Hi guys. Amazing thread. After trying to read all of it I got a few questions in my head. My setup is Shield 2019 Pro + several LG OLEDs in my family (C9, BX etc).
1.) I deleted the question as you can not make Profile 8 BL+EL+RPU copy of Profile 7 BL+EL+RPU as there is no EL in Profile 8. My mistake
2.) I do also for some movies 2160p UHD Rips (re-encodes) x265 CRF 17 preset slower. I am able to watch them on 4K TVs around the globe whenever I travel and I want to play a movie as very often 20-40 Mbit connection is no problem in a modern hotele whereas 50-90 Mbit for remuxes is too much in 99% cases in public places. Now the question is. I am able to extract FEL or MEL layer and extract RPU. Usually I attach RPU layer to my 2160p re-encodes and it plays as Dolby Vision video (without EL layer) without a problem or any glitches. However I was thinking about adding EL track as well? I rather don't see a point in this as the goal to re-encode is to reduce the size and quality for lower bitrate (storage does not matter much for me) and then if I go from 60 GB to 25 GB what would be the point in increasing the size by 4-8 GB back only to get 12 bit video on something I anyway just reduced the quality already. Do you have any thoughts on this? So I rather just keep RPU only with 2160p re-encodes.
3.) How about MEL? If the EL layer is MEL. Does it make sense to add it? After reading this thread I understand MEL would not bring any value as well in my case (point 2)?
4.) One thing I don't understand. I join with dovi_tool original EL layer (for example 8 GB) with original RPU (upgraded to dvhe
. Then I mux it with mkvtoolnix with the re-encoded 2160p BL layer (let's say 25 GB). Then i have a mkv file with 2 HEVC tracks (25+8 = 33 GB mkv at this point). Then I go to MakeMKV, open it and save as MKV. I receive single layer dual track profile 8 Dolby Vision file. It plays correctly. But why total size of this file is around 29 GB and not 33 GB?
5.) Last but not least. A bit crazy question. Anyone has been playing with re-encoding FEL layer? I did some tests. For "Anna" I re-encoded 8 GB FEL layer to ca 1 GB (x265 17 slower). But for "Bravehart" it went from 8 GB to 13 GB (x265 17 slower). When I remux it and create dovi profile 7 compliant mkv it plays correctly on Shield as DoVI. To be honest I'm a bit curious what in fact I have created? 12 bit re-encoded file? How is the re-encoded BL matching the re-encoded FEL? During re-encdoding for sure the original BL:FEL won't match the re-encoded BL:FEL in terms of pixel-to-pixel match.
Anyway it works, it plays well on Shield. For movies like "Anna" increasing the 25 GB 2160p re-encode with 1GB re-encoded FEL is not a big deal. But for movies like "Braveheart" I would have to add 25 BL re-encode, the 8 GB original FEL. Anyway after MKV the "Braveheart" 2160p re-encode BL+EL(original)+RPU is not 33 GB but 29 GB (so plus 4GB) which, on the other hand, is not so bad after all (+13%).
Anyway the question is - does it make much sense? To be honest I can not see the difference on my LG OLED between re-encoded BL + RPU vs re-encoded BL + re-encoded EL + RPU vs re-encoded BL + original EL + RPU. Maybe someone else is more patient in this matter and can tell the difference?
And just to let you know in case anyone wondered. Yes, you can attach DoVi to 720p HEVC HDR re-ecodes. After merging with RPU it plays as 720p Dolby Vision. The quality is actually really nice on LG OLED for 3-4 MB/s 720p DoVi files. It really looks god
Yes, you can also re-encode FEL layer to 720p HEVC track. For example "Anna" FEL is reducing its size from 8 GB to 300 MB. For "Braveheart" it went down from 8 GB to 4 GB.
In the end you can mux it into 720p DoVi BL (re-encoded) + EL (re-encoded) + RPU and it also plays well
Regarding the file size. MKVtoolnix size is 5,7 GB for re-encoded BL + 4,5 GB for re-encoded EL which is 10,3 GB. However final MakeMKV Profile 7 file for 720p DoVi BL (re-encoded) + EL (re-encoded) + RPU is 7,9 GB in case anyone wondered.
So with movies like "Braveheart" it does not make sens or one would have to use more aggressive EL endcoding like CRF21/22? (then: how for example CRF21/22 EL will impact the BL+EL quliaty vs pure BL CRF17 - this might be interesting).
But with movies like "Anna" you could keep very low size files for DolbyVIsion comedies in 720p or 1080p - like for example "Spaceballs". For 5-8 GB you can have full BL+EL+RPU Dolby Vision comedy with "enough" quality for this kind of movie.