DV conetent is generated. However, I rarely see any documentation on how it is supposed to be used. We can only guess on how things should work or how things currently work.

One possible explanation is internal player is doing LLDV.

what

It depends on how the DV work flow on the display side, ins't it?
It needs to decode into DV data and send it for processing. For external player we know or we can guess who is doing the processing (TV-led, player-led, or combination). For internal player, do we know which part of display is doing the processing. It could be the internal player processing everything and send it for display. It is a SoC after all, not much difference than amlogic, mediatek, etc.

[RESET_9999]

We can only guess on how things should work or how things currently work.

We have all the tools we need to create or analyze any DV RPU and we understand very well how the DV metadata levels work, everything has been tested intensely in every possible way.

[skull88]

With respect, I think you're overthinking this susanstone2022, as Dolby has very clear in explaining everything about DV, through extensive documentation, how-to videos, manuals, and partner software like DaVinci Resolve also includes a deep manual explaining what all the trim adjustments do and how they should be understood and expected to be interpreted (there's a reason the Dolby DoVi license is so damn expensive, there's no hidden secrets or conspiracy here). Furthermore, you can clearly test all this, as RESET_9999 has done over many many hundreds of hours at this point, along with others like quietvoid who did all the incredible work reverse engineering Dolby Vision in the first place. How else would we even be able to know about the difference between all the players, LLDV vs TV-LED, and how it "should" look vs. when it's not if there was no understanding of the way DV works and is processed.

There is also the 4K Spears & Munsil disc available for further calibration and testing of TV-Led vs Player-Led by the likes of RESET, Vincent from HDTVTest and others in the industry. To put it most simply, just remember that Dolby Vision requires a special SDK/engine to be used and not unlike audio being able to "pass-through" to an AVR, the metadata for Dolby Vision also can "pass-through" and that's essentially what TV-Led is describing. It's technically possible some lower-end TV would not even properly license or play DV metadata but that's why folks like RESET test on multiple displays and Dolby obviously has a relationship with the likes of Sony and LG to ensure their top-end models properly implement Dolby Vision in TV-Led mode, at least with their own Blu-ray players and possibly major streaming apps.

Hopefully that makes sense, there are times to be skeptical, but this is not really one of them, as RESET, quietvoid (and Vince from HDTVTest etc.) don't work for Dolby and have put all of the labour and research required to understand and test Dolby Vision as objectively as possible, so you don't have to.

[RESET_9999]

very true..
thank's @skull88

[aboulfad]

I don't think anyone is questioning or doubting any of the DV sensei's contribs ( time, patience, shared info, knowledge & software). Speaking for myself, I think communication medium is sometimes a barrier, as a DV noob to express what I am trying to learn when it's so darn confusing. Anyway thank you & much <3 to all

PS: maybe time for a realtime chat as in discord channel could be an idea ?

[susanstone2022]

@skull88, Thank you for the reply. I appreciate all efforts and contributions @RESET_9999 made. I am just trying to make sense of his and other people's test results. These test results don't make sense to me.

When you say "Dolby has very clear in explaining everything about DV", how come the playback devices behave so differently in reality? Aren't they using the same DV SDK or DV certified SDK? Some devices are totally wrong. A specific example, in DMDreview testing, 100nits shows as 200nits in some devices. Don't the device manufactures or dolby know about this? RESET and DMDreview can run the test patterns to check if the DV is correct. Don't the device manufactures have test patterns too to check if their device are actually doing the right thing?
In my opinion, here are the possible explanations:
1. Dolby has no clear instructions on how playback device should work.
2. Manufactures don't know what they are doing and Dolby don't care either as long as they pay license fees.

I appropriate if you can share some public documentations on how playback should work. Most documentations I found are for content creation, not playback.

[susanstone2022]

@RESET_9999, I just though of an example of internal player - Fire TV (not streaming device, the TV) and Fire TV Streaming (Stick or Cube) devices as external player. In theory, would they behave differently?

[lexyz]

Hi mate, I don't if you still read this thread...

Actually, I do
At least once a month

There are still tons of amusing stuff around DoVi.

In theory, would they behave differently?

Most likely, yes