In video editor Color does not allow Alpha Under. It works in 4.1 but not 4.2 #121190

New Issue

Stuart-Waymire · 2024-04-28T18:56:48+02:00

Stuart-Waymire commented

2024-04-28 18:56:48 +02:00

System Information
Operating system: Linux Ubuntu
Graphics card: Nvidia-340

Blender Version
Broken: (example: 2.80, edbf15d3c0, master, 2018-11-28, as found on the splash screen)
Worked: (newest version of Blender that worked as expected) Works in 4.1, not 4.2 alpha

Short description of error Color Effect Strip does not work with Alpha Under

Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
In Video Editor, Add an image to the scene which is smaller than the view size and extend the frames of the image. Now do an Add Color (default is black) and extend its frames. This will cover the underlying image. When working correctly in previous versions, you can then set the Color Effect Strip to "alpha under" so the image appears over the black background. This no longer works in 4.2, either for old videos I created in previous versions, nor if done from scratch.

**System Information** Operating system: Linux Ubuntu Graphics card: Nvidia-340 **Blender Version** Broken: (example: 2.80, edbf15d3c044, master, 2018-11-28, as found on the splash screen) Worked: (newest version of Blender that worked as expected) Works in 4.1, not 4.2 alpha **Short description of error** Color Effect Strip does not work with Alpha Under **Exact steps for others to reproduce the error** Based on the default startup or an attached .blend file (as simple as possible). In Video Editor, Add an image to the scene which is smaller than the view size and extend the frames of the image. Now do an Add Color (default is black) and extend its frames. This will cover the underlying image. When working correctly in previous versions, you can then set the Color Effect Strip to "alpha under" so the image appears over the black background. This no longer works in 4.2, either for old videos I created in previous versions, nor if done from scratch.

ColorError.blend1

641 KiB

ColorError.blend

641 KiB

GreekHelmet.jpeg

151 KiB

Stuart-Waymire added the

labels 2024-04-28 18:56:48 +02:00

Richard Antalik commented

2024-04-29 07:51:57 +02:00

I guess this is broken by f4f708a54f

Perhaps a solution would be to skip calling OpaqueQuadTracker::add_occluder if blend mode is alpha under? After checking this quickly it doesn't seem to work though.

It doesn't help that seq_render_strip_stack() is still a bit confusing to follow. I will strongly consider rewrite before even looking into this.

@aras_p Perhaps you can come up with something before I get to this?

I guess this is broken by f4f708a54f9feb1788ed7f1a3d6d16072c8008cd Perhaps a solution would be to skip calling `OpaqueQuadTracker::add_occluder` if blend mode is alpha under? After checking this quickly it doesn't seem to work though. It doesn't help that `seq_render_strip_stack()` is still a bit confusing to follow. I will strongly consider rewrite before even looking into this. @aras_p Perhaps you can come up with something before I get to this?

Richard Antalik added

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In video editor Color does not allow Alpha Under. It works in 4.1 but not 4.2 #121190