Method and system for generating and processing multiple independent input data streams based on a high priority OS message framework such as an OS provided framework for processing mouse-messages. Multiple input devices generate motion that is sensed by motion sensors located on one or more motion sources, quantify the sensed motion, and provide resulting input data to a computer via one or more communication ports. One or more software subroutines process the provided data, separating them into multiple independent input streams according to their sources, and sending the streams to listening applications. The subroutines are preferably integrated at a low level of the OS architecture, thereby enabling low-latency, fully-functional high priority processing of the input data.