We present an audio-visual multimodal approach for the task of zeroshot learning (ZSL) for classification and retrieval of videos. ZSL has been studied extensively in the recent past but has primarily been limited to visual modality and to images. We demonstrate that both audio and visual modalities are important for ZSL for videos. Since a dataset to study the task is currently not available, we also construct an appropriate multimodal dataset with 33 classes containing 156,416 videos, from an existing large scale audio event dataset. We empirically show that the performance improves by adding audio modality for both tasks of zeroshot classification and retrieval, when using multimodal extensions of embedding learning methods. We also propose a novel method to predict the `dominant' modality using a jointly learned modality attention network. We learn the attention in a semi-supervised setting and thus do not require any additional explicit labelling for the modalities. We provide qualitative validation of the modality specific attention, which also successfully generalizes to unseen test classes.

本文提出了一种基于视听多模态的零样本学习（ZSL）方法，针对视频进行分类和检索。作者证明了视听模态均对视频的ZSL非常重要，提出了一个利用已有大规模音频事件数据集构建的视听多模态数据集，并通过嵌入学习方法实现零样本分类和检索任务中加入音频模态的性能提升，并提出了一种新的方法来预测'主导'模态，从而证明了该视听多模态方法在未知测试类中仍具有推广能力。

面向音视频零样本分类和检索的联合多模态嵌入