Blackmagic Forum

Hey guys,

I'm wondering if I can use two separate decklink cards (one mini monitor and one mini monitor 4k) to output two separate feeds from resolve, one HDR and one SDR, or will i need to get the 8k pro decklink to output both feeds from one decklink. Ideally my HDR feed will have the 4k option so the duo cards aren't an option.

Thanks

Can Resolve do that?

To the best of my knowledge, your set your project for SDR or HDR, you can't do/see both simultaneously.

Yes if you have a decklink that has two SDI out, you can set one feed as HDR, and the second feed will provide an SDR reference after you analyze the grade through Dolby or HDR10+.

These options will not show or work if your decklink is the wrong model.

I have been successful using my Decklink 8k card to display side-by-side HDR-SDR using the option "Use dual outputs for SDI". I believe this is part of the DolbyVision workflow, so you'll need to enable that and you'll need to do an analysis pass to get the proper SDR trim that can play side-by-side with your HDR file.

I wrote up details in a posting I made earlier this week on the Feature Request forum (Thoughts on an HDR workflow 2.0).

Read that and let's continue the discussion!

Perfect thanks! I will most likely get the 8K decklink

Great info on your other post.

Reading through your workflow, that seems specific to youtube/online delivery correct? If you were delivering an IMF or Dolby XML to a platfrom like Netflix, they would be able to read the associated files to pull the HDR and SDR information. Am I correct in thinking this? You method is used because you're actually delivering two individual files for upload in their final HDR or SDR state with no information attached?

Also when you're talking about your two feeds HDR/SDR, are you saying you're limited to monitoring at one resolution. So you can't set one at UHD and one at HD?

uskiwisean wrote:Perfect thanks! I will most likely get the 8K decklink

Great info on your other post.

Reading through your workflow, that seems specific to youtube/online delivery correct? If you were delivering an IMF or Dolby XML to a platfrom like Netflix, they would be able to read the associated files to pull the HDR and SDR information. Am I correct in thinking this? You method is used because you're actually delivering two individual files for upload in their final HDR or SDR state with no information attached?

Not quite. For YouTube I am delivering one single file, which is the HDR grade plus the SDR LUT, wrapped together. I have never delivered to Netflix, but I'm quite sure that they would want similar deliverables: a high-quality, high-resolution HDR media file with an SDR LUT that provides the appropriate trims. But how do you make the SDR LUT? DolbyVision magic gives you a great start, and it could well be that when I have a license to use more of its features, I can get the trim passes of my dreams within the DolbyVision tool. But until then, I've found I have to walk a little bit off the reservation, and grading the trim pass with LUT-compatible operations puts me in a different, SDR-only, world. If I can get a trim pass that doesn't offend without going back to the HDR grade, then I'm ready to export the LUT (which requires that I be in an HD/SDR space). If I realize that my problems are upstream, I need to return to my HDR grade and make adjustments to still hit the marks there but also to make my SDR grade easier.

I've been reading commentary that some shows on Netflix are clearly not paying close attention to the SDR versions of their content, meaning that the SDR viewing audience is seeing mistakes in the automatic translation process. That's why you want to take the care to deliver a LUT that does what YOU want.

uskiwisean wrote:Also when you're talking about your two feeds HDR/SDR, are you saying you're limited to monitoring at one resolution. So you can't set one at UHD and one at HD?

The dual output for SDI option can only output a single resolution. With a Decklink 8K I have tested that it will output dual UHD streams, but I don't have two monitors that can both handle UHD. So I have to dumb-down the resolution to HD so I can monitor the SDR output on my DM-240. I think a conversion box could be purchased to decimate UHD to HD so I can monitor my HDR in full UHD, but I'm too cheap to spend the $600 right now. And I do virtually all my grading in UHD during the Assemble-Edit-Grade phase. When I'm doing the side-by-side, it's mainly about getting a good trim pass for the SDR grading phase. So UHD HDR monitoring is not so critical there.

Great info all makes sense. Sounds like even without the Dolby license you're able to make adjustment to the auto trim pass with a node or 2. This is a global change or are you able to do it shot by shot? When you're embedding that info is it difficult to explain how you're doing that? Are you reexporting metadata after you've made the HDR metadata?

As for the UHD to HD, I'm actually getting a black magaic SDI to HDMI converter for one of my signals , and it looks like that does auto UHD to HD conversion, so I'm wondering if that would do it. Thats about $185. I've found them used on ebay for 90 too.

For DolbyVision compliant workflow, typically you export an HDR compliant file (ProRes, DNX, etc. @ Rec2020 but DCI-P3 legal at 5600K, etc.).
An accompanying XML metadata is generated and part of the deliverable. A separate 2084 document with MaxFALL, MaxCLL, etc is filled and submitted.

SDR submission will depend on the broadcaster. Sometimes it is part of your HDR file with the metadata containing the SDR trim info. Or it could just be a separate SDR Rec709 standalone file.

Decklink 8k is the ONLY card that will do HDR+ SDR output in 4K/UHD via DolbyVision.
All other Decklink and UltraStudio cards can only do HD/2K.

Copy thanks so much for all that information.

I'm going to get the 8k card. I am going to run one of the SDI signals into the SDI to HDMI converter, which also happens to do UHD to HD convertion so it seems like i can set my output scalling to UHD, and the converter should kick out an HD signal to my HD monitor and keep the UHD signal to the 4k monitor, potentiality solving the single output scaling issue. I'll have to see if that actually works though.

In theory you can grade in 2K/HD and just have the same color space as you would with 4K/UHD HDR.

The downside of the Decklink 8K is it does not have an HDMI output so you cannot directly feed an LG OLED which can understand DolbyVision metadata! "HDMI Tunneling". It is a great workflow to watch 1000 nits on a Sony BVM and at the same time have HDR 600 nits or SDR on your LG OLED.

Right, I'm just hoping one of those Black magic SDI to HDMI converters will help solve the HD and UHD signals

One more question here if you wouldn't mind.

Why did you get the 8k pro over the 4k extreme deckling? Do you know if the both allow SDR and HDR? or is the 8k the only one?

The DeckLink 8K Pro card allows you to have dual SDI outputs in UHD/4K and the DeckLink 4K Extreme 12G only allows dual HD SDI outputs.

The DeckLink 8K Pro has no HDMI out.

Thanks that makes sense.

Have you ever tried to run the HDMI feed out of a graphics card now that Davinci allows full screen playback without a decklink through the “video clean feed” option?

Yes. You can use any available output on the system. I've tested up to 4 displays on Windows and Mac.

Dual GUI displays, plus a Video Clean Feed Display, plus a 4th display for whatever. You can drag scopes to the 4th display, but only if you are on the Cut, Edit or Deliver page.

But the Video Clean Feed can't be used for the dual HDR/SDR output setup.

Dwaine Maggart wrote:But the Video Clean Feed can't be used for the dual HDR/SDR output setup.

I'm using dual GUI screens and an HDR monitor (UP2817Q) for the clean feed. I'm not able to get the HDR metadata through to the clean feed monitor. It seems like the triple (and quadruple) monitor setups with a single graphics card only works for SDR (without purchasing extra hardware). Is this correct?

To clarify, if I want to grade an HDR project, I can't use clean feed and I'd still need a Decklink 4k Monitor card? Will an HDFury Integral work?

Dwaine Maggart wrote:The DeckLink 8K Pro card allows you to have dual SDI outputs in UHD/4K and the DeckLink 4K Extreme 12G only allows dual HD SDI outputs.

The DeckLink 8K Pro has no HDMI out.

Dwaine:
How does it look like for the Decklink 4k Pro?

Is it capable of:
*outputting simultaneously HDR and SDR on respective 12G SDI outputs in UHD.
*outputting simultaneously HDR in UHD to the SDI1 and SDR in HD (downconverter) on the SDI2
*downconvert UHD to HD whilst keeping 444 RGB format at 25/50 fps

Appreciate your help
Michal

bigabo wrote:

Dwaine Maggart wrote:The DeckLink 8K Pro card allows you to have dual SDI outputs in UHD/4K and the DeckLink 4K Extreme 12G only allows dual HD SDI outputs.

The DeckLink 8K Pro has no HDMI out.

Dwaine:
How does it look like for the Decklink 4k Pro?

Is it capable of:
*outputting simultaneously HDR and SDR on respective 12G SDI outputs in UHD.
*outputting simultaneously HDR in UHD to the SDI1 and SDR in HD (downconverter) on the SDI2
*downconvert UHD to HD whilst keeping 444 RGB format at 25/50 fps

Appreciate your help
Michal

Only the Decklink 8K is capable of simultaneous 4K HDR + tone map output. All other cards and breakout boxes are limited to HD/2K.

There is no automatic hardware-based downconvert from the 8K Pro.