V4D: 4D Convolutional Neural Networks for Video-level Representation Learning
Authors: Shiwen Zhang, Sheng Guo, Weilin Huang, Matthew R. Scott, Limin Wang
Keywords: video-level representation learning, video action recognition, 4D CNNs
TL;DR: A novel 4D CNN structure for video-level representation learning, surpassing  recent 3D CNNs.
Abstract: Most existing 3D CNN structures for video representation learning are clip-based methods, and do not consider video-level temporal evolution of spatio-temporal features. In this paper, we propose Video-level 4D Convolutional Neural Networks, namely V4D, to model the evolution of long-range spatio-temporal representation with 4D convolutions, as well as preserving 3D spatio-temporal representations with residual connections. We further introduce the training and inference methods for the proposed V4D. Extensive experiments are conducted on three video recognition benchmarks, where V4D achieves excellent results, surpassing recent 3D CNNs by a large margin.