No software is free of bugs, those little pests which can make your video look or sound weird, or can suddenly close your project without warning. Sometimes it looks like computers have life... who knows. Some other times, however, the problem is between the keyboard and the chair :)
Although Kdenlive is already extremely useful and packed with functionality, it is not yet a finished product. As with any other software project, the development process, solves some bugs and create others. As of Aug 2009, the latest stable version is 0.75.
If you are using an older version, please update! This manual can not cover bugs and limitations which were corrected in the latest versions.
Your help is welcome to hunt bugs. The recommended steps for hunting bugs are as follows:
Reporting a bug
The recommended steps for reporting bugs are as follows:
Installing Kdenlive and MLT from SVN
First, make sure you install Kdenlive from SVN. Compile Kdenlive and MLT with debugging support:
./configure --prefix=your_path --enable-debug=full ; make clean ; make ; make install
When compiling, you may be interested in the log:
export LANG=C; make 2>&1 | tee kdenlive-compile.log tar -czf kdenlive-compile.tar.gz kdenlive-compile.log
You can automate the task of building a debug version of KDEnlive based on the current SVN sources of FFMPEG, MLT, MLT++ and KDEnlive by using the kdenlive-dev-helpers set of tools.
The kdenlive_builder.sh tool automatically builds a full unstripped version of KDEnlive and those libraries with debug symbols and places the build in the directory named ~/build/kdenlive_YYYY-MM-DD_HH_MM.
Such a build has to be launched by the special script kdenlive_launcher.sh.
In order to launch such a KDEnlive build with gdb or valgrind, simply modify the kdenlive_launcher.sh accordingly.
Rendering using inigo
The MLT command line player is inigo.
You can play or render a .westley or .kdenlive file with it. To play it:
inigo my_playlist.westley -consumer avformat:rendered_file.mpg real_time=0 [then add ffmpeg 's avformat specific parameters]
Publishing a gdb trace
gdb is an interactive debugger allowing to execute programs step-by-step, print the value of variables and display backtrace after segfault. When using gdb, you should try to compile kdenlive from sources directly, in order to use debugging symbols. Executables provided in GNU/Linux distributions are stripped (they do not include debugging symbols). When trying to reproduce a bug, it is highly recommanded to use the latest SVN version of kdenlive.
After segfault, ask for a backtrace:
For more complete information, prepare a log of your session with gdb:
script gdb kdenlive
Turn off pagination (everything will be available in the typescript file afterwards, anyways):
set pagination off
Then extract backtrace for all running threads:
thread apply all bt
and a verbose backtrace with listing of local variables:
- Can this be any more arcane? Isn't there an easier way? One copy and paste into the terminal at the beginning of the session to get the data you need?
Copy the output and publish a message on Kdenlive Bug reports forum, here:
Publishing a valgrind trace
Valgrind is a valuable tool for debugging and finding memory leaks. You may use the following options:
valgrind --leak-check=full --freelist-vol=100000000 --log-file-exactly=log.txt -v kdenlive
Create a tar file and append the file to your message on Kdenlive Bug reports forum:
tar -czf log.tar.gz log.txt
Kdenlive relies on MLT framework, which is the video editing engine. MLT framework relies on ffmpeg. The power of free software is to aggregate the work of thousands of developers.
- How to contact authors in case of a problem?
kdenlive bug forum
MLT mailing list
If your project does not run in inigo, post a report on MLT mailing list.
ffmpeg bug page
Ultimately, you may be interested to escalate to ffmpeg/libavformat project. ffmpeg deals with all video and audio codec and containers issues. To report a bug, visit ffmpeg bug report page.
- .75 - System freezes while rendering (Fedora 11)
- 0.7 - System freezes while rendering - see http://www.kdenlive.org/mantis/view.php?id=180
- 0.4/0.5 - Upgrading from previous versions causes the dialog boxes to be badly sized, and the application crashes when exiting. This is a bug in how Kdenlive manages it's configuration file. You can remove it: rm~/.kde/share/config/kdenliverc
- 0.5+ - If your install cannot find its MLT source, even after you have found it in /usr/lib or whereever it may be, and it still doesn't accept it -- remove the file at /home/youruser/.kde/share/config/kdenliverc Note this will reset any changes to the layout that you may have made; I am sure there is a better way to do this but I've not looked into it.
- 0.5 - Kubuntu and Ubuntu users may not be able to use some files with AAC sound, such as some MP4/M4V files. You will need to recompile the software following the directions here  after installing the list of needed libraries, also on that same page. Read here for more details: 
- 0.5 - Kubuntu and Ubuntu (Gutsy) users may not be able to use the firewire port directly inside Kdenlive, see . Just upgrade to dvgrab 3.1 will solve the problem.