Blackmagic Forum

Hi,

I do not know if this is a general bug or specific to Beta (I have Beta 8 right now).

Here is a test project that replicates the problem (150MB): https://drive.google.com/file/d/1kEmP9BSI4FPWKdYGyPJp4xU_x36A7JlO/view

Setup:
—Keying a video clip to get transparent BG
—Using that video in timeline.
—Applying colour correction to said video clip.
—Using a background image also colour corrected.

Problem:
—Some random pixels appear from time to time around the edge of the keyed clip.
—Applying a Lens Blur makes it very evident. Black/white/purple pixels pop up from time to time.

Notes:
—The moment colour correction is applied to the clip, the problems appear.

Remarks:
—When you render the test project (I use H265), you will see image defects especially on top right (beginning and end of the clip) and on top left (about in the middle of the clip).

Notes on this test:
—The key is not optimal.
—The colour correction either.
—I used those from another project to replicate the problem.

—Requirements are:
—Colour correction on keyed clip
—Colour correction on BG
—Then additional effects applied (like lens blur).

Desired solution:
—With the same setup, no weird pixels popping up.

I am interested in any solution that respects the parameters. I do not understand why this is happening, and it was quite difficult to replicate the problem. It is not as bad as in the other project, but the same behaviour (artefact pixels popping up) is present.

Thank you very much for any help or corrections.

Best regards.

Where are you keying the clip - Edit, Fusion, Color? Which key effect?

All your questions answered in the test project.

I wasn't planning on using that, but testing with my own project.