Code sequence detection in a trellis decoder

Abstract

An adaptive trellis decoder seamlessly switches between multiple operational modes. The trellis decoder employs a code sequence detection system that detects codes in input interleaved packet data. The code sequence detection system also reduces the delay (latency) between the input of encoded data and the output of decoded data. The code sequence detection system processes video data in the form of groups of interleaved trellis encoded data packets and includes a traceback network that identifies a sequence of antecedent trellis states, in accordance with a state transition trellis. The traceback network identifies the antecedent states for collocated interleaved packets in response to decision data associated with trellis state transitions. Output trellis decoded data is provided in response to the identified sequence of antecedent trellis states. The decoder can also provide a plurality of trellis decoded data sequences. The decoded data sequences are provided by identifying corresponding antecedent trellis state sequences with delayed decision data in accordance with a state transition trellis. One of the decoded data sequences is identified with a pointer updated by identifying antecedent trellis states with the decision data.