DaVinci Resolve 17.4 Due to the specification change of the 3D keyer, the outside of the applied clip is displayed as a black band


In 17.4, I applied a 3D keyer to the clip for chromakey processing, but a black band is displayed other than the high line of the clip to be dealt with. 17.3.2 does not show black bars. I also have the same problem if I read in 17.4 what I created in 17.3.2. Is there any way to deal with this?


I'll check with the official support for their opinion and update the information when I know.
This matter was reported from the comment section of this site.

Same for 17.4.1. (2021/10/29)


The behavior of 17.3.2 and 17.4 is different when reducing the size of a clip that uses OpenFX 3D Keyer on the edit page with "Video" in the inspector.

17.4 results

Result of 17.3.2

Each behavior is summarized from 0:00 to 1:17 in the following video.

How to reproduce

A: General video
B: Chroma key processing
1. Overlay B on A on the timeline
2. On the Edit page, select [Effects]-[OpenFX]-[Filter]-[3D Keyer] for B clip ]
3. Select "OpenFX Overlay" at the bottom left of the timeline view
4. With the "Effect" and "OpenFX" eyedropper icons enabled in the inspector, select the color for alpha processing in the timeline view
.A black band is displayed outside the range of clip B that is reduced or moved with "Transform" or "Crop" of "Video" in the inspector.

How to work around the issue in 17.4 and later

In 17.4 there were enhancements and specification changes to the 3D keyer.
This will change the way you operate. In addition, when checking a clip with a 3D keyer of 17.3.2 or earlier in 17.4 or later, the menu of "OpenFX" in "Effect" of the inspector is displayed as "3D Keyer (Legacy)", and the operation is the same as in the old version. will be

17.4 "3D Keyer" will explain.

Select "Eyedropper +" (Add) in "3D Keyer" of "Effect" in the "Inspector" and select the black part.

Chroma key color processing is done before the black border.

Chroma key colors remain. In the "OpenFX" menu change "Despill" in "Behavior Options" from "0.000" to "1.000".

Adjust the border.

If a black frame remains, it will be removed. By changing "Pre Filter" to 0.000, it disappears.

In addition, it can be avoided by processing with Qualifier on the color page.

In 17.3.2, if you use "3D Keyer" on the edit page to save a project with chromakey processing and transparency, and then open that project, there is a problem that it is displayed without transparency processing.
This is the same when opening a project saved in 17.3.2 as well in 17.4. There is no problem with the newly set "3D Keyer" in 17.4. When the project is reopened, it will be displayed transparently without any problems.

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