In this paper, we report on our experience in developing an SoC audio player using various open source components in both hardware and software parts as well as in the development process. The Ogg Vorbis audio decoder targeted for limited computing resource and low power consumption devices was developed on the free LEON SoC platform, which features a SPARC-V8 architecture compatible processor and AMBA bus. The decoder runs on the open source RTEMS operating system making use of the royalty-free open source Vorbis library. We also aim to illustrate the use of hardware/software co-design techniques. Therefore, in order to speed up the decoding process, after an analysis, a computing-intensive part of the decoding algorithm was selected and designed as an AMBA compatible hardware core. The demonstration prototype was built on the XESS XSV-800 prototyping board using GNU/Linux workstations as development workstations. This project shows that development of an SoC using an open source platform is viable and might be the preferred choice in the future.