tango306 wrote: ↑
Tue May 28, 2019 3:02 am
sm0ke83 wrote: ↑
Fri May 24, 2019 11:16 am
Read your discussion with Grencola...
I'm having trouble creating good mp4 from mkv. Been reading on this forum for that and it's hard ignore the discussion
...I was wondering why u think original UHD Dolby Vision Blu-ray discs are 12-bit? Or did I misunderstood?
A few months ago (when DV profiles was being discussed) I found this pdf from Dolby Laboratories, maybe u find this interesting:
https://www.dolby.com/us/en/technologie ... levels.pdf
Nowhere in this file is 12-bit mentioned... Look at table 1 at page 9, only 10-bit HEVC is being used in DV profiles.
You are not missing anything. In fact, you're right. I've been searching and digging for the last couple of days. Thanks for the link.
A few facts I've found and learned.
1. 4K UHD Blurays use H.265 HEVC Main 10 profile. H.265 HEVC Main 10 supports up to 10-bit. (No 12-bit support)
2. On 4K UHD Bluray disc supporting Dolby Vision, both base layer and DV enhancement layer are encoded in H.265 HEVC Main 10. This basically means they all are 10-bit.
3. Dolby Vision Profile 7 (dual layer) is used in 4K UHD Bluray and Dolby Vision Profile 5 (single layer) is used for iTunes and Netflix 4K streaming.
4. Dolby Vision may supports up to 12-bit color depth and 10,000 nits of peak luminance. However, this "up to" specifications are to future proof their tech. Currently, all DV supported media in consumer market are in 10-bit color depth.
Dolby Labs own DV demo files are encoded in H.265 HEVC Main 10 and are in fact in 10-bit color depth.
5. What Oppo-203 player is doing when 4K UHD Dolby Vision disc is played is padding 10-bit into 12-bit container. I guess this mislead-ed many people (including myself). And lots of 4K Bluray title review sites stating Dolby Vision Bluray titles having 12-bit color are flat out misinformed.
I am quoting myself to correct misinformation.
Grencola and sm0ke83,
After I posted above, I kept on reading about Dolby Vision. And learned that it actually is 12-bit
At the encoder stage level, the 12-bit Dolby Vision signal is splitted into a base layer and an enhancement layer. At the decoder stage level, the 12-bit Dolby Vision is recombined. Dolby has patented this. https://patents.google.com/patent/US20140050271
That's how Dolby Vision Profile 7 (dual layer) works to split and re-combine 12-bit color data.
Contrary to dual layer DV Profile 7 on 4K UHD Blu-ray discs, streaming services such as iTunes and Netflix who are based on DV Profile 5 (single layer) are in fact in 10-bit color depth.
My first post in this thread started with a question. It was this comment/post in reddit. https://www.reddit.com/r/Piracy/comment ... dium=web2x
Oppo-203 reporting 10-bit video output (instead of 12-bit) when muxed MP4 DV file is played.
This is not to say that there's something wrong muxed MP4's DV stream. I think Dolby Vision either works or doesn't work. It may be Oppo 203 player reporting false info when reading (and outputting) dual layer DV streams from MP4 container. More investigation is needed.