Bit stream signal feature detection in a signal processing system

Abstract

A multi-standard start code detector system receives an incoming compressed video bit stream. The compressed video bit stream includes start codes interspersed between variable length bit streams. Assuming error-free useful data, zero stuffing bits preceding a next start code are rapidly discarded on a bit group-wise basis. A group of current bits are processed by comparing them to a start code feature pattern. If a match is not detected, the entire group of bits is concurrently replaced by a next group. However, because the zero stuffing bits are of variable length, the exact position of the start code pattern is unknown. Preceding each replacement operation, the next group of bits is processed to predetect a start code feature. Upon predetecting a start code feature, the replacement operation is modified to ensure that a group of current data bits will include the start code feature pattern. This allows the number of searched for patterns to be reduced and streamlines the comparison operation. Additionally, the multi-standard start code detector system implements an error handling operation that effectively searches and discards bits on a group-wise basis. The error handling operation compares a group of current data to a pattern known to subsequently occur and that is not included in useful data. In one embodiment, the error handling operation compares the bit group to a zero stuffing bit pattern. Upon detection of the zero stuffing bits, the error handling operation proceeds in accordance with the start code feature detection operation.