RGBA images don't blend well in VSE with Cross Effect Strip #38598

New Issue

Bob · 2014-02-11T16:32:55+01:00

Bob commented

2014-02-11 16:32:55 +01:00

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.

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. ```

Bob commented

2014-02-11 16:32:55 +01:00

Changed status to: 'Open'

Bob commented

2014-02-11 16:32:55 +01:00

Added subscriber: @Bollebib

Terry Wallwork commented

2014-02-11 17:32:48 +01:00

Added subscriber: @TerryWallwork-1

Terry Wallwork commented

2014-02-11 18:32:51 +01:00

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.txt

VSEAlphaTest.zip

VSE-Screenrecord.webm

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.txt](https://archive.blender.org/developer/F76921/system-info.txt) [VSEAlphaTest.zip](https://archive.blender.org/developer/F76922/VSEAlphaTest.zip) [VSE-Screenrecord.webm](https://archive.blender.org/developer/F76923/VSE-Screenrecord.webm)

Bob commented

2014-02-11 20:56:40 +01:00

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.zip

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.zip](https://archive.blender.org/developer/F76938/VSEAlphaTest.zip)

Bob commented

2014-02-11 21:05:21 +01:00

This comment was removed by @Bollebib

*This comment was removed by @Bollebib*

Terry Wallwork commented

2014-02-11 22:28:04 +01:00

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

Terry Wallwork commented

2014-02-11 22:37:52 +01:00

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

Terry Wallwork commented

2014-02-11 22:48:12 +01:00

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).zip

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).zip](https://archive.blender.org/developer/F76958/CrossFadeWithWithoutAlpha_Corrected_.zip)

Sergey Sharybin commented

2014-02-12 08:30:12 +01:00

Added subscriber: @Sergey

Sergey Sharybin self-assigned this 2014-02-12 08:30:20 +01:00

blender-admin commented

2014-02-21 09:03:33 +01:00

This issue was referenced by blender/blender-addons-contrib@b3bc9e4f77

This issue was referenced by blender/blender-addons-contrib@b3bc9e4f775ed285d1431086c4cb86b3e2a8e0c2

blender-admin commented

2014-02-21 09:03:33 +01:00

This issue was referenced by b3bc9e4f77

This issue was referenced by b3bc9e4f775ed285d1431086c4cb86b3e2a8e0c2