Can I get 4k 60 hz 4:4:4 (10 bit) with TCL 4 series and 980 Ti card? HDMI2 limits?

Discussion in 'General TV Discussions Forum' started by apoobean, May 22, 2018.

  1. apoobean

    apoobean
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    Card says:
    Dual Link DVI-I, HDMI 2.0, 3x DisplayPort 1.2

    TV says:
    3 HDMI 2.0 w/HDCP 2.2 (1 ARC)


    I'll be doing video editing, and have calibration tool, so want to set up the most accurate monitoring possible with this setup. Want as close to 4k 60hz 4:4:4 (10 bit) as I can get. Not sure exactly where to compromise if that exceeds HDMI 2.0 bandwidth, or if there's a way to bypass issues by outputting via display port and converting.... or even splitting into dual outputs into same tv to reassemble.


    If it matters, the 980 Ti is in a Mac, so I don't have the Nvidia control panel (thought there may be some other option to emulate it)
     
  2. next010

    next010
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    According to rtings TCL TV's require that the input label be changed to "computer/pc" in order to get 4:4:4 RGB output, if it does not automatically detect it's a PC and force it.

    You should be able to get 4K/60Hz, RGB 4:4:4, 8-bit SDR output from that. Anything else may bump into the bandwidth limits of the HDMI interface.

    Without a Displayport interface you are bound by the limitations of the HDMI port on the TV.
     
  3. EndlessWaves

    EndlessWaves
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    The limitation is in HDMI 2.0, so with the TV not having any higher bandwidth inputs there's nothing you can do about it.

    By 'TCL 4-series' do you mean something like this:
    TCL S Series 4k 2017 S405 Review

    What would be the closest approximation would depend on what you're monitoring. If you went for a standard gamut TV I'm guessing it's sRGB/Rec. 709 content in which case it's unlikely to be viewed at more than 8-bit.
     
  4. apoobean

    apoobean
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    Well, that's certainly one of the points of confusion. I'll be using only as pc output, so it should force pc mode, but other things I've read suggest that 4k 60hz 4:4:4 is beyond the 18Gbps limit of HDMI spec... so is the inference here that the tv port in question (when in PC mode) performs BEYOND that HDMI bandwidth limitation? If so, aren't there issues then with all the other points in the chain like the card's output port, and the cable?
     
  5. apoobean

    apoobean
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    Yeah, that's the one... So basically, I need a tv with display port input? That'd be a real bummer since these TCL's are not only in my budget, but score shockingly well on their post calibration ratings and this one in particular also does well on their gradient accuracy, etc... though has limited contrast. I'm thinking I can just work with it a bit dimmer, though, since I'm in a relatively dark room.

    I'm still trying to figure out exactly what I should be monitoring. I'm making videos for wide consumption on YT, so definitely not HDR, and I believe it all ends up in sRGB if I remember correctly. I've been told a number of times, though, that I should be working in an extended 10 bit color space to avoid certain issues when colors combine and effects are added... then dumbing down to sRGB on output.

    So... I'm trying to find the most accurate compromise given the equipment to see and edit in as high a quality as possible, then output in such a way that it works for YT, but the overall image remains as true as possible to the original workspace.

    So... I've been under the assumption that means I should be trying for 10 bit 4:4:4 working space, then compress the render down to sRGB.

    Is it a crazy idea to somehow split the outputs so half the screen is being served by one output on the 980Ti, and the other half is being served by the other output? This is the most powerful card I could get that didn't require additional power (and a mortgage), so really hoping I can make the investment pay off. I can still return the TV for 14 days if I have another that somehow works better in the sub $1k range (used is fine).
     
  6. EndlessWaves

    EndlessWaves
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    Only at 10-bit, it's within at 8-bit.

    There's no such thing, you'd be looking at an image editing monitor if you wanted a 10-bit 4:4:4 display.

    Colour depth (x-bit) and colour space (gamut) are not the same thing.

    Colour space is the range of colours that can be displayed, while colour depth is the number of shades - essentially how close neighbouring shades are.

    A wider colour space is typically accompanied by a higher colour depth because otherwise you'd have shades spaced further apart - meaning more situations where banding is unavoidable.

    It's a general recommendation in mathematics and computing to store intermediate results in greater precision than the final output. It just prevents rounding errors and their analogues in other fields.

    I'm not an expert in image editing, but I suspect 10-bit sRGB output is a serious case of diminishing returns
     
  7. apoobean

    apoobean
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    OK, thx.

    It appears from other conversations that I need to establish a rec709 workspace, set card output, and calibrate the set accordingly. The last point of confusion is that I'm being told that although I'm outputting at 8 bits, I should work at a higher internal bit rate due to the interaction of the colors as effects are being added to avoid banding and other artifacts from the effects.

    So I guess I'm still unclear as to whether that interim higher bitrate is simply an internal matter within the editing software, or something I need to accommodate in the card's settings and output to the TV. Asking around on that one.
     

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