Multitask Transformer for Cross-Corpus Speech Emotion Recognition

Deep learning has significantly advanced the field of Speech Emotion Recognition (SER), yet its efficacy in cross-corpus scenarios remains a challenge. To overcome this limitation, recent studies demonstrate the success of multitask learning, which uses auxiliary tasks to reduce difference between source and target dataset (or transfer knowledge from source to target datasets). Despite the efforts, the overall accuracy for cross-corpus SER is still relatively low and needs attention. To improve performance, we propose a multitask framework with SER as the primary task and contrastive learning and information maximization as auxiliary tasks. We design the auxiliary tasks innovatively to use the target data without emotional labels to develop a better understanding of the target data. The core of our multitask framework is a pre-trained transformer. While transformers have gained attention in SER, their application to cross-corpus scenarios is still limited. Multimodal approaches for cross-corpus scenario is substantially limited as well. We use text as the second modality, developing separate multitask transformers for audio and text and conduct decision-level fusion during inference. We use publicly available and widely used speech corpora, including the IEMOCAP, MSP-IMPROV and EMO-DB databases. The results demonstrate the benefits of the proposed approach, achieving improved performance on the benchmark databases in cross-corpus settings.