If the file does not exist, it will be created. If it does
exist, it will be overwritten. An overwritten file will
not be shortened if the captured data is smaller than the
original file. The file will be valid, it will just contain
extra, unused, data after the audio/video data.
A future version of this class will provide a method to copy
only the valid audio/video data to a new file.
This property cannot be changed while capturing or cued.