1. A computer implemented method of processing video data formed of a series of video frames comprising: using a first video encoding process an d feature-based encoding process, processing the video frames by: encoding the video frames with the first video encoding process; processing one or more of the frames to detect one or more instances of a feature by searching the one or more frames for a region of pels having coherency and computational complexity as compared to other pels in the one or more frames; modeling variation of the feature instance relative to other instances of the feature to create a feature-based encoding of the feature instance, wherein modeling variation of the feature instance includes: identifying other instances of the feature in other frames of the video series; aggregating two or more of the instances of the feature into a set; processing the feature instances in the set to create the models for the feature based encoding; comparing compression efficiency of the feature-based encoding of the feature instance relative to an encoding of the feature instance resulting from the first video encoding process; determining from the comparison which encoding enables greater compression efficiency; and using the results of the comparing and determining step, applying feature-based encoding to portions of one or more of the video frames, and applying conventional encoding to other portions of the one or more video frames.