Patent ID: RE38871

Claim:
An apparatus for receiving and decoding a bit stream of data blocks, each comprising a digital coded bit sequence, which are organized in a hierarchy including a plurality of layers, each layer having associated therewith one of a plurality of layer types, wherein at least one layer of a high-order layer type is composed of at least one layer of a lower-order layer type, each of the data blocks corresponding to one of the layers and including a start code which identifies the layer type of the data block, the apparatus comprising: a layer memory for storing data indicating the layer type corresponding to the last start code received in the bit stream, the layer memory having a last layer type output, a first expected start code selector coupled to receive the last layer type output from the layer memory, the first expected start code selector selecting and generating a first expected start code selector output identifying a set of expected start codes based on the last layer type received, wherein start codes of data blocks in the high-order layers are identified as expected start codes before start codes of data blocks in the lower-order layers; start code detector, coupled to received the bit stream and the first expected start code selector output, for detecting start codes by comparing data in the bit stream with the set of expected start codes, the start code detector selecting one of the expected start codes as a detected start code, if one of the expected start codes is similar to data in the bit stream, the start code detector having a start code detector output which identifies the detected start code and its corresponding layer type; means responsive to the start code detector output for updating the layer memory with data indicating the layer type corresponding to the detected start code; and a block data decoder, responsive to the detected start code output from the start code detector, for decoding the data block corresponding to the detected start code.