Natural audio-visual interface between human user and machine requires understanding of user's audio-visual commands. This does not necessarily require full speech and image recognition. It does require, just as the interaction with any working animal does, that the machine is capable of reacting to certain particular sounds and/or gestures while ignoring the rest. Towards this end, we are working on sound identification and classification approaches that would ignore most of the acoustic input and react only to a particular sound (keyword).