So I watched a video tutorial for Kdenlive in which the guy used the Curves effect and looked for it. When I didn't find it in my Kdenlive, I found out that it was contained in frei0r, which I promptly decided that I wanted.

But I'm stuck. I tried to install it according to the directions given in http://www.kdenlive.org/user-manual/downloading-and-installing-kdenlive/installing-source/installing-frei0r

So I did:
git clone git://git.dyne.org/frei0r.git
cd (file path) frei0r <----I don't remember the exact file path but I found the right one
sudo mkdir build (the site says to do 'mkdir build' but it said access denied or something)

but when I try
cd build && cmake .. -DCMAKE_INSTALL_PREFIX=/usr && make -j3

It tells me "CMake Error: The source directory "/usr/lib64/frei0r-1" does not appear to contain CMakeLists.txt."

Has anyone else run into this problem? I'm not a Linux expert so I'm kinda stuck.

Does Frei0r from Ubuntus repositories not include the curves filter? via Synaptic

Alternatively perhaps use Sunabs PPA for kdenlive including MLT & Frei0r I think.

If you're going to compile your own you'd be better specifying /usr/local whatever to keep your hsnd rolled binaries seperate from Ubuntus Repositories. Conflicts with other software will happen otherwise.