[Michael Mccune]

Glenn and Dmitry; … Next steps on exporting alpha from Resolve, intended for Fusion:

At this point, we think there are four codecs in Resolve that output alpha, two DPX codecs (DPX RGBA and DPX Alpha 8-bits)and two Quicktime codecs (Uncompressed BGRA and Uncompressed ARGB).

If I understand the alpha export process correctly–after Glenn’s helpful tip clarifying Dmitry’s statement that there is an Export Alpha option on the Deliver page if one selects Individual Clips–then the Resolve alpha exports should import into Fusion.

And then Fusion should alternately display the RGB video channels or the alpha channel by selecting the Color/Alpha button under each display window. Right?

Let’s try it:
In Resolve, a single clip in a new project with a simple window, say a circle in the center of the image.
Add the alpha output to the node tree.
In the Deliver page, select a codec, say, QT Uncompressed BGRA, and select Independent Clips and Export Alpha. Export.
Open Fusion, drop the BGRA clip in the flow editor, view the display.

Seems to work! The RGB video option shows the image with the window. And the alpha option shows the B/W alpha window. OK!

We are done, right? Not yet.

Try this same node tree and the same Deliver page settings but this time with QT Uncompressed ARGB (not BGRA): Fusion now has a problem with this codec.

The Fusion display for ARGB shows an image that is cropped and stretched horizontally (my circle window is distorted horizontally) and shows a grey scale RGB image. And the Fusion alpha display shows an opaque (white) screen as the alpha.

And the two DPX alpha export files don’t import into Fusion at all.

Dmitry or Glenn: am I seeing this correctly???

Thanks again, Mike

[Michael Mccune]

Thanks, Glenn; Really appreciate your help on this. And, yes, “individual clips” is mentioned in the documentation (page 1108).

BUT–I have to say, as an old English major–the documentation actually is not clear that it is NECESSARY to select, “Individual clips,” even when there is only one clip on the timeline. (This was my situation.)

Why is the documentation here unclear as written??? Because the purpose of this selection is to select how file(s) are output, either as a single file or multiple files. And if there is only one clip in the timeline, then the “Individual clips” choice is immaterial as it will always be a single file.

And there is no clue here that the alpha output option is hidden there.

But the actual necessity of this selection with regard to alpha output could easily be indicated by, for example, simply adding the the words, “… but alpha will be output ONLY if ‘Individual clips’ is selected, even if there is only one clip on the timeline.”

Dmitry, if you are reading this, please respond if you agree and please ask your team to clarify this point in the documention.

Thanks again, Glenn and Dmitry.
Mike

[Michael Mccune]

Dmitry; very welcome information. Thank you.

However, cannot see the check box option in the Deliver/Video page to Export Alpha.

Test setup, as simple as possible:
New project, add single short clip, picture of a face (or whatever);
Add simple window, say, around the face (perhaps adjust saturation and gain to make the effect obvious to ourselves that the window works;
Select the Node Key tab on the color page to view the key/power window, and, again, verify to oneself that the key exists at that point;
Select the Hightlight mode (shift-H), again, just to verify to oneself that the key exists there;
Add an alpha output to the node tree and connect the node key output.

Should be ready to go to the Deliver page and Export Alpha, right? OK.

In the Deliver page, choose one of the alpha codecs (for PC), such as DPX Alpha 8-bit (alpha only, no video), DPX RGBA, Quicktime Uncompressed BGRA or Uncompressed ARGB.

Look down the Deliver page Video column for the Export Alpha option you mentioned.: Don’t see it. Not for any of the above-mentioned four alpha output codecs for PC Resolve.

I do see the usual Video/Advanced option list that includes Aspect ratio, Data Levels, Data Burn-In, Use Optimized …, use Flat Pass and three check boxes for sizing and debayer. But no Export Alpha option.

Gotta be something simple, Dmitry. What am I missing??? This isn’t an Apple/PC issue is it???

Thanks again, Mike

[Michael Mccune]

Glenn; yes, the handles removed THAT visible offset.

By THAT visible offset I mean that all the visible spatial offsets did not disappear.

I discover–ah, it never ends–that there is another visible offset to deal with. I discover than my original clip needed a slight rotation to level the horizon. But THAT offset was not incorporated, it seems, into the rendered alpha output. Or, that it also needs the same rotation adjustment as the original.

As it is, the external matte image and the node tree image have a slight rotation misalignment.

The manual does discuss the order of operation with regard to sizing modes, but I have yet to understand how exactly this issue arises.

Onward and upward!
Thanks again, Glenn.

[Michael Mccune]

Dmitry; also, as you know, on a PC only the two Quicktime uncompressed alpha codecs are available.

And on a PC, two other alpha-labeled codecs, DPX Alpha 8 bits and DPX RGBA 8 bits are not in your list.

Did your tests show that those two DPX alpha codecs also work? On a PC???

Thanks again, Dmitry

[Michael Mccune]

Thanks for this list, Dmitry;

To get started, this list is also valid for Windows, correct??? I note that you begin your list by saying that these alpha codecs were valid for MAC OS.

Mike

[Michael Mccune]

Glenn; thanks for the thorough double-checking of this process.

And yes, one of the purposes of this round-trip within Resolve is to create an “archive” or version that is (re)usable outside of that timeline.

But, most importantly, your tests seem to reach the same general conclusion that 3 Resolve Delivery codecs work as keyable alphas when taken back into Resolve and that no Resolve codecs work in Fusion and only one in After Effects as an alpha component and none as an AE keyable alpha.

Dmitry, BMD Support said in this thread, [Dmitry Kitsov] “There are no issues with alpha channel as included by Resolve that we know of.”

But I wonder, as you do: [Glenn Sakatch] ” or do we need to do some other song and dance?” For example, to get them to work in Fusion, a close relative to Resolve.

At least the proper method is not obvious. Unless Dmitry meant to say that a B/W rgb image of the Resolve key is the only “alpha” that Resolve has and that it is, indeed, in lieu of a keyable alpha.

Thanks again, Glenn; Onward and upward!
Mike

[Michael Mccune]

Excellent tips, Glenn;

Your tips are at the level of detail I really miss in nearly all Resolve online training.

It seems that the workflow *implications* of some settings, such as handles, do not receive as much attention after pointing out the feature itself. For example, handles are discussed with respect to the benefit to editors: never occurred to me that, in this case, I may be sending those handles to myself as part of the external matte.

Perhaps a good topic that might be included by Patrick Inhofer in his Lynda.com Resolve Guru series.

Much appreciated, Glenn.

Checking handles. I suspect I will find 24 frames set for handles, so in and out handles together would equal the 47-48 frame offset I am seeing.

Thanks again, Mike

[Michael Mccune]

Thanks, Noah; Sorry but I have made a video recording so I would have to learn that; it would surely be helpful from time to time.

But very simple really: I want to mask (and track) a face for later color adjustments.

My goal is to export that face mask as a matte (along with its tracking, etc.). For this purpose most of the other nodes in this larger tree are disabled so the output is only of the face mask.

The larger purpose is to off-load some of the system video processing demands. This clip has a very large node tree (two dozen or more) and the processing, while it works, is thus bogging down the system. Thus if one has several face masks, this process would have to be repeated for each one to gradually lower the burden on the system.

That exported matte is then brought in via the External Matte process. It is used in lieu of the set of nodes that built the face mask. That is, a series of nodes that created the face mask would include a tracked window, one or two filer nodes, a key node (the filtered key fed to the video input of a node where it is tweaked using curves and blur).

Those original now-redundant face mask nodes are then deleted, resulting in a more compact and efficient node tree. This is a major reduction in the burden on the system when one has four or five such face masks, plus other masks throughout the long clips.

Anyway, this exported matte is re-introduced as an External Matte to take the place of the node sub-tree that can then be deleted.

OK. Works. I can see the external matte, make further adjustments to it as needed, etc., BUT …
there is a time code offset between the imported matte and the original clip. Visually, one can see the mask offset from the face due to some movement during those 47 frames.

For test purposes, I burned time code into the exported matte and so it can be compared on screen with the displayed time code of the original clip. It shows and offset, for me, consistently of about 47 frames.

Does this clarify the process and the problem??? Any thoughts would be appreciated.

Thanks, Mike

[Michael Mccune]

Thanks, Dmitry; Question: how properly to export alpha channels???

Which Deliver tab codec would you use to generate an alpha channel (RGB+alpha) for import into Fusion?

I am asking as I cannot seem to generate a 4-channel output, that is, RGBA, for Fusion.

Here are my steps: please correct any mistakes or note better ways to do this.

Base case:
1. I have a node (the last one in a very simple node tree) with a key mask feeding the output: the node tree output has both an RGB and an alpha output.
2. The key mask in the last node can be verified using the highlight mode which shows the individual node output (as opposed to the node tree output) and selecting the key tab;
3. On the Deliver page, I select a codec that should, I believe, generate a 4-channel output, such as QT Uncompressed RGBA.
4. The exported file is inspected for bit depth and the number of channels. But it shows only three channels in the output video. The output video is of the mask; in other words, it is a video version of the key mask: black surrounding the key mask area.
5. Checking the file metadata using MediaInfo, file manager properties or importing into Photoshop, all show only three channels.
5. Imported into Fusion, the video version of the key mask appears as expected; that is, a black area surrounding the key mask area. But there is no 4th or alpha channel. Selecting the Fusion button for color/alpha under the display window displays only a field of white (opaque).

Please clarify this and detail your approach to generating a 4-channel output from Resolve to be imported into Fusion.

Thanks again, Dmitry. I very much appreciate the help of your professional experience in this.
Mike