Maniphest T38598

RGBA images don't blend well in VSE with Cross Effect Strip
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Assigned To
Sergey Sharybin (sergey)
Authored By
Bob (Bollebib)
Feb 11 2014, 4:32 PM
Tags
  • BF Blender
Subscribers
Bob (Bollebib)
Sergey Sharybin (sergey)
Terry Wallwork (terrywallwork)

Description

W7
9800GT nvidia

blender-2.69-2038eb1-win64

-Use sequencer
-import 2 images (RGB)
-Blend 2 image strips overlapping each other with cross effect strip
-Set blend strip to "alpha over"


result: so far so good,a nice fade is the result

do the same process where one or 2 of these images were exported with an alpha channel (RGBA)


result: instead of fading,the second image pops in at full opacity and then does a bit of opacity changing,but not reliably good.

Revisions and Commits

rB Blender
rBb3bc9e4f775e Fix T38598: RGBA images don't blend well in VSE with Cross Effect Strip
rBAC Blender Add-ons Contrib
rBACb3bc9e4f775e Fix T38598: RGBA images don't blend well in VSE with Cross Effect Strip

Event Timeline

Bob (Bollebib) created this task.Feb 11 2014, 4:32 PM
Bob (Bollebib) raised the priority of this task from to 90.
Bob (Bollebib) updated the task description.
Bob (Bollebib) added a project: BF Blender.
Bob (Bollebib) edited a custom field.
Bob (Bollebib) added a subscriber: Bob (Bollebib).
Terry Wallwork (terrywallwork) added a subscriber: Terry Wallwork (terrywallwork).Feb 11 2014, 5:32 PM
Terry Wallwork (terrywallwork) added a comment.Feb 11 2014, 6:32 PM

I am using Blender Git Rev GIT2014-02-12-02-46-43-0e97550
on a Fedora 20 Box 64bit

I tried the instructions mentioned, and it looks like it works for me
but I am not sure.

So I have attached my system-info.txt file,
and a zip file containing the blend file I setup to test,
as well as the 2 png images I used (both have alpha)
made in Gimp.

I also did a screen record to show what I saw in VSE
if I did wrong let me know how to properly test.

system-info.txt8 KBDownload

VSEAlphaTest.zip199 KBDownload

Bob (Bollebib) added a comment.EditedFeb 11 2014, 8:56 PM

I looked at your file and at first glance it seems to be correct

I watched it again and now I see an issue with the blend you provided.

Look carefully at the end of the cross effect,it suddenly vanishes without fading

If you would invert the order of the files (Swap Inputs=ALT+S) then the issue would start at the beginning

I have added a few images and cross effect blends to your file to illustrate my point.

The blend all the way to the right is the correct one,it has normal RGB channels only.
All other blend effects are wrong (first frame pops in,or out,or the blend is strange)

VSEAlphaTest.zip2 MBDownload

Bob (Bollebib) added a comment.EditedFeb 11 2014, 9:05 PM
This comment has been deleted.
Terry Wallwork (terrywallwork) added a comment.EditedFeb 11 2014, 10:28 PM

Yes I see what you mean now. Only seem to happen when cross is set to alpha over.

Terry Wallwork (terrywallwork) added a comment.Feb 11 2014, 10:37 PM

Oops ignore previous post, seems all images have alpha even though i deleted the alpha from gimp before saving. Not sure why.

Terry Wallwork (terrywallwork) added a comment.Feb 11 2014, 10:48 PM

Ok definitely positively almost certainly this time the no alpha images actually have no alpha!!!

And I still get the full B image showing up when the cross strip is entered.

CrossFadeWithWithoutAlpha(Corrected).zip160 KBDownload

Sergey Sharybin (sergey) claimed this task.Feb 12 2014, 8:30 AM
Sergey Sharybin (sergey) lowered the priority of this task from 90 to Normal.
Sergey Sharybin (sergey) added a subscriber: Sergey Sharybin (sergey).
Sergey Sharybin (sergey) edited this Maniphest Task.Feb 21 2014, 9:04 AM
Sergey Sharybin (sergey) changed the task status from Unknown Status to Resolved.Feb 21 2014, 9:04 AM

Closed by commit rBb3bc9e4f775e.

Sergey Sharybin (sergey) edited this Maniphest Task.May 12 2014, 4:41 PM