This paper analyses the 'test of substantiality' and the right of reproduction in the contexts of streaming and broadcasting. We discuss how the UK, EU, and Australia have interpreted the 'test of substantiality' within the right of reproduction. We argue that, in the context of streaming and broadcasting, what constitutes the 'substantial part' of digital content should be judged holistically, by adopting a case-by-case approach that balances the interests of both rights holders and end-users.