Bug 409369 - dissolve ignores transparency
Summary: dissolve ignores transparency
Status: RESOLVED FIXED
Alias: None
Product: kdenlive
Classification: Applications
Component: Effects & Transitions (show other bugs)
Version: 19.04.3
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Vincent PINON
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-07-01 14:30 UTC by hadmut
Modified: 2021-03-04 19:18 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed In:
fritzibaby: Brainstorm+


Attachments
Example as described. (9.62 KB, application/x-kdenlive)
2019-07-01 14:30 UTC, hadmut
Details

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Description hadmut 2019-07-01 14:30:42 UTC
Created attachment 121260 [details]
Example as described.

SUMMARY

Put a title clip with transparent background over a video and add a dissolve transition to make it appear smoothly. dissolve will ignore the transparency of the background and will use the background as solid until end of dissolve transition. Then (after dissolve) the background is correctly transparent.)

STEPS TO REPRODUCE

Simply use the attached example file or

1. Put some video or constant color (other than black) on V1 track. 
2. create some title video with text and transparent background and put it over the video on V2.
3. add a dissolve transition
4. watch or render

OBSERVED RESULT

The dissolve transition uses the transparent background as if it were fully opaque. After the transition is finished, the background becomes transparent and composition works as expected.

EXPECTED RESULT

transparent background should be transparent during transition

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
Comment 1 hadmut 2019-07-31 15:17:05 UTC
Same problem seen when using PNG images with transparency as a layer.
Comment 2 hadmut 2019-08-13 15:44:10 UTC
Still exists in 19.07.90
Comment 3 emohr 2019-08-14 17:35:16 UTC
Thanks for reporting. Confirmed. 
Workaround: use the transition "composite and transform".
Comment 4 hadmut 2020-10-21 23:04:10 UTC
Seems to be fixed in 20.08.2
Comment 5 farid 2021-03-04 19:18:09 UTC
Yes, indeed it is fixed. Thanks for reporting.