Analysis and design for streaming media in DySCAS
Rasmuss Graaf · 2007
This master thesis is a part of the DySCAS project at ENEA. The purpose of this thesis project is to add support for streaming media and USB support to the DySCAS demonstrator platform. To achieve this, some of the widely used middlewares available today were studied. The one that proved to be of most interest is CORBA. Although CORBA’s solution to streaming media couldn’t be used due to their use of object programming, the CORBA solution did provide some interesting thoughts regarding how the USB devices should be handled, in this case their “resource inspector” and “trading service”. Ethernet was the chosen network to support streaming media. To allow easy handling of stream there was a need to build a specific protocol. To achieve this, a number of the protocols used today were studied. The final solution is much influenced by RTP and is sent on top of UDP. Extensive studies of USB were made, in the early stages of the master thesis much effort was made to understand the concept of USB and how drivers were built. Due to the complexity of USB, building drivers were not an option. The need for host control stack and drivers led to that OSE had to be discarded and be replaced by a slimmed version of Linux. This led to that the DySCAS middleware that was heavily connected to features available in OSE Epsilon had to be migrated to Linux. To achieve this, the middleware was “lifted” and all the system calls were mapped to an equivalent call or function located in an instantiation layer.