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Decklink in editing, visual effects and color grading?!

PostPosted: Wed Jul 11, 2018 1:34 am
by TonyK47
Could please someone explain to me how could a DeckLink card benefit editing, visual effects or color grading? From what I understand it consists of expansion ports which can be used for sending or receiving signals. How does that refer to editing, visual effects or color grading? Am I missing out on something?

Also, how many outputs and with what resolution can I get from the 1) DeckLink 8K Pro, and 2) DeckLink 4K Extreme 12G?

Am I correct that you can get 1 8k input or output on DeckLink 8k Pro and 2 4k inputs or outputs on DeckLink 4k Extreme 12G?

Re: Decklink in editing, visual effects and color grading?!

PostPosted: Wed Jul 11, 2018 3:01 am
by Craig Marshall
The need for a Decklink is often confusing for new users and we were all new users once. The 'Decklink' interface in all it's various guises, (PCIe or Thunderbolt versions) effectively guarantee that you see a genuine Video signal on your Reference Monitor, not your Computer's interpretation of a Video signal. If you were to connect your Reference Monitor directly to your GPU as Gamers do for example, your pictures are likely to be influenced by your Computer's fixed or user configurable GPU settings.

The next part of the equation is your choice of Reference Monitor and how it is Calibrated. Most Computer Monitors are not suitable for Commercial colour grading but as true SDI 'Video' Monitors are often too expensive for freelance, semi-pro and hobby Resolve users, some high end 10bit IPS PC monitors can be accurately calibrated to say, Rec.709 either internally, if they have hardware 3D LUTs built in or externally through additional devices. On theses monitors, Display Port is commonly used and sometimes HDMI 2.0 and above inputs can be employed successfully.

After you decide which Decklink solution suits your Delivery Market and your Budget, your choice of Reference Monitor will depend on whether you need to Monitor in 8bit, 10bit, sRGB, Rec.709 and/or in either 4:2:2 or full RGB 4:4:4.

As an example, we see full 10bit RGB 4:4:4 from a Rec.709 calibrated IPS Computer Monitor using a 12G speed Decklink SDI 4K Pro card in conjunction with an SDI to Display Port converter. Our particular Decklink 4K Pro card (recently superseded by the new 8K model) has two SDI outputs: #1 > 4K and #2 with hardware downscale from 4K to HD. This allows us to grade 4K material on our calibrated native HD monitor whilst directing the 4K timeline feed from SDI #1 to a big 4K 'client' TV.

Re: Decklink in editing, visual effects and color grading?!

PostPosted: Wed Jul 11, 2018 2:04 pm
by TonyK47
Haha, man, this is all so confusing :D Thanks for the thorough information!

So basically it sends a signal to a reference monitor with different parameters without distorting it in any way? And you also get to have an extra output to slap the video on a big 4k screen for your client?

Just out of curiosity, what would've been the scenario without the Decklink in this case? :geek:

Re: Decklink in editing, visual effects and color grading?!

PostPosted: Wed Jul 11, 2018 9:44 pm
by Craig Marshall
Unless things have recently changed, the only way you will see a full screen display on your particular reference monitor is through a Decklink interface. Although you could run multiple outputs from your Graphics card say, to a 4K TV plus various HD monitors, all you will see is the GUI screen, not a full screen Video display. Think of a Decklink device as your 'license' for using Resolve. Free or Studio, it guarantees a proper, stable Video picture out of a Personal Computer. As mentioned previously, your choice of Reference Monitor and how it is connected, and calibrated is another matter entirely. A reliably configured seat at the DaVinci table is not as low cost as many first assume though it is Peanuts compared with what it would cost you just a decade ago.

As an example, we use Lightworks to Edit and Resolve to Grade and Finish. Lightworks supports both F12 'Full Screen Display' on a second Monitor as well as BMD's 4K Decklink SDI card. During an Edit, we can switch our Reference Monitor between the Lightworks full screen, 8bit sRGB output and the 10bit SDI output from the Decklink card connected to the same Monitor's Display Port. (latter is calibrated for Rec.709) Even taking into account the calibration variations, the differences in picture quality are very, very obvious.