Abstract
In this paper, we propose a multi-level attention model for the weakly labelled audio classification problem. The objective of audio classification is to predict the presence or the absence of sound events in an audio clip. Recently, Google published a large scale weakly labelled AudioSet dataset containing 2 million audio clips with only the presence or the absence labels of the sound events, without the onset and offset time of the sound events. Previously proposed attention models only applied a single attention module on the last layer of a neural network which limited the capacity of the attention model. In this paper, we propose a multi-level attention model which consists of multiple attention modules applied on the intermediate neural network layers. The outputs of these attention modules are concatenated to a vector followed by a fully connected layer to obtain the final prediction of each class. Experiments show that the proposed multi-attention attention model achieves a state-of-the-art mean average precision (mAP) of 0.360, outperforming the single attention model and the Google baseline system of 0.327 and 0.314, respectively.