[solved] Crash with face detection effect


kdenlive crashes when I use face detection, I have this message in the shell

kdenlive: symbol lookup error: /usr/local/lib/frei0r-1/facebl0r.so: undefined symbol: cvSetNumThreads



What version of kdenlive is this ?

Where do you find this effect? Because I am not sure this effect is supported in kdenlive.


This happens when some frei0r effects are not correctly linked when the frei0r package is built. How did you install MLT, Frei0r and OpenCV? , which distro / version?

I use kdenlive 0.9.4 with mlt 0.8.8, frei0r 1.3 and opencv 2.4.3, I installed them from sources as described here http://www.funix.org/fr/linux/index.php?ref=base-video and here http://www.funix.org/fr/linux/index.php?ref=montage
I also try the development version of frei0r and opencv but it's the same problem.


Ok, then if you compiled OpenCV yourself, there is a problem with the pkg-config file, I found the info here:


So you need to manually edit the opencv.pc file located in /usr/local/lib/pkgconfig.

After that, you need to make rebuild frei0r from scratch and the crash should be gone. Note that for the effect to work, I had to create a symlink:
sudo ln -s /usr/local/share/Opencv /usr/share/opencv

In my tests, the effect does not seem to work very well, I have some random spots appearing, not sure what is going on but at least no crashes.

Edit the .pc file like this (change the lines in bold):

# Package Information for pkg-config


Name: OpenCV
Description: Open Source Computer Vision Library
Version: 2.4.9
Libs: -L${libdir} -lopencv_calib3d -lopencv_contrib -lopencv_core -lopencv_features2d -lopencv_flann -lopencv_gpu -lopencv_highgui -lopencv_imgproc -lopencv_legacy -lopencv_ml -lopencv_nonfree -lopencv_objdetect -lopencv_photo -lopencv_stitching -lopencv_ts -lopencv_video -lopencv_videostab
Cflags: -I${includedir_old} -I${includedir_new}

Yes ! kdenlive doesn't crash anymore ! Thank you very much.

But as you noticed the effect doesn't seem to work very well.


Nice to see your windsurf looping detection don't crash Kdenlive anymore ...

Can you add a "Solved" to the title's initial post ? Useful for next readers

Thank's &