VidTr: Video Transformer Without Convolutions
This addresses video classification efficiency for AI applications, offering a novel transformer design that is incremental in optimizing attention mechanisms.
The paper tackles video classification by introducing VidTr, a transformer-based model that aggregates spatio-temporal information without convolutions, achieving state-of-the-art performance on five datasets with 3.3x memory reduction and lower computational requirements.
We introduce Video Transformer (VidTr) with separable-attention for video classification. Comparing with commonly used 3D networks, VidTr is able to aggregate spatio-temporal information via stacked attentions and provide better performance with higher efficiency. We first introduce the vanilla video transformer and show that transformer module is able to perform spatio-temporal modeling from raw pixels, but with heavy memory usage. We then present VidTr which reduces the memory cost by 3.3$\times$ while keeping the same performance. To further optimize the model, we propose the standard deviation based topK pooling for attention ($pool_{topK\_std}$), which reduces the computation by dropping non-informative features along temporal dimension. VidTr achieves state-of-the-art performance on five commonly used datasets with lower computational requirement, showing both the efficiency and effectiveness of our design. Finally, error analysis and visualization show that VidTr is especially good at predicting actions that require long-term temporal reasoning.