MKP-Net: Memory knowledge propagation network for point-supervised temporal action localization in livestreaming

Standardized regulation of livestreaming is an important element of cyberspace governance. Temporal action localization (TAL) can localize the occurrence of specific actions to better understand human activities. Due to the short duration and inconspicuous boundaries of human-specific actions, it is very cumbersome to obtain sufficient labeled data for training in untrimmed livestreaming. The point-supervised approach requires only a single-frame annotation for each action instance and can effectively balance cost and performance. Therefore, we propose a memory knowledge propagation network (MKP-Net) for point-supervised temporal action localization in livestreaming, including (1) a plug-and-play memory module is introduced to model prototype features of foreground actions and background knowledge using point-level annotations, (2) the memory knowledge propagation mechanism is used to generate discriminative feature representation in a multi-instance learning pipeline, and (3) localization completeness learning is performed by designing a dual optimization loss for refining and localizing temporal actions. Experimental results show that our method achieves 61.4% and 49.1% SOTAs on THUMOS14 and self-built BJUT-PTAL datasets, respectively, with an inference speed of 711 FPS.