Music is used to convey emotions, and thus generating emotional music is important in automatic music generation. Previous work on emotional music generation directly uses annotated emotion labels as control signals, which suffers from subjective bias: different people may annotate different emotions on the same music, and one person may feel different emotions under different situations. Therefore, directly mapping emotion labels to music sequences in an end-to-end way would confuse the learning process and hinder the model from generating music with general emotions. In this paper, we propose EmoGen, an emotional music generation system that leverages a set of emotion-related music attributes as the bridge between emotion and music, and divides the generation into two stages: emotion-to-attribute mapping with supervised clustering, and attribute-to-music generation with self-supervised learning. Both stages are beneficial: in the first stage, the attribute values around the clustering center represent the general emotions of these samples, which help eliminate the impacts of the subjective bias of emotion labels; in the second stage, the generation is completely disentangled from emotion labels and thus free from the subjective bias. Both subjective and objective evaluations show that EmoGen outperforms previous methods on emotion control accuracy and music quality respectively, which demonstrate our superiority in generating emotional music. Music samples generated by EmoGen are available via this link:https://ai-muzic.github.io/emogen/, and the code is available at this link:https://github.com/microsoft/muzic/.

翻译：音乐用于传达情感，因此生成情感音乐在自动音乐生成中具有重要意义。先前的情感音乐生成工作直接使用标注的情感标签作为控制信号，这存在主观偏差问题：不同的人可能对同一首音乐标注不同的情感，而同一人在不同情境下可能感受到不同的情感。因此，直接以端到端的方式将情感标签映射到音乐序列会混淆学习过程，阻碍模型生成具有通用情感的音乐。本文提出EmoGen——一种情感音乐生成系统，它利用一组与情感相关的音乐属性作为情感与音乐之间的桥梁，并将生成过程分为两个阶段：基于监督聚类的“情感-属性映射”阶段和基于自监督学习的“属性-音乐生成”阶段。两个阶段均具有优势：在第一阶段，聚类中心周围的属性值代表这些样本的通用情感，有助于消除情感标签主观偏差的影响；在第二阶段，生成过程完全与情感标签解耦，从而摆脱主观偏差。主观和客观评估均表明，EmoGen在情感控制准确性和音乐质量方面分别优于先前方法，展现了我们在情感音乐生成中的优越性。EmoGen生成的音乐样本可通过此链接访问：https://ai-muzic.github.io/emogen/，代码可通过此链接获取：https://github.com/microsoft/muzic/。