When checking the ffmpeg version OR while trying to convert the videos, you will receive error.
ffmpeg: error while loading shared libraries: libavdevice.so.54: cannot open shared object file: No such file or directory
This is because the ffmpeg which was compiled manually, has been corrupt. You just need to compile ffmpeg again & it will stop showing the error.
Login to your server via SSH.
# cd /usr/local/src/ffmpeg-0.xx.x
# make install
Performing the above steps will recompile ffmpeg on your dedicated server. Good to go ahead and convert videos now.