This paper explores the opportunities and challenges of supplementing television broadcast channels with additional content using IP delivery. It looks at the way in which the additional material could be resynchronised with the broadcast content and what level of accuracy is required by different types of material. It focuses on the use case of an alternative soundtrack to provide improved intelligibility for viewers who have difficulty understanding speech when presented with background sound. It then goes on to describe our demonstration system and discusses the opportunities for further research into hybrid delivery and the way it could enable a richer broadcasting landscape.