ermore, MPEG-4 offers a generic QoS descriptor for dissimilar MPEG-4 media that can be interpreted and translated into the appropriate native signaling messages of each network. End-to-end signaling of the MPEG-4 media QoS descriptors enables transport optimization in heterogeneous networks. However, the exact translations from the QoS parameters set for each media to the network QoS are left to network providers. MPEG-4 offers end users higher levels of interaction with content, and allows the author to set those limits. It also extends multimedia to new networks, such as mobile networks and others that employ lower bit rates. MPEG seeks to supersede proprietary, non-interoperable formats by providing standardized ways to represent units of aural, visual or audiovisual content, called media objects. These media objects could be recorded with a camera or microphone, or generated with a computer. MPEG describes the composition of these objects to create compound media objects that form audiovisual scenes. It multiplexes and synchronizes the data associated with media objects SO that they can be transported over network channels and provide a QoS that is appropriate for the nature of the specific media objects, and it interacts with the audiovisual scene that is generated at the receiver's end. Media objects may require streaming data that is conveyed in multiple elementary streams. Therefore, MPEG-4 defines an object descriptor that identifies all streams that are associated with one media object. This enables the handling of hierarchically encoded data, and the association of both object content and intellectual property rights information. Each stream is characterized by a set of descriptors for configuration information, (e.g., required decoder resources, or the required precision of encoded timing information). The descriptors may also describe the QoS it requests for transmission (e.g., maximum bit rate, bit error rate, or priority). MPEG-4 enables synchronization of elementary streams by time stamping indivi