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HDMI Black Level

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Marcus Garfunkel
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Hello,

I have a BrightSign XD233 connected to an LED wall. When I send a black image to the wall, there is a very dim "grey" color visible. This is not noticeable when connected to a standard LED Monitor, but definitely visible on the LED Wall. 

Is there a way to adjust the black level of the HDMI signal coming from the BrightSign?

We'd like to use a black image to turn the LED Wall "off" but it does not output a signal black enough for that effect.

Thanks,

Marcus

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    Ben Conwy

    Having this same issue. It's like they're limiting the dynamic range. I've had the same issue with HDMI outputs from a PC. Not sure if there's any functionality that can help with this. We're sure it's not in content because the blacks are true black when we come out of a Mac or PC into the LED Controller.

     

    Brightsign can you please help?

  • 0
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    Ben Conwy

    Update, if I run the signal through a Decimator MD-HX and come out SDI then my blacks are where they should be. Not an ideal workaround, but it will do. 

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    Nathan

    I had the same issues and heard the following from Brightsign support:

    In TV resolutions (1280x720, 1920x1080, etc) the player output TV/video signal in YCbCr format, rather than computer/graphics RGB.
    TV/video black is not true RGB black, as that's "Superblack" and is special in broadcast TV land, along with pure white, "Superwhite."

    So if you can feasibly drive the player at a computer resolution rather than a TV resolution, that might give you the blacker black that you need.

    Another potential fix would be to use Video Powersave to turn off the video output, assuming the LED processor is okay with that.

    and this:
     
    Technically you can change modes via roVideoMode, but changing modes usually requires a reboot, so you'd need to implement the change via a custom autorun which gets messy since you'd need to reapply your change every time you update BrightAuthor, unless you write your own script which is even more work and maintenance.
    http://docs.brightsign.biz/display/DOC/roVideoMode

    I just noticed that DVI uses RGB Full for all modes, so if your wall processor has a DVI input, that may be the way to go.  It might work to do a HDMI->DVI->HDMI conversion as well, since the HDMI connection knows whether it gets dropped to DVI or not. 
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