Blackmagic RAW green screen footage?

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Ryan Bloomer

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Blackmagic RAW green screen footage?

PostMon Sep 17, 2018 4:11 pm

Any one have any greenscreen examples shooting on Blackmagic RAW that they're willing to share for testing? Would love to see what this new acquisition format can do for pulling mattes.
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Nate Porter

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Re: Blackmagic RAW green screen footage?

PostMon Sep 17, 2018 4:42 pm

I don't typically do any green-screen stuff, but that said I might be able to hook you up if no one else has any.
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Ryan Bloomer

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Re: Blackmagic RAW green screen footage?

PostMon Sep 17, 2018 4:56 pm

Thanks for the offer Nate.

We can let this thread run for a bit and see if anyone has it already set up that they can just shoot a test.


I'm mostly curious to know how the matte's hold up at 12:1... and if they don't how far do you have to have less compression to get an acceptable matte. I'm currently working with ProRes 422HQ footage, and we still get quite a bit of compression artifacts when keying at this codec.
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Chris Frechette

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Re: Blackmagic RAW green screen footage?

PostMon Sep 17, 2018 5:52 pm

I'm also very interested in how well the 12:1 and Q5 key compared to lesser or non compressed.
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Robert Niessner

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Re: Blackmagic RAW green screen footage?

PostMon Sep 17, 2018 6:08 pm

I can do a test as soon as the UM46k also gets Blackmagic RAW...
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Nate Porter

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Re: Blackmagic RAW green screen footage?

PostTue Sep 18, 2018 4:26 am

In the morning I'll try to see if I can do a quick green screen test. Warning I don't have access to a proper green screen, but I thibk I got something that I hope will work for testing purposes. I'll get Q0 Q5 3:1 5:1 8:1 12:1 as well as prores 444 and 422 HQ since that's what you said you typically use and it will allow for better comparison of the codecs. I'll most likely use my sigma 18-35 as well.

Let me know your findings because I'm real interested in how well it works.
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Jamie LeJeune

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Re: Blackmagic RAW green screen footage?

PostTue Sep 18, 2018 8:39 am

I've got a 6x6 green screen somewhere. If I manage to find it, I'll run a comparison on Ursa Mini Pro between various flavors of BRAW and cDNG.

EDIT: Never got to it today. So, thank you Nate for running and posting green screen tests!
Last edited by Jamie LeJeune on Wed Sep 19, 2018 6:16 am, edited 1 time in total.
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Nate Porter

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Re: Blackmagic RAW green screen footage?

PostTue Sep 18, 2018 5:28 pm

I just did some quick tests. I haven't examined the footage yet but I did record a ton of different codec types in front of a green screen. Sorry they are short clips, but I didn't have much time to do it. Also this is by no means a great green screen test, but hopefully it is sufficient for learning about the codec and what it can handle under better circumstances.

File types I recorded
BRAW 3:1
BRAW 5:1
BRAW 8:1
BRAW 12:1
BRAW Q0
BRAW Q5
DNG 3:1
DNG 4:1
DNG Lossless
Prores 422 HQ
Prores 444
Prores XQ

Here is a link to the google drive folder https://drive.google.com/drive/folders/1MH2xLzaHsxILQpwlB5jt2gDYI8H-n7PY?usp=sharing

I'd love to know what information you can gather from these samples.

Edit: This was shot using sigma 18-35mm at f/4.0 and lighting was Aputure 120Ds on the background and a Aputure LS daylight bouncing off of foam core onto the talent.
Last edited by Nate Porter on Wed Sep 19, 2018 2:11 pm, edited 1 time in total.
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rick.lang

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Re: Blackmagic RAW green screen footage?

PostTue Sep 18, 2018 7:09 pm

Jamie and Nate, these kinds of tests should be added to the BMD website. They’ve shown some comparisons in the past. Maybe they do the same on a BRAW Page.


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rick.lang

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Blackmagic RAW green screen footage?

PostTue Sep 18, 2018 10:04 pm

I loaded all 12 clips on the same timeline so that is really mixing apples and oranges and bananas since my project can only use one Colour science. Resolve doesn’t have Gen 4 for footage from the URSA Mini Pro so I used the Pocket4K for my Input. So colour may be off. I ignored the actual colors for the moment and looked at the level of detail. Of course the much higher bitrates produce better quality than their lowest bitrates within the family. But the differences are remarkably slight on many shots as I found more than two years ago testing all the ProRes members of the family.

Now to the juicy stuff, and I mean the rarest of beef under the broiler versus the well done roast. And how to evaluate that? Everything in the frame at a glance seems to be cooked to a pleasant medium. Except if you ordered the synthetic cut of the grey top.

The CinemaDNG cuts are a riot of grey colour moiré that will draw your attention, but not in a good way. It looks great if you’re shooting to grab the attention of a preschooler. Now CDNG is a wonderful choice in all other regards (if you accept the workflow).

The ProRes cuts cook in a way that has been suggested by others before as the in-camera encoding of the same images almost gives you that perfectly even-coloured bland grey well done beef look that anyone shooting fashion and weddings craves to taste. We knew that before but rarely have we seen a controlled comparison between CinemaDNG and ProRes.

Personally, given I don’t yet have the option of shooting BRAW, although overall colour looks better in CDNG, when it comes to the wedding, I think I’m playing it safer by shooting ProRes 444.

And now what really matters to us. BRAW constant quality versus Q constant quality together in the same paella.

Colour in each of the BRAW dishes, whether constant quantity or quality, is virtually a perfect match. So the compression is all about details (and noise). Moiré is less prevalent in BRAW than CDNG. 3:1 is great but in motion 12:1 fares very well and as Note mentioned, if there’s a difference it may not be as important as saving storage.

3:1 versus 12:1, will depend on that balance of storage and it’s a little like asking which falls faster, a feather or a stone? If you’re shooting feathers 3:1 is your choice, but stones often weigh more and even 12:1 will be a very good choice when you’re not shooting feathers.

Q0 versus Q5: the hair has more detail in Q0. That’s likely best wherever detail is paramount. But Q5 does a very good job.

3:1 versus Q0: in my opinion Q0 visibly will reveal the greater detail in a complex scene, a knockout.

12:1 versus Q5 your decision which should depend on scene complexity and your key subject whether it be one or the other; in both cases, saving storage is a given.


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Last edited by rick.lang on Tue Sep 18, 2018 10:32 pm, edited 1 time in total.
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Jack Fairley

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Re: Blackmagic RAW green screen footage?

PostTue Sep 18, 2018 10:32 pm

I'm blown away by how well the 12:1 holds up. If you pixel peek you can see Q0 handles the fine hair better, as Rick has pointed out, but outside of vfx work, I don't think I would care.
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Will Vazquez

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Re: Blackmagic RAW green screen footage?

PostTue Sep 18, 2018 11:11 pm

Hey Nate, thanks for uploading the tests. Do you mind sharing what lens and light you used. The skin tones are lovely.

It seems like one can see a little moiré in your actor's shirt. The new de-mosaic algorithm has really reduced it from before though.
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Nate Porter

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Re: Blackmagic RAW green screen footage?

PostWed Sep 19, 2018 3:37 am

Will Vazquez wrote:Hey Nate, thanks for uploading the tests. Do you mind sharing what lens and light you used. The skin tones are lovely.

It seems like one can see a little moiré in your actor's shirt. The new de-mosaic algorithm has really reduced it from before though.


I used the sigma 18-35mm at f4.0. The green screen was lit with 2 Aputure 120Ds in their light domes and the talent was lit by a Aputure light storm (daylight version) bounced off a 4x6 sheet of foam core.

I know for the work that I do that is mostly web based delivery, I'm going to be opting for the lighter forms of BRAW. I love the speed and flexibility it gives me in post, and as I do most things in house by myself (unfortunately) it means implementing into my workflow won't be too much of a challenge.

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