Almost every country in Latin America has adopted the ISDBT standard for free-to-air television broadcasting. The so-called "analogical blackout" is about to be performed, so broadcast engineers and technicians have to be prepared for such a challenging task. Key to the success of this blackout is a deep understanding of the chosen technology. In this paper we present the first open, free and fully software-based ISDB-T receiver, entirely implemented in GNU Radio. Moreover, all our blocks produce several relevant measurements. This implementation allows broadcasting professionals and researchers to get in touch with a real-time working receiver, avoiding the need of costly Digital Television equipment. Moreover, the block-based architecture of GNU Radio offers the possibility of replacing particular blocks or simulate channel conditions, in order to test different algorithms and implementations. As a toy example of the possibilities brought by our framework, we compare two OFDM synchronization methods in terms of the resulting BER in a typical scenario.