Introducing a cross-layer interpreter for multimedia streams

In the context of multimedia and real-time systems, this article introduces a generic interpreter of QoS properties (xQoS-Interpreter) for the Application Data Units (ADUs) composing standard and proprietary multimedia streams. This approach is intended to make the QoS properties of ADUs publicly available to any mechanism of the underlying communication system. The use of this information allows for cross-layer QoS optimization of the communication services taking the actual per-packet requirements of the applications into account. A case study showing how the xQoS-Interpreter is used at transport layer to seamlessly optimize the perceived QoS of an end-to-end video transmission is presented. In this scenario, the xQoS-Interpreter is used to optimize a TCP-friendly Rate Control mechanism (TFRC) over congested wireless network services in order to demonstrate the feasibility and advantages of our approach.