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29th October 2015, 17:34 | #33961 | Link | ||
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Warner 306, Razoola and Asmodian thanks for the help! Problem solved. I discovered yesterday morning in the forum XBMC BRAZIL that could change the configs of madVR via KODI interface. I came here to be able to explain how and now saw the post Warner306 detailing the same procedure. Once again I thank the attention and elp of all! thank you. |
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29th October 2015, 22:17 | #33964 | Link |
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Can anyone comment on the usefulness of 10-bit output with current content? I have a 10-bit display but no 10-bit sources.
I am finding this topic confusing and would like some clarification. I am told the remapping of an 8-bit source to 10-bits will lead to an inaccurate color gamut and no gain in image quality.
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29th October 2015, 22:54 | #33965 | Link | |
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8 or 10-bit has nothing to do with the accuracy of the color gamut. The color gamut is calculated in 16-bit and dithered to 8 or 10 bit at a final output step. Actually more accuracy is lost going to 8-bit but this difference is extremely minor and not even measurable due to the dithering. If I did have a 10-bit display I would still use 8-bit output because I like using overlay more than FSE.
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29th October 2015, 23:47 | #33966 | Link | |
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http://www.soundandvision.com/conten...7bcb6kc7d2f.97 It claims TVs are currently incapable of display Rec. 2020. I thought 10-bit color and Rec. 2020 were one and the same, but it could be 10-bit output is only one of the specifications as stated by Wikipedia.
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29th October 2015, 23:53 | #33967 | Link |
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10-bit output and BT.2020 are not strictly related, although for BT.2020 to work properly, you need at least 10-bit. But you can have BT.709 and use 10-bit as well.
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30th October 2015, 07:23 | #33968 | Link | ||
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You could output to Rec. 2020's gamut using 8-bit (or 1-bit), the only reason 10-bit is required by the spec is because banding would be very bad with only 256 steps due to the huge dynamic range. Isn't even 10-bit insufficient to avoid banding with Rec. 2020's increased luma range and the specs suggest/require 12-bit for that?
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30th October 2015, 08:45 | #33969 | Link |
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As I understand it using 10bit with madVR as things currently stand means you do not have to use madVR's anti banding algorithms. Although my panel supports 10bit, my receiver does not so I have not investigated myself to be honest. Using 10 bit has nothing to do with the new colorspace spec (2020) currently in madVR.
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30th October 2015, 12:00 | #33970 | Link | |
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Using a 10-bit output means that dither is less visible. |
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30th October 2015, 12:34 | #33971 | Link |
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SDR bt 2020 should be fine with 8 bit too.
bt 709 kind of works with 7 and 6 bit too if dithered properly. so luma doesn't lose anything compared to bt 709 and PQ gamma should even help and make it better. and the chroma channel should survive with 8 bit too only green is a lot bigger. HDR BT 2020 is of cause a whole different story. |
30th October 2015, 12:40 | #33972 | Link |
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Not really, no. Full precision would require 12-bits even, and 10-bit dithered is probably going to be just fine. But 8-bit will easily band or require high dithering noise.
Unfortunately full testing will require much better screens than we have today. High-end screens can barely reach P3 color space, and are still far from full BT.2020 coverage. Not to mention that the BT.2020 specification calls for 10 or 12 bits.. HDR cannot really be compared directly, since it uses entirely different gamma curves, but HDR will definitely not work properly on lower bitdepth, thats for sure.
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LAV Filters - open source ffmpeg based media splitter and decoders Last edited by nevcairiel; 30th October 2015 at 12:47. |
30th October 2015, 13:15 | #33973 | Link |
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the 12 bit in bt 2020 comes from HDR.
with 100 CM² in mind the steps doesn't really increase in bt 2020 with 8 bit compared to 7 bit Bt 709. only green got a lot bigger about 100 % so 1 more bit is needed to get the same number of steps between each color. but blue and red are only ~5-15 % further away from the white point. so to get the same quality as 7 bit Bt 709 shouldn't be a problem with 8 bit. |
30th October 2015, 13:40 | #33974 | Link |
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There are people much smarter than you and me that clearly mandate 10-bit for BT.2020. You are free to use it in 8-bit if you want, but I certainly won't.
It is correct that BT.2020 strictly needs 1 more bit than BT.709, but arguably 8-bit was not quite enough for BT.709 either. Visual tests by experts have confirmed that 11-bit is needed to cover the full visual spectrum of BT.2020. But its all theoretical at this point still, consumer displays with such a high gamut are still far out. Hopefully next years TVs will at least get closer.
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LAV Filters - open source ffmpeg based media splitter and decoders Last edited by nevcairiel; 30th October 2015 at 13:45. |
30th October 2015, 19:07 | #33975 | Link | |
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30th October 2015, 19:54 | #33976 | Link |
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Is 4K bluray supposed to use Rec. 2020? I think so.
But what's the point if there is no display with that gamut. Plus, how would you make such a high gamut display and not make everything else that is standardized look like crap? Would need dynamic LUTs or something. Last edited by Arm3nian; 30th October 2015 at 20:11. |
30th October 2015, 19:58 | #33977 | Link |
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I don't think it works that way. The dithering needs to be done in the source itself, which is typically not the case (I'm guessing for compression efficiency reasons). If you play an undithered 8-bit file and add dithering in the rendering chain, it will make each 8-bit step more accurate, but it won't magically recover the missing steps from the source.
Last edited by e-t172; 30th October 2015 at 21:46. |
30th October 2015, 20:24 | #33978 | Link | |
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And since the new spectrum is larger, you can still show any old content within the new spectrum, and it'll look like it always did - assuming the renderer knows what its doing, and hopefully madVR does.
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LAV Filters - open source ffmpeg based media splitter and decoders Last edited by nevcairiel; 30th October 2015 at 20:48. |
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30th October 2015, 23:08 | #33979 | Link |
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I'm now clear on bit depths. Thanks for the discussion.
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31st October 2015, 04:48 | #33980 | Link | |
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madVR options explained Last edited by Asmodian; 31st October 2015 at 04:51. |
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direct compute, dithering, error diffusion, madvr, ngu, nnedi3, quality, renderer, scaling, uhd upscaling, upsampling |
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