With the growing complexity of new multimedia applications and the parallel execution enabled by multiprocessor architectures, quality-of-service (QoS) management for modern network-on-chip (NoC) systems becomes relevant. This paper presents an approach for efficient usage of platform resources and simultaneously controlling overall system performance, when multiple applications are active. Therefore, on top of the conventional QoS, we introduce an algorithm for setting quality levels of parallel executed applications on a multiprocessor network-on-chip. The new concept is a hierarchical system, where an application manager negotiates with the resource management to jointly optimize the quality of individual and overall application settings. The proposed QoS manager concept was successfully evaluated by an experimental set-up, employing two independent video-object decoders, a background sprite decoder from the MPEG-4 standard and an abstract audio object. This simultaneous execution of four independent applications was mapped on a simulator based on AEthereal network and eight ARM7 processors executed with a clock-cycle true simulator. The proposed distributed QoS management decreases the complexity of the overall management and improves the transparency and responsibilities in the decision taking.