I just installed kdenlive on my Slackware64 machine and it was an ordeal. Normally I use the SlackBuild site to get packages because I they are tailored to the Slackware environment and installs the packages more completely, but I ran into a problem with a broken/missing link for some of the dependencies so the process failed. Next I went to the GitHub page and downloaded the zip but it too ran into a snag with a missing dependency. At that point I had to resort to getting packages any way I could and from whatever source. Now I have a Frankenstein monster that generally seems to work but is seriously flawed.

When I run the Config Wizard, the "Installed modules" checks MLT version: 0.7.8, Melt (/usr/bin/melt), SDL module and the QImage module.
It shows a big red "X" for Avformat module (FFmpeg) and for DV module (libdv). The thing is, I definitely installed both of these packages. In fact I had FFmpeg 2.6 installed previously and I upgraded to 3.0 for this purpose. But Kdenlive isn't seeing it and as a result, when I try to load a video clip it always says, 'clip is invalid, will be removed from project.' It reads .jpg, .png, and .gif successfully but if fails on audio clips such as .wav or .mp3 just like it does .avi and .mp4.

The program also seems to fail in rendering although it doesn't show a failure until the program is closed. Then it complaints that the rendering was interrupted and the output file may be corrupted. Since the file is a .m2t I don't know what application to use with it. Kplayer certainly doesn't play it (it has zero length). Another symptom of missing libraries apparently.

This would be an issue for Slackware packagers not Kdenlive developers.