MPEG audio decoder for detecting and correcting irregular patterns

An MPEG audio decoder for decoding an input bit stream including a plurality of frames coded according to an MPEG audio coding method, comprising:

• frame unpacking means for unpacking header information, bit allocation information, scale-factor information, and sample data from each of said frames;
• bit allocation decoding means coupled to said frame unpacking means, for decoding said bit allocation information to obtain decoded bit allocation values;
• scale-factor decoding means coupled to said frame unpacking means, for decoding said scale-factor information to obtain decoded scale-factor values;
• inverse quantizing means coupled to said frame unpacking means, for dequantizing said sample data according to said decoded bit allocation information to obtain dequantized sample values;
• inverse normalizing means coupled to said inverse quantizing means, for denormalizing said dequantized sample values according to said decoded scale-factor values to obtain denormalized sample values;
• subband audio signal synthesizing means coupled to said inverse normalizing means, for synthesizing an output audio signal from said denormalized sample values;
• and
• irregular-pattern processing means, coupled to at least one means among said frame unpacking means, said bit allocation decoding means, said scale-factor decoding means, said inverse quantizing means, said inverse normalizing means, and said subband audio signal synthesizing means, for detecting irregular patterns in said bit allocation information, said scale-factor information or said sample data and for altering at least one entity among said decoded scale-factor values, said sample data, said dequantized sample values, and said output audio signal, when said irregular patterns are detected, thereby preventing said irregular patterns from causing defects in said output audio signal.