2B includes both a client side portion e. g. , the client side module and a server side portion e. g. , the server side module. The division of functionality between the client and server portions of operating environment can vary in different implementations. Similarly, the division of functionality between a video source 222 and the server system 164 can vary in different implementations. For example, in some implementations, the client side module is a thin client that provides only user facing input and output processing functions, and delegates all other data processing functionality to a backend server e. g. , the server system 164. Similarly, in some implementations, a respective one of the video sources 222 is a simple video capturing device that continuously captures and streams video data to the server system 164 with limited or no local preliminary processing on the video data.