ImmersiaTV is a H2020 European project that targets the creation of novel forms of TV content production, delivery and consumption to enable customizable and immersive multi-screen TV experiences. The goal is not only to provide an efficient support for multi-screen scenarios, but also to achieve a seamless integration between the traditional TV content formats and consumption devices with the emerging omnidirectional ones (e.g. 360o video and spatial audio), thus opening the door to new fascinating scenarios. This paper presents the end-to-end toolset that is being developed to overcome existing challenges, with a special focus on the building blocks that require a re-definition to meet the targeted goals. The contents that have been created and the considered pilot scenarios to demonstrate the feasibility and benefits of the project are briefly described as well. Overall, the contributions of ImmersiaTV allow providing new forms of customizable, interactive and immersive experiences across multiple devices, including main TVs, tablets, smartphones and Head Mounted Displays (HMDs).