I have followed the instructions here: http://kdenlive.org/user-manual/downloading-and-installing-kdenlive/installing-source

I am compiling all to the /opt directory

--prefix=/opt

ffmpeg, frei0r, mlt, all compile fine.

But Kdenlive stops compilation at


-- checking for module 'mlt++'
-- package 'mlt++' not found
CMake Error at cmake/modules/FindLIBMLT.cmake:70 (message):
Could not find MLT++


Sorry, I know this is probably very basic, but I am a noob when it comes to these things.

any takers?

If you are on Ubuntu or similar, it may be easier to use packages rather than compiling, that doesn't help your problem at all though.

I have no knowledge of this though I'm sorry, but I am guessing the pre-requisite packages have not been met, MELT by the looks of it, is it installed?

Well, maybe a bit (very) late. Nevertheless:
If you installed also the libs (frei0r, mlt) in /opt, the default configuration scripts will not find it there. You might be able to fix this by issuing
cmake -DCMAKE_INCLUDE_PATH=/opt/include ........
but I don't know much about cmake and if that breaks something else. You also might have to do the same for the libs, using CMAKE_LIBRARY_PATH.

Apart from that, the 'policy' for /opt is to use it for packages that do not follow the standard directory layout and therefore should install in /opt//.....
Is there a specific reason for using /opt and not /usr/local?