Sub-band voice codec with multi-stage codebooks and redundant coding

摘要

A system comprises an audio processing tool configured to process a bit stream for an audio signal comprising a plurality of coded audio units. Each coded unit of the plurality of coded units comprises a field indicating whether the coded unit comprises main encoded information representing a segment of the audio signal; and whether the coded unit comprises redundant coded information representing the segment of the audio signal and which can be used in decoding corresponding main encoded information for the segment. Also disclosed is a method for processing an audio signal comprising at a processor of an audio processing tool, processing a bit stream for the audio signal and outputting a result. The bit stream comprises main coded information for a current frame that references a segment of a previous frame to be used in decoding the current frame; and redundant coded information for decoding the current frame, the redundant coded information comprising signal history information associated with the referenced segment of the previous frame. The audio processing tool is a real-time speech encoder and the result is encoded speech.