Please take a look at the screen capture of the media processing panel from my local instance of CA 1.7 dev. In the rows of the table involving FFMPEG--audio, video, QuickTimeVR--The application appears to be saying FFMPEG is available but cannot be seen by the application to process media. The paths are correct in external_applications.conf. I have other applications that also use FFMPEG and cand find it without issues. The same question applies to Libreoffice too.
I am running locally on OSX, with homebrew as the package manager. C/A was installed via GIT.