View Issue Details

IDProjectCategoryView StatusLast Update
0000467Cinelerra-GG[All Projects] Bugpublic2020-07-03 22:30
Reporterskinkie Assigned ToPhyllisSmith  
Status assignedResolutionopen 
Product Version2020-04 
Target VersionFixed in Version 
Summary0000467: Transparant PNG in the Video, is rendered in the compositor without "feathered" edges
DescriptionWhen a transparant PNG is added to the timeline without any video content behind it, the compositor does not show anti-aliased / feathered edges. When a video is actually behind the image, the aliasing is visible.
Steps To ReproduceAdd test.png to the timeline, observe nofeathering.png, or add a video and get with-background.png
TagsNo tags attached.




2020-07-03 22:30

reporter   ~0003728

I think having "black" as the default to be blend with sounds what a user would expect.


2020-07-03 22:13

manager   ~0003727

GG looked at the program code. When you draw the transparent png, you are just seeing RGB and alpha set to 1. (It is read in with the alpha channels all set to 1). Aliasing is done with the value of the alpha channels and it takes 2 to do any blending. Until you add a background (or using the foreground plugin on another track) there is nothing to blend.

If you would like to have this work differently with being blended with black (I guess that would be the choice), GG said he could look into adding a Settings->Preference to allow for that. A Preference setting would be required so as to not affect pre-existing projects.
Let me know one way or the other if you think coding this is worthwhile and would be used (assuming GG can easily implement).


2020-06-27 21:04


nofeathering.png (21,856 bytes)
nofeathering.png (21,856 bytes)
test.png (353,175 bytes)
with-background.png (149,348 bytes)
with-background.png (149,348 bytes)

Issue History

Date Modified Username Field Change
2020-06-27 21:04 skinkie New Issue
2020-06-27 21:04 skinkie File Added: nofeathering.png
2020-06-27 21:04 skinkie File Added: test.png
2020-06-27 21:04 skinkie File Added: with-background.png
2020-07-03 22:13 PhyllisSmith Assigned To => PhyllisSmith
2020-07-03 22:13 PhyllisSmith Status new => feedback
2020-07-03 22:13 PhyllisSmith Note Added: 0003727
2020-07-03 22:30 skinkie Note Added: 0003728
2020-07-03 22:30 skinkie Status feedback => assigned