Embodiments of the present invention are directed to methods and systems for performing automatic noise reduction in video. According to one aspect of the invention, a video noise-reducing system is provided consisting of a noise estimator, a motion classifier, two stages of filters, each including a spatial and temporal filter, and a combiner. The system adapts to noise level and to scene content to find at each location in the image a balance of noise reduction and detail preservation. Temporal Infinite Impulse Response (IIR) filtering provides a high level of detail-preserving noise reduction where motion allows, while non linear spatial filtering provides edge-preserving noise reduction in areas where the temporal filter would introduce motion artifacts. A spatial-temporal combiner provides smooth transition and balance between the two filtering modes; this block also enables use of external cues to produce a visually pleasing output based on ambient conditions.