Dolby Vision now possible through MP4 Mux.

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paul8
Posts: 1
Joined: Wed Feb 05, 2025 5:16 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by paul8 »

How can I know if a FEL has been properly baked into the BL?

I have two DV 8.1 files of the movie Wind River. Both encoders team are supposed to perform FEL Baking, but there's a difference between these two files that makes me doubt it.

The difference lies in the BL MDL value: 1000 nits for one, 4000 nits for the other. If a FEL is baked into the BL with an MDL RPU of 4000 nits, the BL MDL should also become 4000 nits, right? Or am I wrong ?

Image

Image

Thanks for your help !
Last edited by paul8 on Sat Feb 08, 2025 11:46 pm, edited 1 time in total.
coopzr
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Re: Dolby Vision now possible through MP4 Mux.

Post by coopzr »

Hey @RESET_9999, some questions for you.

1. Does HDR10+ have manual artistic trim capabilities equivalent to DV? For example, I understand that cmv2.9 L2 trims and cmv4.0 L8 trims are 100% manually generated. Do colourists even have this capability in HDR10+? If yes, are these manual artistic trims lost when converting HDR10+ to DV?

2. In the case of generating dynamic DV from a static source, why is it that we should ignore the 'mastering display color primaries' and 'mastering display luminance' from the mediainfo and instead measure the hdr brightness to determine if maxcll is >10%? Is it simply the case that the mediainfo is incorrect or is this an artistic decision?

3. I have a very new LG OLED (C4) and the L5 black bars only slightly dim my screen instead of making them black (as is the case with most OLED's I believe). I rarely watch movies with subtitles and even if I did, the slight dimming is fine and doesn't affect my viewing experience. Should I set dolby_vision_keep_source_meta_level_5 to 0, 1 or 2?

I appreciate everything you do for the community and the many hours you have spent sharing your knowledge :)
RESET_9999
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Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

coopzr wrote:
Fri Feb 07, 2025 12:55 pm
Hey @RESET_9999, some questions for you.

1. Does HDR10+ have manual artistic trim capabilities equivalent to DV? For example, I understand that cmv2.9 L2 trims and cmv4.0 L8 trims are 100% manually generated. Do colourists even have this capability in HDR10+? If yes, are these manual artistic trims lost when converting HDR10+ to DV?

2. In the case of generating dynamic DV from a static source, why is it that we should ignore the 'mastering display color primaries' and 'mastering display luminance' from the mediainfo and instead measure the hdr brightness to determine if maxcll is >10%? Is it simply the case that the mediainfo is incorrect or is this an artistic decision?

3. I have a very new LG OLED (C4) and the L5 black bars only slightly dim my screen instead of making them black (as is the case with most OLED's I believe). I rarely watch movies with subtitles and even if I did, the slight dimming is fine and doesn't affect my viewing experience. Should I set dolby_vision_keep_source_meta_level_5 to 0, 1 or 2?

I appreciate everything you do for the community and the many hours you have spent sharing your knowledge :)
1. No and AFAIK, HDR10plus is fully automated and not editable.
2. static tone mapping is used on top of the dynamic metadata in DV. A 4000nits MDL looks much darker than a 1000nits MDL with the same dynamic metadata. Also, with a 4000nits MDL, Level 1 starts dimming with lower values. It starts at 400nits on my C2 while with the 1000nits MDL, it starts dimming only at 850nits.
3. I leave L5 active on my C2 since the semi-transparent mask doesn't bother me as well. So I use ''1''
Sorry for my English.
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coopzr
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Re: Dolby Vision now possible through MP4 Mux.

Post by coopzr »

RESET_9999 wrote:
Fri Feb 07, 2025 3:11 pm
2. static tone mapping is used on top of the dynamic metadata in DV. A 4000nits MDL looks much darker than a 1000nits MDL with the same dynamic metadata. Also, with a 4000nits MDL, Level 1 starts dimming with lower values. It starts at 400nits on my C2 while with the 1000nits MDL, it starts dimming only at 850nits.
I think I understand what you are saying. However, can you please elaborate on my question? Is mediainfo simply wrong sometimes or is there a technical reason that 'mastering display color primaries' and 'mastering display luminance' should be ignored?
RESET_9999
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Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

Is mediainfo simply wrong sometimes
mediainfo is ok and there's nothing wrong in grading 200nits (for example) on a 4000 monitor. You can use the original MDL if you doubt my reason, it's fine.
is there a technical reason that 'mastering display color primaries' and 'mastering display luminance' should be ignored?
No other reason than the one I already told you.
A 4000nits MDL looks much darker than a 1000nits MDL with the same dynamic metadata
Sorry for my English.
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darrrkmanxxx
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Re: Dolby Vision now possible through MP4 Mux.

Post by darrrkmanxxx »

Hey guys,

at which step davinci rersolve does a bad job with hevc?

Scene detection or the analyzing itself?
RESET_9999
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Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

both
Sorry for my English.
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nekno
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Re: Dolby Vision now possible through MP4 Mux.

Post by nekno »

darrrkmanxxx wrote:
Sat Feb 08, 2025 11:31 am
Hey guys,

at which step davinci rersolve does a bad job with hevc?

Scene detection or the analyzing itself?
IME, it isn't the scene detection or CM analysis, per se, it's that the frames are decoded inaccurately from the start, so bad data is fed to both algorithms, making both inaccurate as a result. Garbage in, garbage out.

In my testing, the HEVC decoding in Resolve was inserting additional frames, so as a result the scene starts and durations were all inaccurate, not because the scene detection algo is bad, but because (as you can see when scrubbing through the video) the scenes actually do start and end at inaccurate frames. And the DV CM algo is based on scenes and frames, so if it doesn't get accurate data, it's going to start and stop scenes at inaccurate times.

For example ---

3 actual scenes:
(1) Start frame: 0, Duration: 100; (2) Start frame: 100, Duration: 100; (3) Start frame: 200, Duration: 100

Resolve-decoded HEVC:
(1) Start frame: 0, Duration: 101; (2) Start frame: 101, Duration: 103; (3) Start frame: 204, Duration: 100

So all the scenes in the DV metadata start sliding later by a couple/few frames each time another frame decoding error is introduced (in scenes 1 & 2).
darrrkmanxxx
Posts: 93
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Re: Dolby Vision now possible through MP4 Mux.

Post by darrrkmanxxx »

nekno wrote:
Sun Feb 09, 2025 9:07 am
darrrkmanxxx wrote:
Sat Feb 08, 2025 11:31 am
Hey guys,

at which step davinci rersolve does a bad job with hevc?

Scene detection or the analyzing itself?
IME, it isn't the scene detection or CM analysis, per se, it's that the frames are decoded inaccurately from the start, so bad data is fed to both algorithms, making both inaccurate as a result. Garbage in, garbage out.

In my testing, the HEVC decoding in Resolve was inserting additional frames, so as a result the scene starts and durations were all inaccurate, not because the scene detection algo is bad, but because (as you can see when scrubbing through the video) the scenes actually do start and end at inaccurate frames. And the DV CM algo is based on scenes and frames, so if it doesn't get accurate data, it's going to start and stop scenes at inaccurate times.

For example ---

3 actual scenes:
(1) Start frame: 0, Duration: 100; (2) Start frame: 100, Duration: 100; (3) Start frame: 200, Duration: 100

Resolve-decoded HEVC:
(1) Start frame: 0, Duration: 101; (2) Start frame: 101, Duration: 103; (3) Start frame: 204, Duration: 100

So all the scenes in the DV metadata start sliding later by a couple/few frames each time another frame decoding error is introduced (in scenes 1 & 2).
got it. I really appreciate your explanation.
Honestly I'm getting exactly the same behavior with Prores422 on macos in resolve when I let it do it the background while working with other apps.
I have radeon 6900 xt 16gb vram as gpu.
Resolve only does it's job when I leave the computer completely untouched. So resolve is very unreliable in that way.
darrrkmanxxx
Posts: 93
Joined: Mon Apr 13, 2020 9:55 am

Re: Dolby Vision now possible through MP4 Mux.

Post by darrrkmanxxx »

Is there any release group that does proper fel baked hdr12 remuxes?
RESET_9999
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Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

Baking FEL requires re-encoding so what you're asking is not possible.
An untouched FEL remux can only be played properly on a device that can decode it.

Just get the Ugoos if you want the best quality without compromise.
Sorry for my English.
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nekno
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Re: Dolby Vision now possible through MP4 Mux.

Post by nekno »

darrrkmanxxx wrote:
Sun Feb 09, 2025 3:21 pm
Honestly I'm getting exactly the same behavior with Prores422 on macos in resolve when I let it do it the background while working with other apps.
Resolve only does it's job when I leave the computer completely untouched. So resolve is very unreliable in that way.
That's odd. Once transcoding to ProRes I haven't had any issues with Resolve on Windows or macOS, but can't say whether I specifically foregrounded another app. I definitely did while transcoding with FFMPEG, but that's it.
valington
Posts: 44
Joined: Tue May 02, 2023 1:39 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by valington »

RESET_9999 wrote:
Mon Feb 10, 2025 6:23 pm
Baking FEL requires re-encoding so what you're asking is not possible.
An untouched FEL remux can only be played properly on a device that can decode it.

Just get the Ugoos if you want the best quality without compromise.
Reset which workflow for container mkv p5 profile dolby vision to make container mp4 p5 profile dolby vision
RESET_9999
Posts: 2411
Joined: Mon Aug 05, 2019 7:12 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

all the workflows are explained on the github or doom9 website...

https://forum.doom9.org/showthread.php?t=185317
MODE.B (5) =
BATCH MUXER

Can batch mux any DV source to TS or MP4
MKV/MP4 to TS
MKV/TS to MP4
Sorry for my English.
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powdeau
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Re: Dolby Vision now possible through MP4 Mux.

Post by powdeau »

If a video has this static metadata,
Image
would it be more accurate to watch it on G4 in HDR10
Image
or in generated DV?
Image
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