Dolby Vision now possible through MP4 Mux.

[AndreasT]

Just a heads up in case you haven't heard:
Our old and well hated friend the UGOOS AM6+ rises from the dead.

With the latest CoreELEC 20.3 Nexus version, it finally supports proper Dolby Vision FEL decoding with HD audio passthrough. I just installed it on my device (I have the AM6b+), configured audio passthrough, installed Plex Mod 4 Kodi and it just played every MKV Remux with Dolby Vision I tried. No Issues with pausing or skipping.

Source and how-to: https://www.reddit.com/r/PleX/comments/ ... _team_has/
Beware: My device did not boot from the SD card right away, I had to press the "recovery" button on the bottom of the device before powering it on. Then it booted fine - following start directly booted to CoreELEC, no need to press the recovery button again.

So does it actually apply the EL layer information, or does it just decode and throw it away?

[ultrahorst]

So does it actually apply the EL layer information, or does it just decode and throw it away?

As far as I can tell yes. I tried the usual test files first, where there is a FEL stream from another movie present, I also tried the FEL TEST ST DL P7.mp4 with the "Dolby FEL support" text encoded into the EL. The EL layer is decoded AND displayed.
I'll try watching Saving Private Ryan today - IIRC this showed anomalies when EL layer is discarded.

[dapope]

I doubt it. Was raised on my C8, and it's still raised on my C2.
C8 was worse though and the white balance trick didn't work on my end.

You're right. I just tried the test file on my CX and can see the raised black. It's so slight, I would probably have never noticed outside of test conditions. But good to know, thanks.

[RESET_9999]

@RESET_9999 I was doing some SDR to HDR conversion. When I exported the DV XML file, it has some L2 and L3 trims. Should I keep those or remove?

It's up to you. I prefer removing all the trims as they can have an undesired effect (darken or brighten too much).

made a couple of test files about that:

High peak High average : https://drive.google.com/file/d/1I1c6ob ... drive_link
mid peak high average: https://drive.google.com/file/d/1BaV3Vb ... sp=sharing
high peak low average: https://drive.google.com/file/d/1Za17C- ... drive_link
low peak low average: https://drive.google.com/file/d/1I0CDqL ... drive_link
L2 original vs generated : https://drive.google.com/file/d/1t-T2WT ... drive_link

L1 Tuning vs old algo vs madvr vs hdr10plus comparisons: https://drive.google.com/file/d/1yPXQLp ... drive_link

L3 is not a trim, its an offset to L1 and you should keep it.

You're right. I just tried the test file on my CX and can see the raised black. It's so slight, I would probably have never noticed outside of test conditions. But good to know, thanks.

You can use the white balance trick described in my excel playback sheet to fix it.
On the C8, I noticed it as soon as the screen went full black... WB couldn't fix it, only contrast adjustment did the trick
on the C2, I can notice it when the screen goes full black for at least 2-3 sec or in the ending credits... I use WB RGB -2

There are also ways to fix it when you calibrate but I don't know much about it... @chros could tell you more.

[chros]

There are also ways to fix it when you calibrate but I don't know much about it... @chros could tell you more.

You don't even have to calibrate it, just to have good eyes (or lupe), guide.
I will try out Tmin=0, have you yet?

[RESET_9999]

When trying to grade HDR in DaVinci, the preview looks washed out (I have a 4K HDR monitor).
Is there any way to get a proper preview without any specific hardware?
If not, what is the most budget friendly option?

hey, I know you asked about this a while ago but even though the Resolve manual says only the expensive Decklink cards work, I just got the cheap Decklink 4k mini monitor, and HDR preview works through HDMI.

[thirdmoon]

When trying to grade HDR in DaVinci, the preview looks washed out (I have a 4K HDR monitor).
Is there any way to get a proper preview without any specific hardware?
If not, what is the most budget friendly option?

hey, I know you asked about this a while ago, but even though the Resolve manual says only the expensive Decklink cards work, I just got the cheap Deck link 4k mini monitor, and HDR preview works through HDMI.

Yeah, I looked at some YouTube videos and found out later. I got one too. Thanks anyway.

[thirdmoon]

@RESET_9999
Is it okay to split and later merge DV mkv files. Does it cause any issues?

[RESET_9999]

@RESET_9999
Is it okay to split and later merge DV mkv files. Does it cause any issues?

I don't know, I never tried but if you don't remove any frames I guess it should be fine?
Sometimes I have to trim the start of a video and after, I always verify if my first frame still starts with a scene cut.

[RESET_9999]

Ok i think i figured out why positive trim offset is ignored in TV-LED HDMI source. That value is the ''lift'' control in Resolve and unlike slope(gamma?) and power(gain?) , offset(lift) metadata will raise black bars if higher than 0.025(2100 in 12bit pq) and if the device doesn't use L5. So this means HDMI source will have worse quality than TVs internal player but lift is rarely used higher than 0.005. The positive offset metadata is 100% ignored, even values under 0.025 have no effect.
It doesn't make sense that the metadata is not ignored in LLDV though and I just tested on my LLDV devices and it does indeed raise letterbox black levels. Fake TV-LED devices also don't ignore positive lift.

test file without L5: https://drive.google.com/file/d/1NgG1Zp ... drive_link
test file with L5: https://drive.google.com/file/d/18eNbkD ... drive_link

https://www.youtube.com/watch?v=AVZ7xcgeEAM



NO L5:



PROPER L5 on device that use it:

Lift/Gamma/Gain: These controls function similarly to the Y-only Lift, Gamma, and Gain master
wheels of the Color Wheels palette, to let you trim the overall contrast levels of the image. The
Dolby Best Practices Guide recommends to limit positive Lift to no more than 0.025, and mostly
restrict yourself to using Gamma and Gain if necessary to lighten the image.
— Saturation Gain: Lets you trim the saturation of the most highly saturated areas within a scene.
Lesser saturated values will be less affected.
— Chroma Weight: Darkens saturated parts of the image to preserve colorfulness in areas of
the image that are clipped by smaller gamuts that don’t have enough headroom for saturation
in the highlights.
— Tone Detail: Lets you preserve contrast detail in the highlights that might otherwise be lost when
the highlights are mapped to lower dynamic ranges, usually due to clipping. Increasing Tone
Detail Weight increases the amount of highlight detail that’s preserved. When used, can have the
effect of sharpening highlight detail.

You can use Gamma to elevate the blacks/shadows as required and use the Gain trim control to restore any highlights that may have been elevated or clipped.

For example, if a program were graded relative to a 4000 nit display, along with a single 100 nit
BT.709 trim pass, then a Dolby Vision-compatible television with 750 nit peak output will reference
the 100 nit trim pass metadata in order to come up with the best way of “splitting the difference” to
output the signal correctly. On the other hand, were the colorist to do three trim passes, the first
at 100 nits, -cond at 600 nits, and a third at 1000 nits, then a 750 nit-capable Dolby Vision television
would be able to use the 600 and 1000 nit trim metadata to output more accurately scaled color
volume and HDR-strength highlights, relative to the colorist’s adjustments, that take better advantage
of the 750 nit output of that television.

[Low Winter Sun]

Not so sure it's everything we want..

"Dolby Vision profile 5 and profile 8 both work. Profile 7 as used on Bluray discs, is currently converted on-the-fly by chosen mode by libdovi 209 due to a bug in the upstream proprietary code."
https://discourse.coreelec.org/t/coreel ... ion/20982

Just a heads up in case you haven't heard:
Our old and well hated friend the UGOOS AM6+ rises from the dead.

With the latest CoreELEC 20.3 Nexus version, it finally supports proper Dolby Vision FEL decoding with HD audio passthrough. I just installed it on my device (I have the AM6b+), configured audio passthrough, installed Plex Mod 4 Kodi and it just played every MKV Remux with Dolby Vision I tried. No Issues with pausing or skipping.

Source and how-to: https://www.reddit.com/r/PleX/comments/ ... _team_has/
Beware: My device did not boot from the SD card right away, I had to press the "recovery" button on the bottom of the device before powering it on. Then it booted fine - following start directly booted to CoreELEC, no need to press the recovery button again.

[ultrahorst]

Not so sure it's everything we want..

"Dolby Vision profile 5 and profile 8 both work. Profile 7 as used on Bluray discs, is currently converted on-the-fly by chosen mode by libdovi 209 due to a bug in the upstream proprietary code."

This is true for devices that are not the ugoos AM6 plus or the Minix counterpart. Look at the source code, the libdovi conversion is disabled by default in the amlogic-ng-dv device tree: https://github.com/CoreELEC/CoreELEC/bl ... r-Am.patch

[lexyz]

Ugoos AM6B+ with CoreELEC utilize FEL for sure.
Infamous Saving Private Ryan plays without flickering and with much-much less compression artifacts.
I would keep this device only for P7FEL mkvs

[RESET_9999]

please ask any further questions related to the dovi_scripts here: https://forum.doom9.org/showthread.php? ... ost1997616

thanks.

[jayper]

please ask any further questions related to the dovi_scripts here: https://forum.doom9.org/showthread.php? ... ost1997616

thanks.

I've created an account on Doom9 but I can't post there for 5 days. If you have a moment: if I wanted to create screenshots for a DV MEL title, is the best process to use: Mode S (7) and Workflow 1? Thanks very much!