This paper introduces the ACCompanion, an expressive accompaniment system. Similarly to a musician who accompanies a soloist playing a given musical piece, our system can produce a human-like rendition of the accompaniment part that follows the soloist's choices in terms of tempo, dynamics, and articulation. The ACCompanion works in the symbolic domain, i.e., it needs a musical instrument capable of producing and playing MIDI data, with explicitly encoded onset, offset, and pitch for each played note. We describe the components that go into such a system, from real-time score following and prediction to expressive performance generation and online adaptation to the expressive choices of the human player. Based on our experience with repeated live demonstrations in front of various audiences, we offer an analysis of the challenges of combining these components into a system that is highly reactive and precise, while still a reliable musical partner, robust to possible performance errors and responsive to expressive variations.

翻译：本文介绍了一种富有表现力的伴奏系统——ACCompanion。与为演奏特定乐曲的独奏者伴奏的音乐家类似，该系统能够以拟人化方式生成伴奏部分，跟随独奏者在速度、力度和演奏法方面的选择。ACCompanion在符号域中工作，即需要能够生成和播放MIDI数据的乐器，且每个演奏音符的起音、止音和音高均已明确编码。我们描述了构成该系统的各个组件，涵盖从实时乐谱追踪与预测、富有表现力的演奏生成，到对人类演奏者表现性选择的在线适配。基于多次面向不同观众进行现场演示的经验，我们分析了将这些组件整合为一个高反应性、高精确度系统的挑战，该系统既要成为可靠的音乐伙伴，能够鲁棒地应对可能的演奏错误，又要对表现性变化做出灵敏响应。