US Patent 7472058 Automatic audio source detection for capture devices

A method for selecting an audio source when capturing audio data with at least one capture device includes connecting an audio source to an audio input port of the capture device, turning off the output of the audio source, calculating first signal strengths of the audio signals detected through the audio input ports of the capture device, turning on the output of the audio source, calculating second signal strengths of the audio signals detected through the audio input ports of the capture device, calculating a signal change between the first signal strength and the second signal strength of each audio input port, and selecting the audio input port with the largest signal change.