We propose music tagging with classifier chains that model the interplay of music tags. Most conventional methods estimate multiple tags independently by treating them as multiple independent binary classification problems. This treatment overlooks the conditional dependencies among music tags, leading to suboptimal tagging performance. Unlike most music taggers, the proposed method sequentially estimates each tag based on the idea of the classifier chains. Beyond the naive classifier chains, the proposed method groups the multiple tags by category, such as genre, and performs chains by unit of groups, which we call classifier group chains. Our method allows the modeling of the dependence between tag groups. We evaluate the effectiveness of the proposed method for music tagging performance through music tagging experiments using the MTG-Jamendo dataset. Furthermore, we investigate the effective order of chains for music tagging.

This paper proposes aligned contrastive learning for text-to-music retrieval. The proposed method introduces a new similarity measure, 'aligned similarity', which captures the frame-level and token-level correspondence within text and audio sequences. Unlike traditional approaches that aggregate sequence into clip-level and sentence-level embeddings, our method aligns the text token exhibiting the highest cosine similarity with each temporal frame of the audio sequence and averages these maximum similarity values across the entire sequence. This approach enables the capture of fine-grained relationships between audio and text that are often overlooked when sequences are aggregated into a single embedding. Retrieval experiments show significant performance improvements, with a notable gain being a 17.8% increase in Recall@5. Moreover, the alignment elucidates how specific audio frames correlate with textual tokens, enhancing the model's transparency and interpretability.

Independent deeply learned matrix analysis (IDLMA) is a state-of-the-art determined audio source separation method based on pretrained deep neural networks (DNNs). Owing to the excellent expression power of DNNs, IDLMA can handle a wider range of sources than conventional source models such as nonegative matrix factorization (NMF). However, owing to its supervised nature, the separation performance of IDLMA often degrades in the presence of timbral mismatches between the training data and the to-be-separated data. In this paper, we propose two source models that encompass the NMF- and DNN-based source models by constructing a prior distribution of the source power spectrogram (product of priors: PoP) on the basis of the product-of-expert concept. Since the NMF-based source model works well for a fully blind situation, the proposed models can handle the timbral mismatch without losing the expression power of DNNs. By introducing the PoP-based source models into IDLMA, we propose IDLMA extensions (PoP-IDLMAs) and derive their efficient parameter estimation algorithms on the basis of the majorization–minimization algorithm. Experimental results demonstrated the effectiveness of the proposed PoP-IDLMAs and that the proposed models greatly improve the source power estimation in frequency bands above 500 Hz.