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10th October 2017, 14:18 | #1 | Link |
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How to detect Dolby Vision in a videofile?
Ladies and gentlemen,
the issue at hand is about Dolby Vision Does anyone have an idea how to detect DV in a videofile? For example MediaInfo doesnt seem to have the appropriate info whether DV is in the file or not. For example this TS Dolby Vision file right here: https://drive.google.com/uc?export=d...0RDWVVsWUtRMnM Dolby Vision works. Tested on an LG Oled with DV capability. After throwing the TS file in MKVToolNix the MediaInfo is quite similar however DV doesnt work anymore on my tv, its gone or deactivated or whatever. The metadata seems to get lost. So is there a way to see DV in the TS file to see the difference between the TS and the mkvtoolnix mkv? Thank you very much in advance I know DV is still very new and in the early stages more or less. But maybe some of you have an idea for the issue at hand Waiting for PowerDVD for example is possible of course but it will take months I suppose... Last edited by d3rd3vil; 10th October 2017 at 14:23. |
14th October 2017, 00:05 | #3 | Link |
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As far as I know DV data is inside h265 headers and it's dynamically inserted per scene. It's quite complicated and you can look at x265 documentation to see how it's done. There is some section about it.
update: sorry, I was talking about HDR10+, but DV is about the same. Last edited by kolak; 14th October 2017 at 13:34. |
14th October 2017, 18:36 | #6 | Link |
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https://www.dolby.com/us/en/technolo...hite-paper.pdf
Yep, from the looks of this, they really want to lock it down. Gonna require a secret decoder ring, er chip, no doubt... |
14th October 2017, 23:29 | #7 | Link |
Derek Prestegard IRL
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This dual stream technique is not used in practice AFAIK.
Real Dolby Vision implementations (I forget the profile numbers) for OTT VOD are pure 10 bit HEVC with proprietary dynamic metadata stored in SEI messages. |
15th October 2017, 07:31 | #8 | Link |
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On Blu-ray it is.
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20th October 2017, 18:29 | #9 | Link |
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Correct. Although I don't know that it is actually required for discs.
And I have heard at least one streaming provider is currently using dual layer. The single layer is quite a bit more bitrate efficient, so the general trend is to use that instead, But dual layer was available a lot earlier, so that's what a lot of early tooling was built around. |
20th October 2017, 18:36 | #10 | Link | |
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Quote:
The single layer Dolby Vision uses a non-backwards compatible HEVC 10-bit base layer, using ICtCp and dynamically adjusting so that the 10 bits of precision are mapped to the current video parameters to preserve more precision. The file is absolutely not playable in a general HEVC player; it needs a lot of metadata-driven Dolby algorithms to convert from the non-backwards compatible stream to Dolby's 12-bit ICtCp space, and then using other metadata to go from that to the display, optimizing for the display's characteristics. HDR10+ is a HDR-10 base layer, plus metadata in the SEI that can be used to improve tone mapping, or ignored. So those streams are playable in themselves in any HDR-10 capable player. Dolby has a big proprietary display tone mapping library. HDR10+ is really just the descriptive metadata; it's up to each vendor to figure out how to use that metadata in their own tone mappers. |
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20th October 2017, 21:09 | #11 | Link |
Life's clearer in 4K UHD
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Well....
When my Oppo UDP-203 plays typical HDR video sources, the player produces the following info: - Media Information HDR Format: BDMV HDR Colour space: BT2020 YCbCr 4:2:0 @ 10-bit HDMI(Main) Output Information HDR Format: HDR Colour Space: BT2020 YCbCr 4:2:2 @ 12-bit But when playing Dolby Vision sources, my Oppo produces the following info: - Media Information HDR Format: Dolby Vision Colour space: Dolby Vision @ 12-bit HDMI(Main) Output Information HDR Format: Dolby Vision Colour Space: Dolby Vision @ 12-bit So somehow a 4:2:0 10-bit (not 12-bit) encoded video stream becomes a uniquely flagged 'Dolby Vision' 12-bit output...
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Last edited by SeeMoreDigital; 21st October 2017 at 22:42. |
21st October 2017, 10:31 | #12 | Link |
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Well there are 2 things that could be interesting.
1: A software mediaplayer that can play DV material. That will probably be tricky. 2. A way to convert all the relevant data to mkvs or ts formats so the TV can handle the rest and play it. And the second option should be easier to accomplish?! Of course there are already ts DV files that are no prob for the tv. Last edited by d3rd3vil; 21st October 2017 at 10:35. |
22nd October 2017, 16:48 | #13 | Link | |
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Quote:
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22nd October 2017, 18:22 | #14 | Link |
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I wonder if it's possible to find some 'repeat information' with a hex editor...
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2nd November 2017, 16:13 | #16 | Link |
Life's clearer in 4K UHD
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Jeez... There's less than two dozen UHD discs currently available (and most of them arn't worth watching). What's the rush?
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