Methods of coding and decoding moving-picture signals, using self-resynchronizing variable-length codes
First Claim
1. A method of coding a source signal representing a moving picture, comprising the steps of:
- (a) generating a series of digital information items of at least three different types from said source signal, said different types of digital information item indicating information about the moving picture;
(b) coding the digital information items of at least one of said types according to at least one fixed-length coding rule, thereby generating fixed-length codewords; and
(c) coding the digital information items of all other of said types, comprising at least two of said types, according to a single, self-resynchronizing, variable-length coding rule, thereby generating variable-length codewords.
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Abstract
A coded moving-picture signal consists of segments, each having a start code, header information, and coded picture data. The picture data are coded according to a self-resynchronizing variable-length coding rule. During decoding, if an error is recognized, this coding rule is applied in order to resynchronize; the coded data from the resynchronization point up to the next start code are stored in a memory; then the memory contents are decoded. According to a first aspect of the invention, the header information is coded according to the same variable-length coding rule, except for group header information appearing immediately after the start code. According to a second aspect of the invention, the start code is followed by all the header information in the segment, then by all the coded picture data in the segment.
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Citations
35 Claims
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1. A method of coding a source signal representing a moving picture, comprising the steps of:
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(a) generating a series of digital information items of at least three different types from said source signal, said different types of digital information item indicating information about the moving picture; (b) coding the digital information items of at least one of said types according to at least one fixed-length coding rule, thereby generating fixed-length codewords; and (c) coding the digital information items of all other of said types, comprising at least two of said types, according to a single, self-resynchronizing, variable-length coding rule, thereby generating variable-length codewords. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of coding a source signal representing a moving picture, said source signal having parts representing different picture areas and said picture areas being orginized into groups, said method comprising, for each group among said groups, the steps of:
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generating a start code for said group; generating, for each picture area in said group, header information designating a picture area type and designating whether coded picture data are present for said picture area, said picture area type indicating a coding format of said picture area; generating coded picture data for those picture areas designated in said header information as having coded picture data present, using a self-resynchronizing variable-length coding rule; and outputting said start code, followed by said header information for all picture areas in said group, then followed by said coded picture data. - View Dependent Claims (10, 11, 12, 13)
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14. A method of decoding a coded signal containing both fixed-length and variable-length codewords, in which all of said variable-length codewords are coded according to a single self-resynchronizing coding rule, and in which, among said codewords, there are start codes that begin segments of said coded signal pertaining to respective groups of picture areas, comprising the steps of:
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detecting one start code among said start codes; decoding codewords following said one start code; checking for errors in the codewords thus decoded; attempting to resynchronize according to said signal self-resynchronizing coding rule, if an error is recognized; storing subsequent codewords in a memory until a next start code is detected when resynchronization occurs after an error; and decoding contents of said memory. - View Dependent Claims (15, 16, 17)
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18. A method of decoding a coded signal containing start codes, header information, and coded picture data, each of said start codes being followed by header information pertaining to one group of picture areas and to individual picture areas in said group of picture areas, then by coded picture data pertaining to the same group of picture areas, and said coded picture data being coded according to a self-resynchronizing variable-length coding rule, said method comprising the steps of:
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detecting one of said start codes; decoding the header information following said one of said start codes; storing the header information thus decoded in a memory; decoding said coded picture data while referring to the header information stored in said memory; checking for errors in the header information and coded picture data thus decoded; attempting to resynchronize according to said variable-length coding rule, if an error is recognized; storing subsequent coded picture data in said memory until a next start code is detected when resynchronization occurs after an error; and decoding the coded picture data stored in said memory while referring to the header information stored in said memory. - View Dependent Claims (19, 20, 21)
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22. A video coder for coding a video signal representing a moving picture, comprising:
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a source coder for receiving said video signal and generating a series of fixed-length digital information items of at least two different types, said different types of digital information items indicating information about the moving picture; and a video multiplex coder coupled to said source coder, for coding at least two of said different types of said digital information items according to a single self-resynchronizing variable-length coding rule. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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30. A video decoder for decoding a coded video signal representing a moving picture, said coded video signal being segmented by start codes, said video decoder comprising:
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a video multiplex decoder having a memory, for detecting one of said start codes in said coded video signal, using a self-resynchronizing variable-length coding rule to decode at least part of said coded video signal following said start code, checking for errors, using said self-resynchronize variable-length coding rule to resynchronize following an error, storing said coded video signal in said memory after resynchronization until another one of said start codes is detected, and decoding contents of said memory after detection of said another one of said start codes; and a source decoder coupled to said video multiplex decoder, for receiving said video signal as decoded by said video multiplex decoder, and performing further decoding to generate a video signal. - View Dependent Claims (31, 32, 33, 34, 35)
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Specification