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test-full-band / tfb-video

Generator of test video files for testing your media playback devices and calibrate TV sets
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Request for a Dolby vision pluge pattern #4

Open kryptonite5 opened 5 years ago

kryptonite5 commented 5 years ago

Request for a Dolby vision pluge pattern to set correct black level on LG OLED TVs. I personally own a LG C8 and have found your SDR and HDR pluge patterns to be incredibly useful.

In the future, if you could also help include some patterns in SDR, HDR and Dolby vision - for white clipping (0-1000 nits & 1000-4000 nits) and colour clipping (0-1000 nits & 1000-4000 nits), that would be even more awesome.

Thanks.

igorzep commented 5 years ago

I've added Black PLUGE pattern in DV to the experimental downloads section, so you can download it here. Let me know if it works well and on what TV set / media player.

As you might have seen in the sources the full list of patterns the project has is almost ready in DV for quite some time, but unfortunately I've had no enough time to do some final checks and adjustments. Hopefully I will find it sooner than later.

Concerning the white clipping - it is an interesting problem on what those patterns should be. I definitely have those patterns in mind (for all the SDR/HDR/DV sets) but dynamic metadata adds a new dimension to them. What actually would you want to test with them in DV? Is it that DV correctly maps all light range of the scene to the TV capabilities given the metadata correctly presented? Is it finding the point where it actually clips given the metadata is at the TV capabilities or below them? For HDR it is also an interesting problem (that would logically only depend on Max Content Light Level meta, but in practice sometimes depend on Mastering Display Max Luminance meta)...

For SDR it is simple - you are just finding at what code point it clips. For HDR/DV I would like to be discussed what patterns do we really need (re. Mastering Monitor meta, HDR10 Content (global) meta and DV Content (per frame) meta).

kryptonite5 commented 5 years ago

Hi Igor,

Thank you very much for the DV pluge pattern. I have had a major issue with blacks on my LG C8, and your pattern exposed it instantly!

Some background:

I live in India, and don't have access to any professional calibrators nearby, so the best I can do (without spending a bomb on calman + equipment) is to use test patterns and make basic settings to the panels I use.

For SDR: I've relied on the black level, white/contrast level, and color clipping patterns from here: https://www.avsforum.com/forum/139-display-calibration/948496-avs-hd-709-blu-ray-mp4-calibration.html I adjust brightness till I can see bars 17 and above glow (black clipping pattern), and not clip earlier I adjust contrast till i can see bars up to 234 glow (white clipping pattern), and not clip earlier I also adjust colour till I see all the 3 primary RGB colors glow till 234 (color clipping pattern), and not clip earlier

For HDR: I've relied on the black level, white & color clipping patterns from here: https://drive.google.com/drive/folders/1UnPiHQrJjldIPbfVwt95S7ck0tvR4yUM https://drive.google.com/drive/folders/17z94AGSQN7m0VLS1oDEkViQlr0wvpWhG I adjust brightness till I can see bars 68 and above glow (black level patterns), and not clip earlier I adjust contrast till i can see my TV tone map correctly to 1000 nits (white 240-1000 nits pattern), and not clip earlier I also adjust color till I see all my TV tone map all colors correctly up to 1000 nits (01. 240-1000 nits pattern), and not clip earlier

For Dolby vision, however, I had no access to any such patterns, till I came across your thread.

Now onto why your patterns interested me the most: My LG C8 is notoriously bad at handling dark greys or near black regions, irrespective of SDR, HDR or Dolby Vision I constantly see garbage, macroblocking, what they now call near-black-chrominance-overshoot, etc, so I've been on a quest to sort this out.

Your SDR and HDR pluge patterns gave me the biggest break at some amount of relief from this TV. What I ended up doing with your pluge patterns is eliminated the TV from displaying the first visible grey bar (from the left) out of 2 grey bars that are mandatory to be displayed.

So for SDR, by eliminating the first grey bar using your pluge pattern, in the Technicolor preset, I went from from an ideal world (no black crush) Brightness = 50, Contrast = 85, to Brightness = 48, Contrast = 85. This resulted in clipping the black bars 17 & 18 (19 and above glow) in the AVS pattern.

For HDR, by eliminating the first grey bar using your pluge pattern, in the Technicolor preset, I went from an ideal world (no black crush) Brightness = 50, Contrast = 100, to Brightness = 50, Contrast = 97 What's interesting here is a brightness of 49 resulted in both grey bars being crushed, but keeping a brightness of 50 and reducing contrast to 97 did the job. This resulted in clipping the black bars 68 & 72 (76 and above glow) in Mehanik's patterns.

Now, people may argue that I'm crushing black, but honestly, I'm so tired of seeing garbage on the TV in dark scenes, that this compromise is absolutely perfect. And I don't think the black crush is much to be honest, I continue to see good shadow detail in the dark. I pretty much fixed my SDR and HDR issues. After these settings, I never ever saw garbage or bad-near-black-level handling in any situation SDR or HDR content again.

But I continued to see garbage in Dolby vision, and the garbage in Dolby vision is so bad, that I cannot even explain it accurately. Most times, in dark scenes in Dolby vision, the entire screen fills with what feels like a constant moving wave pattern that looks like snow+dirt mixed, from the right bottom of the TV, to the top left. This ridiculous pattern is even constantly visible when you pause the content!

While I wanted to apply the same HDR settings blindly to DV, I also wished for a pluge pattern to ensure I was doing the right thing. And that's when I requested for such a pattern from you, and your pattern instant showed that constant moving wave pattern of snow+dirt, confined exactly within the first grey bar of your DV pluge pattern. I tried to take videos of this with multiple phones, but the image is already so dark, that no phone (that I have access to) is able to capture this correctly.

For DV, I was able to eliminate the first grey bar and yet display the second grey bar by using a brightness of 49, contrast = 100. This was unlike HDR, where brightness 49 crushed both black bars. But, believe it or not, the ugly moving wave pattern of snow+dirt moved to the second grey bar as soon as I eliminated the first grey bar with a brightness of 49. After playing around a bit, I found that these settings eliminated the first grey bar, yet also ensured the ugly moving pattern does not move to the next bar. In Cinema Home preset, brightness = 49, contrast = 99 In Cinema preset, brightness = 50, contrast = 97

Hope this helps answer your questions, and thank you again for all the hard work.

Cheers, Vivek

On Wed, Feb 13, 2019 at 9:52 PM Igor Malinin notifications@github.com wrote:

I've added Black PLUGE pattern in DV to the experimental downloads section, so you can download it here https://github.com/testing-av/testing-video/releases/download/v0.0.1-alpha/BlackPLUGE.U4K_DVp5.mp4. Let me know if it works well and on what TV set / media player.

As you might have seen in the sources the full list of patterns the project has is almost ready in DV for quite some time, but unfortunately I've had no enough time to do some final checks and adjustments. Hopefully I will find it sooner than later.

Concerning the white clipping - it is an interesting problem on what those patterns should be. I definitely have those patterns in mind (for all the SDR/HDR/DV sets) but dynamic metadata adds a new dimension to them. What actually would you want to test with them in DV? Is it that DV correctly maps all light range of the scene to the TV capabilities given the metadata correctly presented? Is it finding the point where it actually clips given the metadata is at the TV capabilities or below them? For HDR it is also an interesting problem (that would logically only depend on Max Content Light Level meta, but in practice sometimes depend on Mastering Display Max Luminance meta)...

For SDR it is simple - you are just finding at what code point it clips. For HDR/DV I would like to be discussed what patterns do we really need (re. Mastering Monitor meta, HDR10 Content (global) meta and DV Content (per frame) meta).

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