This document discusses multiple feature fusion techniques for facial expression recognition in videos. It reviews existing literature on using features like Histogram of Oriented Gradients from Three Orthogonal Planes (HOG-TOP), geometric warp features, Convolutional Neural Networks (CNNs), Scale Invariant Feature Transform (SIFT) and combining these features through multiple feature fusion to improve facial expression recognition from video sequences. The document also analyzes techniques like HOG-TOP for extracting dynamic textures from videos and geometric features to capture facial configuration changes caused by expressions.