Dolby Vision now possible through MP4 Mux.

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RESET_9999
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Joined: Mon Aug 05, 2019 7:12 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

No,
static DV metadata for a movie graded in the 1000-4000nits is not good and probably worse than static HDR10 because DV metadata is a lot more aggressive than HDR10 static curves.
For example if you have a 4000nits grade with a static 1000nits DV metadata. All the low-nits scenes will be darker and the brighter scenes will be more clipped than proper HDR10 metadata tone mapping curve. It's practically the same as making a DV P8 hybrid using two sources with different brightness, as shown here: https://www.youtube.com/watch?v=236athosits

Those movies with static DV are not done properly and should be avoided...
Trap is done properly because the content is below the DV 100nits floor (min)
staknhalo
Posts: 161
Joined: Sun Oct 11, 2020 12:05 am

Re: Dolby Vision now possible through MP4 Mux.

Post by staknhalo »

RESET_9999 wrote:
Tue Oct 29, 2024 3:55 pm
No,
static DV metadata for a movie graded in the 1000-4000nits is not good and probably worse than static HDR10 because DV metadata is a lot more aggressive than HDR10 static curves.
For example if you have a 4000nits grade with a static 1000nits DV metadata. All the low-nits scenes will be darker and the brighter scenes will be more clipped than proper HDR10 metadata tone mapping curve. It's practically the same as making a DV P8 hybrid using two sources with different brightness, as shown here: https://www.youtube.com/watch?v=236athosits

Those movies with static DV are not done properly and should be avoided...
Trap is done properly because the content is below the DV 100nits floor (min)
got it - so essentially as long as there's even just 'a little' data/grading in the L1 (as in native Trap and Longlegs) it's 'good' DV data - French Dredd still bad - thanks

Edit - I verify pre-aligned remuxes with the web source or different disc release just by quickly glancing at L1 which is why I wanted to be sure instead of aligning the web data to disc myself to be lazier lol :P
LV8HD
Posts: 37
Joined: Tue Jan 11, 2022 3:48 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by LV8HD »

@RESET_9999 in the most recent update you introduced the possibility to measure brightness of an HDR10 video on a frame-by-frame basis, which, to me, seems the most correct approach. Does this mean the MadVR method is less accurate even with excluded letterboxes? does it work on a scene-by-scene basis?
RESET_9999
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Joined: Mon Aug 05, 2019 7:12 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

LV8HD wrote:
Tue Oct 29, 2024 4:48 pm
@RESET_9999 in the most recent update you introduced the possibility to measure brightness of an HDR10 video on a frame-by-frame basis, which, to me, seems the most correct approach. Does this mean the MadVR method is less accurate even with excluded letterboxes? does it work on a scene-by-scene basis?
good catch haha. I didn't mention it in the release note because it's soooooo slow that it's unusable. I practically wasted my time on this code but it is indeed a frame by frame analysis / plotting. It uses the same script that generates the maxcll/fall stats in (7-2) (7-1).

Madvr analysis is also frame by frame but because I use Dovi_tool to plot the data, the graph is shot by shot. It's still 100% accurate but the values are rounded shot by shot. MadVR overall should be more accurate too since it measure pixels perceptually while the other script just measures the pixels as they are without any restriction.
kazuma
Posts: 162
Joined: Fri Nov 08, 2019 9:51 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by kazuma »

reset_9999, how did you find the PQ of the tenant with cm4.0?
RESET_9999
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Joined: Mon Aug 05, 2019 7:12 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

I dont know, never watched it. I dont like old movies.
LV8HD
Posts: 37
Joined: Tue Jan 11, 2022 3:48 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by LV8HD »

RESET_9999 wrote:
Tue Oct 29, 2024 5:10 pm
LV8HD wrote:
Tue Oct 29, 2024 4:48 pm
@RESET_9999 in the most recent update you introduced the possibility to measure brightness of an HDR10 video on a frame-by-frame basis, which, to me, seems the most correct approach. Does this mean the MadVR method is less accurate even with excluded letterboxes? does it work on a scene-by-scene basis?
good catch haha. I didn't mention it in the release note because it's soooooo slow that it's unusable. I practically wasted my time on this code but it is indeed a frame by frame analysis / plotting. It uses the same script that generates the maxcll/fall stats in (7-2) (7-1).

Madvr analysis is also frame by frame but because I use Dovi_tool to plot the data, the graph is shot by shot. It's still 100% accurate but the values are rounded shot by shot. MadVR overall should be more accurate too since it measure pixels perceptually while the other script just measures the pixels as they are without any restriction.
I see. Correct me if I'm wrong. MadVR measures pixels using perceptual quantization while the other script the raw data?
RESET_9999
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Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

right
LV8HD
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Re: Dolby Vision now possible through MP4 Mux.

Post by LV8HD »

@RESET_9999 pushed by curiosity I decided to check what the fastest method of measuring HDR with excluded letterboxes was on my PC (MKV measurement vs. Cropped ProRes measurement). The winner ended up being MKV although I have a good CPU (AMD Ryzen 7 7700x), but that's not the point.

As soon as both measurements were done (same movie) I took a look at them expecting to see the same results, however, they differed of a couple of nits. Why is that?

MKV measurement
Image

ProRes measurement
Image
RESET_9999
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Joined: Mon Aug 05, 2019 7:12 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

prores encode probably change the grain structure a little bit so small variation like that is normal

The winner ended up being MKV although I have a good CPU (AMD Ryzen 7 7700x), but that's not the point.
Thats surprising. On my i9 13900ks it's almost two times faster with prores.
daffie
Posts: 2
Joined: Sun Apr 16, 2023 6:10 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by daffie »

kazuma wrote:
Thu Oct 31, 2024 5:17 pm
reset_9999, how did you find the PQ of the tenant with cm4.0?
Hi, how do you watch ''with cm4.0'' ?
By using the CPM build with the AM6B+ ?
TheEqualizer
Posts: 50
Joined: Tue Feb 21, 2023 3:50 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by TheEqualizer »

RESET_9999 wrote:
Wed Oct 16, 2024 7:28 pm
maybe, I dont know. You can also demux with tsmuxer
I've done all sorts of tests with this German edition of the movie "Late Night with the Devil". I used mkvtoolnix, dovi_script, DGDemux, MakeMKV, the first three have a similar output, the last one does not output correctly, but if you compare the scene-cuts of all the options, but they do not match the scene-cuts of the EL layer extracted using tsMuxeR, does this mean that technically remux mkv 7Profile is not allowed?

EL_scene-cuts

MKVToolNix_DoVi-Script_DGDemux_scene-cuts

https://i.ibb.co/KrX9cbG/EL-PLOT.png
https://i.ibb.co/VBs1t5h/ST-DL-PLOT.png
RESET_9999
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Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

I dont know. I watched this one in Profile 8 without EL and everything was fine.
TheEqualizer
Posts: 50
Joined: Tue Feb 21, 2023 3:50 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by TheEqualizer »

RESET_9999 wrote:
Wed Nov 06, 2024 12:52 am
I dont know. I watched this one in Profile 8 without EL and everything was fine.
I'll tell you more, those who have already watched the remux in mkv 7p also did not see anything suspicious, so in the question I pointed out that technically it is still not correct and it is not allowed to make such remuxs. Perhaps if a British UHD appears, things will be better on it.
RESET_9999
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Joined: Mon Aug 05, 2019 7:12 pm

Re: Dolby Vision now possible through MP4 Mux.

Post by RESET_9999 »

i dont know but my p8 remux is perfectly in sync with the BL scene cuts
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