0002737: Composite transition with opacity less than 100% gets pushed to 100% when no clip to compose with is present

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Project

Category

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Date Submitted

Last Update

0002737

Kdenlive

Transitions

public

2012-09-15 13:24

2012-09-16 00:30

Reporter

diveo

Assigned To

j-b-m

Priority

normal

Severity

minor

Reproducibility

always

Status

feedback

Resolution

open

Platform

Kubuntu 12.04

Linux

OS Version

Product Version

0.9.2

Target Version

Fixed in Version

Summary

0002737: Composite transition with opacity less than 100% gets pushed to 100% when no clip to compose with is present

Description

Composition opacity changes from its setting to 100% if there is no other clip to compose the clip with on which the translation has been set. At the moment, users thus need to work around this bug by adding explicit black clips to the timeline or they need to cut gaps into their composition translations ... which is a daunting task when overlaying emblems, etc. over longer video sequences.

Steps To Reproduce

1. Set up a clip in the first track, say, some emblem we want to overlay all other tracks. Add a composite transition to this track and low opacity, say, to 40% to make the bug clearly visible.

2. Add a clip below to the second track so that it get composed with the first track. Cut out a short part (gap) from this second clip so that there is a sequence in the timeline where we only have the first clip getting composed with nothing, so there is a gap in the second track.

3. Play or render the clip and watch what happens around and within the gap: compositing jumps from 40% to 100% opacity inside the gap and then returns back to 40% once the gap ends and a clip to compose with is on the second track.

Additional Information

I would expect opacity to stay at 40% regardless of whether there is a clip on track two to compose with or not. Currently, kdenlive users need to explicitly add black clips to the timeline in order to avoid this composition opacity bug.

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Notes
(0008350) j-b-m (administrator) 2012-09-16 00:30	Well, this issue is related to the way transitions work in MLT, and I see no way to easily fix it. If there is no clip on the lower track, the transition is not applied and the image of the upper clip is rendered "as is"...

Issue History
Date Modified	Username	Field	Change
2012-09-15 13:24	diveo	New Issue
2012-09-16 00:30	j-b-m	Note Added: 0008350
2012-09-16 00:30	j-b-m	Assigned To	=> j-b-m
2012-09-16 00:30	j-b-m	Status	new => feedback