Abstract: A system-on-chip (SoC) for voice and video over data network applications includes a first and a second general purpose processors and a plurality of coprocessors. The coprocessors include: a VCODEC engine for video compression/decompression, a security engine for data encryption/decryption, a network processor for processing data packets, a video scaling controller for scaling up/down video frames, and digital signal coprocessors for signal processing and audio codec. An on-chip shared memory (e.g., SRAM) is coupled to the processors and some of the coprocessors. The SoC also includes: i) a stream controller for controlling various properties of a stream buffer in the shared memory according to a user defined context; ii) a transaction management engine for managing data especially stream transactions in accordance with one or more task queues created by the processors; and iii) a bi-directional stream bus coupled to the shared memory and a plurality of peripheral controllers.