Video decoder with functions to detect and process errors in encoded video data

A video decoding apparatus for decoding encoded video data to continuously produce decoded pictures, said encoded video data including a series of pictures, with each picture including a plurality of slices, and each slice including a plurality of macroblocks, said video decoding apparatus comprising:

• a motion-vector restoring circuit for restoring data of a motion vector for each of said macroblocks;
• an error detector for checking whether each of said slices of said each picture includes an erroneous macroblock based on said restored motion vector data, said error detector performs the checking macroblock by macroblock;
• and
• an error processing circuit for replacing an erroneous macroblock with a preceding correct macroblock, wherein when a check target slice in a picture currently undergoing decoding includes an erroneous macroblock, said error processing circuit replaces said erroneous macroblock with a preceding correct macroblock, said preceding correct macroblock included in a preceding picture to be output from said video decoding apparatus prior to said picture currently undergoing decoding, and wherein a position of said preceding correct macroblock in said preceding picture corresponds to a position of said erroneous macroblock in said picture currently undergoing decoding.

A video decoding apparatus for decoding an encoded video bit stream to continuously produce decoded pictures, said encoded video bit stream including a series of pictures, with each picture including a plurality of slices, and each slice including a plurality of macroblocks, said video decoding apparatus comprising:

• a slice header detector for detecting a slice header affixed at a head of each of said slices;
• a variable length decoder for performing variable length decoding on said video bit stream based on Huffman codes, said variable length decoder supplying variable-length decoded data;
• a dequantizer for performing dequantization on said variable-length decoded data based on a quantization threshold value to produce discrete cosine transform coefficient data;
• an inverse discrete cosine transform circuit for performing an inverse discrete cosine transform on said discrete cosine transform coefficient data;
• a motion compensated prediction circuit for performing motion compensated prediction based on a processing result from said inverse discrete cosine transform circuit to produce said decoded pictures;
• a frame buffer for temporarily storing said produced decoded pictures, said motion compensated prediction circuit performing motion compensated prediction using said decoded pictures stored in said frame buffer;
• a first error detector for checking whether each of said slices of each of said pictures includes an erroneous macroblock based on said discrete cosine transform coefficient data produced by said dequantizer, said first error detector performs the checking macroblock by macroblock;
• and
• an error processing circuit for replacing an erroneous macroblock with a preceding correct macroblock using a slice header detected by said slice header detector, wherein when a check target slice in a picture currently undergoing decoding includes an erroneous macroblock, said error processing circuit replaces said erroneous macroblock with a preceding correct macroblock, said preceding correct macroblock included in a preceding decoded picture to be output from said frame buffer prior to said picture currently undergoing decoding, and wherein a position of said preceding correct macroblock in said preceding decoded picture corresponds to a position of said erroneous macroblock in said picture currently undergoing decoding.