Editing IndexTTS2 (section)

== Development and Background ==
IndexTTS2 was developed by a team led by Siyi Zhou at Bilibili's Artificial Intelligence Platform Department in China. The project builds upon the earlier IndexTTS model, incorporating substantial improvements in duration control, emotional modeling, and speech stability. The research was published on arXiv in September 2025, with the paper titled "IndexTTS2: A Breakthrough in Emotionally Expressive and Duration-Controlled Auto-Regressive Zero-Shot Text-to-Speech."<ref>https://arxiv.org/abs/2506.21619</ref>

The development was motivated by specific limitations in existing autoregressive TTS models, particularly their inability to precisely control speech duration - a critical requirement for applications such as video dubbing that demand strict audio-visual synchronization. Additionally, the team sought to address the limited emotional expressiveness of existing systems, which are often constrained by scarce high-quality emotional training data.