Client based synchronization control of coded data streams

In a multimedia news on demand application, the delivery of multiple streams of data over a network will introduce inevitable delays and delay variations that disrupt both inter- and intra-media synchronization. Therefore, a complete stream synchronization protocol must be specified and tested to ensure proper rendering of the multimedia presentation at the client. In such a protocol, special treatment should be considered for time dependent coded data streams due to the presence of a hardware/software decoding entity at the client. We propose a client based control scheme using buffer occupancy as its main parameter. The control scheme uses time contraction and expansion concepts to: avoid data overflow or underflow conditions; and enforce intra-media synchrony of the data stream. We refer to such a control mechanism as the predecoder synchronization controller. We consider both motion JPEG and MPEG video bit streams and discuss the implementation and architectural constraints encountered