The growing complexity of signal processing algorithms and platforms poses significant challenges to design methods and implementation tools. High-level dataflow programs, such as those in MPEG's RVC-CAL language, provide abstraction and the opportunity for extensive design-space exploration, but they do raise the problem of efficient automatic synthesis to hardware and software. This paper presents a tool called Xronos that efficiently synthesizes RVC-CAL programs to an RTL-level hardware description and significantly improves on previous efforts in both quality of the resulting implementation and synthesis speed. By directly supporting all the features of the RVC-CAL language, it translates unmodified standard MPEG reference code to a functioning hardware implementation. The paper describes the essential processing architecture of Xronos, the differences from other related approaches and experimental results that show Xronos to produce faster and smaller implementations, while at the same time significantly reducing synthesis times.