Bug 421306 (after, Blank, clips, screen, switching)

Summary:	Blank preview and rendered video after switching clips
Product:	[Applications] kdenlive	Reporter:	kenai1889
Component:	Rendering & Export	Assignee:	Jean-Baptiste Mardelle <jb>
Status:	RESOLVED FIXED
Severity:	major	CC:	julius.kuenzel, null
Priority:	NOR
Version First Reported In:	20.04.0
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description kenai1889 2020-05-10 21:30:32 UTC

SUMMARY
The preview screen, as well as the rendered video, are completely black after the point of switching video clip on the timeline (either manually, or by letting it play). It also affects the rendered video. That didn't happen on the previous kdenlive version.

STEPS TO REPRODUCE
1. Launch the program.
2. Add clips.

OBSERVED RESULT
The rendered video plays normally until the point of going into another clip, at which point it becomes completely black.
The previewed video becomes black either after playing until a clip change, or when manually going to another clip on the timeline.

EXPECTED RESULT
The video should keep playing normally, without becoming blank, as well as the preview screen should display it even after changing clip.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Void Linux, kernel 5.4.39; Plasma 5.18.5
(available in About System)
KDE Plasma Version: Plasma 5.18.5
KDE Frameworks Version: 2.70.0
Qt Version: 5.14.2

Comment 1 Julius Künzel 2021-02-25 18:06:32 UTC

Thanks for your Report! Can you please update to the latest version (https://kdenlive.org/en/download/) and report here whether this is still happening? Btw do you use the appimage? (It is highly recommended)

If it still occurs: does it only happen with a certain clip or a certain clip type (frame rate, file format,…)? What was the last version number it worked with? (MLT version would be interesting too: Settings > About Kdenlive) Can you maybe provide your kdenlive project file and/or an example clip to reproduce?

Comment 2 kenai1889 2021-02-26 06:52:31 UTC

I didn't use appimage. However, the bug has vanished after updating to a newer version of MLT (which happened a few months ago, sorry for not informing earlier).