Error recovery of corrupted MPEG-4 bitstreams using fuzzy decoding of start codes and resync markers

An error-recovering motion-picture-experts group (MPEG) decoder comprising:

• a bitstream input for receiving an MPEG bitstream, the MPEG bitstream being a sequence of video packets arranged into video object planes, each video object plane encoding an image frame of a video;
• wherein each video packet after a first video packet in a video object plane begins with a resync marker, a header, and a data field;
• wherein each video object plane begins with a start code, followed by a header and a data field for a first video packet in the video object plane;
• a start-code detector, coupled to the bitstream input, for detecting the start code at a beginning of each new video object plane;
• a resync-marker detector, coupled to the bitstream input, for detecting the resync marker at a beginning of video packets in the video object plane;
• a macroblock processor, receiving data fields from the bitstream input, for processing macroblocks in the data fields, the macroblocks representing a portion of the image frame encoded by the video object plane;
• and
• a fuzzy detector, coupled to the bitstream input, for detecting a partial match of the start code, the fuzzy detector signaling the macroblock processor to process macroblocks in the data field of a first video packet in a video object plane when the partial match is detected with a corrupted start code for the first video packet;
• whereby partial matches of the start code allow macroblocks to be processed.

An motion-picture-experts group (MPEG) bitstream decoder comprising:

• parser means for receiving a bitstream containing bit errors, the bitstream encoding compressed video arranged as video object planes each having a plurality of video packets;
• fuzzy start-code decoder means, coupled to the parser means, for detecting a fuzzy start code in the bitstream, the fuzzy start code including a set of predetermined codes that match a portion of a start code, but have bit errors that do not match other portions of the start code, the start code for marking a start of a video object plane;
• resync marker decoder means, coupled to the parser means, for detecting a resync marker in the bitstream, the resync marker for marking a beginning of a video packet;
• and
• macroblock decoder means, coupled to the parser means, for extracting video macroblocks from data fields in the bitstream;
• wherein a corrupted start code in a corrupted bitstream is detected when bit errors occur in the start code but not in the fuzzy start code portion of the start code,
• whereby the bitstream is recovered from the corrupted start code.