Bug 397810

Summary:	Crash with Composite and Transform
Product:	[Applications] kdenlive	Reporter:	Attilio <atti84it>
Component:	Video Effects & Transitions	Assignee:	Vincent PINON <vpinon>
Status:	RESOLVED WORKSFORME
Severity:	critical	CC:	fritzibaby, matthew.linux
Priority:	NOR
Version First Reported In:	18.04.3
Target Milestone:	---
Platform:	Mint (Ubuntu based)
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	kdenlive console output gdb backtrace

Description Attilio 2018-08-23 23:41:43 UTC

I'm using Kdenlive 18.04.1 AppImage, on Linux Mint 18.3. MLT 6.7.0
I have a background and two title clips. When I add a "Composite and Transform" filter it suddenly crashes.
I'm new to kdenlive, if you tell me how to do, I can provide backtrace and the version of other libraries.

Comment 1 Attilio 2018-08-23 23:43:18 UTC

When I start Kdenlive from command line, I get this message on the moment of the crash:

QXcbConnection: XCB error: 3 (BadWindow), sequence: 1942, resource id: 19891012, major code: 40 (TranslateCoords), minor code: 0
/tmp/.mount_OrFRBF/AppRun: línea 56: 29340 Violación de segmento  kdenlive --config kdenlive-appimagerc $@

Comment 2 emohr 2018-08-24 14:42:31 UTC

Please run Kdenlive from console and post the output here (command: “./Kdenlive*.AppImage”). See here as well: https://forum.kde.org/viewtopic.php?f=265&t=130342

Comment 3 Pozsgay Máté 2018-12-10 01:52:18 UTC

I think I have encountered this issue as well.
It is pretty easy to reproduce. Just grab a clip, and a picture (I want to use it as a logo). Place the video in the timeline, and the image above. Apply the transform effect on the image. (You can leave the default settings) Start the project playback while both the videos are enabled, and it crashes.

Proxy clips mitigate the issue, but just a slightly better. Switching to "Preview" track compositing greatly reduce the likelihood of the crash.

I also noticed if I start the playback only the video enabled, then enable the logo track as well the playback goes on and the logo displayed as well. However seeking to another position while the playing back, or stop the playback, and restarting it is likely to cause crash again.

Comment 4 Pozsgay Máté 2018-12-10 01:54:54 UTC

Created attachment 116820 [details]
kdenlive console output

Comment 5 Pozsgay Máté 2018-12-10 01:56:02 UTC

Created attachment 116821 [details]
gdb backtrace

Comment 6 Pozsgay Máté 2018-12-10 02:19:29 UTC

A quick update. It just came into my mind I have enabled an experimental feature: multiple processing thread. From the symptoms it looks like to me it is some kind of race condition issue, so I set back the processing threads to the default 1, and since then no matter how desperately I'm bashing the timeline, start/stop playback, enable/disable tracks; it just works fine. So it seems it is really some kind of threading issue.

BTW, I'm using version 18.08.2 from ppa:kdenlive/kdenlive-stable on Ubuntu Bionic with a kernel 4.18.20-041820-generic.

Comment 7 emohr 2018-12-16 16:40:34 UTC

It seems the problem is solved. We closed this bug. If it still appears in the latest version, please feel free to re-open it and update the affected version number.