Bug 350276

Summary: Segfault when adding a title clip after another using "Dissolve" transition
Product: [Applications] kdenlive Reporter: Paul Konecny <paul>
Component: Rendering & ExportAssignee: Jean-Baptiste Mardelle <jb>
Status: RESOLVED FIXED    
Severity: crash    
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Backtrace
Project File
Backtrace in Kubuntu with more symbols
Backtrace while screencasting

Description Paul Konecny 2015-07-16 07:03:02 UTC
Created attachment 93604 [details]
Backtrace

Version 15.04.3
Archlinux 64bit

Hello J-B, 
When I try to edit a video tuorial with kdenlive I get a segfault when I add two titleclips and try to do a Fade-in/Fade-out with the "Dissolve" transition (One normal, one reversed). When I add it to the timeline and try to do something with the second clip kdenlive segfaults.
I'll attch the backtrace and the project file.

Cheers!
Comment 1 Paul Konecny 2015-07-16 07:03:30 UTC
Created attachment 93605 [details]
Project File
Comment 2 Paul Konecny 2015-07-17 09:50:28 UTC
Created attachment 93617 [details]
Backtrace in Kubuntu with more symbols

Hi J-B, 
I tried it again with Kubuntu 15.04 with backports using Kdenlive 15.04.1.
Same result. 
I added a new backtrace with more symbols.
I saw you did some changes to master that sound like they could solve this problem http://quickgit.kde.org/?p=kdenlive.git&a=commit&h=e097fdb6a095bc909b9e7a1c3f203a3b5f4e743a
If so, any chance this will get backported to the 15.04 branch?
Cheers and thank you!
Comment 3 Jean-Baptiste Mardelle 2015-07-17 18:36:51 UTC
Can you please describe precisely every step that leads to the crash after opening the attached project file ? You are talking about 2 title clips in your description but there is only one in the project file. Do you add the same title clip twice in timeline ? please give me as much details as possible (on which track, etc) so that I can try to replicate...
Comment 4 Paul Konecny 2015-07-18 08:17:01 UTC
Created attachment 93637 [details]
Backtrace while screencasting

Hi J-B, 
I did a screencast for you showing exactly what leads to the segfault
https://www.dropbox.com/s/o4jujtknz73ihir/seg-cast.webm?dl=0
I also attached a new backtrace with symbols for ffmpeg und libav thinking that maybe using simple screen recorder at the same time has something to do with the issue. (SSR settings: webm 25000kb/s, 1080p, CPU 0 (slowest), Vorbis audio 192kb/s)
I hope this helps you!
Thanks!
Comment 5 Jean-Baptiste Mardelle 2015-07-19 20:01:51 UTC
Hi Paul,

Thanks for the screencast, that is perfect. I can confirm that the bug is reproducible with the Kdenlive 15.04.x branch, and that the crash does not happen with master branch.

However that is probably not related to the commit you mention. There were some important restructuring changes in master branch and I have no idea what fixed it.

I am currently spending all my time one the master branch since it will be released as Kdenlive 15.08 in exactly one month. There is no plan to release a 15.04.4 version, we don't have enough developers, and we need to concentrate on the 15.08. Sorry for the annoyance, I hope that the large refactoring effort that went in master will make it easier to maintain and fix Kdenlive.
Comment 6 Paul Konecny 2015-07-19 22:12:48 UTC
Hi J-B, 
absolutely no problem. I'll use master for now then. Just one question. 
I read in the refactoring wiki that there will be or already was a change in the file format. Will the format change again until release or can I start editing with master for now and be sure that 15.08 will work with these files?

Cheers and stay awesome ;)
Comment 7 Jean-Baptiste Mardelle 2015-07-19 22:42:19 UTC
There shouldn't be any more changes to the file format from now on, unless it's to fix a bug. The Applications/15.08 branch was just created by the KDE release team if you want to use that.

The 15.08 version might still have some big bugs that I missed, but I am doing my best to fix it all before the release - I have some spare time in the next 8 days so that is a good period for testing and reporting!
regards