1. A computer-implemented method comprising: receiving a video depicting at least part of a user performing a motor task; redacting features from the video which may identify the user; inputting the video to a trained machine learning system, the trained machine learning system having been trained to detect multiple sequences of location-dependent local motion features of videos which discriminate among a plurality of classes of the motor task; and receiving, from the trained machine learning system, a label identifying a motor task class of the plurality of classes, the plurality of classes including an indication of a performance level of the motor task based on at least one of the multiple sequences of location-dependent local motion features in the video detected by the trained machine learning system.