Please help to edify ProspectorPete on RGB ranges and proper video setups *spinoff of spinoff*

Discussion in 'General Discussion' started by ProspectorPete, Mar 24, 2017.

  1. ProspectorPete

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    Cinema had never had true black btw. Movies are not designed with that in mind right?
    A 21:9 blu-ray always has black bars that are blacker than even the blackest detail in the movie.
    Come to think of it, no BD ever mastered has true black levels, correct?
     
  2. Shifty Geezer

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    Cinema is crap picture quality. Movies are captured at whatever the photographic medium can catch, and yes, they do want pitch black in very dark scenes - the minimum brightness captured in footage when encoded is zero (or 16 in limited RGB), and cinematic lighting isn't used to ensure the minimum brightness is 25% just to accommodate appalling projector light bleed. That's why many dark movies are impossible to see anything because they lose contrast at the bottom end. OLED and pure black is better than cinema.
    Your TV isn't set up right. ;)
    Using a test pattern, you'll either have black set at 0 or 16 depending on whether you are using full RGB or limited RGB. But where most (all?) encodes are limited RGB, your TV should show a brightness level of 16 as pure black.

    In short, movies like everything else (photos, games) should have a zero-level brightness presented as zero light. Any medium that cannot achieve that is inadequate. We simply make do because there aren't better alternatives.
     
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  3. ProspectorPete

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    Explain it then; how can the outside border of a blue ray be blacker Tham the darkest black of space in Alien, gravity, interstellar, and so on? Has space never been intended by Oscar winning directors?
     
  4. goonergaz

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    Because your TV is too bright, you need to check your contrast and brightness levels.

    http://electronics.howstuffworks.com/how-to-hdtv2.htm
     
  5. Shifty Geezer

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    You need to calibrate your TV so the black levels in a black video are as dark as the TV can do, as dark as the border.
     
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  6. ProspectorPete

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    In the SOURCE blu ray there should not be a difference; this is when viewed on a color calibrated macbook
    edit: using "Digital Color Meter" there are some 0:0:0 blacks in Gravity, though I did not check the screengrab
     
  7. Shifty Geezer

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    What's the SOURCE blu ray? Is your colour calibrated Macbook playing the video in full RGB mode while the video itself is limited RGB?
     
  8. ProspectorPete

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    This is what I meant, although it's a different movie and not a direct screen grab, compare the 'blacks'
    [​IMG]

    Edit: on the 2016 LG 6-something this showed as no visible difference black difference between the 'pal borders' and the rest of the image, at different settings, which (o)led me to believe that the LG was employing black crush for 'true' blacks

    same with:
    [​IMG]

    edit: interstaller also doesn't have 0:0:0 black in space
     
    #8 ProspectorPete, Mar 24, 2017
    Last edited: Mar 24, 2017
  9. BRiT

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    Your TV isn't properly calibrated.
     
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  10. ProspectorPete

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    if your tv doesn't show a difference between the border black and the inside frame black then your tv is broken, or an (early generation-2016) OLED
    [​IMG]
     
  11. BRiT

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    No, YOU dont have your setup properly calibrated. You should have multiple calibration settings for different source materials. Just because you have issues dont infer that other prosumers have issues.
     
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  12. ProspectorPete

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    Okay, sorry then my mistake, I will have both my tv and my macbook repaired (under warranty hopefully), thanks for the advise!
     
  13. ProspectorPete

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    The issue with -2016 OLED is that it can't reliably produce near-black without getting visual artefacts. You don't have to believe me, but LG said they fixed it for 2017 models, but maybe LG was just lying, and there never was any problem. So they are lying because there was nothing to be fixed in the first place!
     
  14. goonergaz

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    If you link to LG talking about the issue then that would help clear up things. Firstly though, you said Bluray couldn't do true black, which is completely incorrect.
     
  15. ProspectorPete

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    my statement:
    "A 21:9 blu-ray always has black bars that are blacker than even the blackest detail in the movie."

    -a blu ray is saved as (16:9) 1920*1080

    -a 21:9 movie has about 800 vertical lines, out of the 1920*1080 blu-ray only 1920*800 is actually pixels from the movie, the rest is black

    -the black is defined as r:0 g:0 b:0

    -in any blu ray movie will you not find a black in the movie area that is r:0 g:0 b:0

    I can't link to LG talking about improved near-black level performance for 2017 models because I did not upload a recording of their representative at CES
     
  16. goonergaz

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    You said;

    "Come to think of it, no BD ever mastered has true black levels, correct?"

    Yet everyone here disagrees and suggests it's your settings. So we have you and some LG rep you spoke to at CES...I'm not suggesting he didn't say such a thing but really, what LG having issues producing true black vs Bluerays not being able to produce black are two completely different discussions. I was hoping an LG statement might clear where you're going wrong.

    I suggest you try setting up your TV and coming back - you can buy a proper disk for such a thing if you don't want to use the link I provided, then at least you will remove the difference between the black bars and pure black within the film...then you will be left with the best blacks your TV can produce.

    Here's another link which looks a little better;

    http://www.techhive.com/article/2079503/easily-calibrate-your-new-hdtv.html
     
  17. Shifty Geezer

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    Black in movies (Blu Ray, DVD, broadcase, internet stream) use Limited RGB, using a range of 16-235 to represent the range of value from true black to brightest white. Any values at 16 or below should be shown as true black on your TV. The ability for console to switch between full RGB and limited RGB results in content either too bright in the blacks when viewing limited RGB content in Full RGB mode, or suffers black crush viewing full RGB content on Limited RGB mode.
     
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  18. ProspectorPete

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    I know how to change the black level. I did this in 2009 I think.

    On every 21:9 blu ray, there is a difference between the black borders and the blackest black of the movie, which would be at the end credits.

    Read the bolded part again.

    If the black borders are encoded as r:0 g:0 b:0 < this is true black then if the rest image is less black, then the actual movie is not true black. Yes, you can change tv settings, but that will never change that the movie part never uses r:0 g:0 b:0 true black.

    You can use tv settings to make grey appear as true black, so "just change your tv settings!" has nothing to do with this.
     
  19. ProspectorPete

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    In REC 709 color gamut, black is not defined as r:0 g:0 b:0, however, on a blue ray it is. Would that explain the difference?
     
  20. Silent_Buddha

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    You still don't get it. Movie content regardless of source is mastered (home consumer market) with black at 16 and not 0.

    Only plasma and OLED TV's have the potential to show black levels approaching 0 when other content is being displayed. This is due to their ability to turn off light emittance at the pixel level. LCD's can only turn off light emittance for blocks of pixels at best. How large the blocks are depends on whether it is using LED edge lighting (common and very large blocks) or LED back lighting (uncommon). In the case of LED backlighting that's further refined by how many lighting zones there are. Even the best LCD panel can't block all light emittance from the backlight, hence why there is blooming and light halos on dark scenes. Even CRT TVs back in the day couldn't reproduce true black due to the way cathode ray tubes worked.

    It is assumed that all LCD panel TVs can display a difference in black level between 16 and 17 but may not be able to between 15 and 16. This is the reason why true black for movie mastering for consumer distribution uses true black as 16 and not 0.

    Now, some TV's can display differences in black levels below 16. This will cause the issue you see where "Black" on a DVD/BRD looks grey compared to the "Black" bars above and below the picture. Note that even those black bars above and below the picture aren't at 0. In general it'll be somewhere between 10-16.

    This is easily seen if you have the ability to block out all light in your room, not easy to do unless that room has absolutely no windows and there are absolutely no light sources in the room (including LEDs from electronic devices. Have your TV on, but displaying no picture and you'll see that your TV is actually emitting a dark grey glow. If you can't see it, then you're either blind or your TV has actually turned off.

    Because of this behavior, all TV's need proper calibration not only for proper color reproduction but for proper gamma and contrast to ensure they have proper black and white levels for the lighting in the room when playing back video content that is mastered with black levels set to 16.

    The problem with past LG OLED panels wasn't the ability to show deep blacks. It was that as you got below 16, it would start to show banding between the grey levels as it approached black. This was due to how the OLED pixels reacted to the low levels of electrical input in dimming the light that they were emitting.

    The 2017 LG panels have been reworked to address this issue. Even with that problem, many videophiles still preferred OLED panels made before 2017 because you get much closer to true black when viewing movie content than you could with the best LCD TVs.

    I really do not have time to be making large posts right now, but hopefully this will help you to understand how things work and why you are seeing what you are seeing.

    Regards,
    SB
     
    #20 Silent_Buddha, Mar 25, 2017
    Last edited: Mar 25, 2017
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