There are various complicated posts online about installing ffmpeg on a mac so you can use it from the command line. I never quite have the patience for command line installations and often things did not work. But then I stumbled upon a much easier way…
First install Video Monkey, which as a GUI video processor is fantastic and my app of choice for video processing. http://videomonkey.org/. The drawback is you cannot customise the variables like video size and bitrate. You need ffmpeg on the command line.
Well I notice Video Monkey is only a GUI for ffmpeg which is installed with it anyway, its in:
So you can just call this line from the command line, with your required arguments after it, and use that ffmpeg!
To make life easier, just add this to the command line path by making a symbolic link to it in /usr/local/bin/ so you can use just ffmpeg on the command line instead of the full path above: sudo ln -s /Applications/VideoMonkey.app/Contents/Resources/bin/ffmpeg ffmpeg
So much easier than all the other websites on this topic!