Method for producing video coding and programme-product
According to the invention, there are provided sets of contexts specifically adapted to encode special coefficients of a prediction error matrix, on the basis of previously encoded values of level k. Furthermore, the number of values of levels other than 0 is explicitly encoded and numbers of appropriate contexts are selected on the basis of the number of spectral coefficients other than 0.
1. Method for video coding with the procedural steps:
provision of a prediction error matrix;
conversion of the prediction error matrix by coefficient sampling into a series of symbols; and
performing context-adaptive arithmetic encoding of the symbols on the basis of symbol frequencies, for which the distribution is selected depending on an already encoded symbol;
wherein:
the context-adaptive arithmetic encoding of the symbols includes, for a symbol being encoded, selecting from different predetermined distributions of symbol frequencies a particular predetermined distribution of symbol frequencies based on the symbol encoded immediately beforehand; and
the predetermined distribution of symbol frequencies indicates the likelihood of different types of symbols occurring immediately following the type of the symbol encoded immediately beforehand based on known statistical interdependencies between different types of symbols occurring in succession.
2. Method in accordance with claim 1 , in which the prediction error matrix is converted by coefficient sampling into a series of levels and lengths of zero sequences.
3. Method in accordance with claim 2 , in which the levels and lengths are represented as unary values.
4. Method in accordance with claim 2 , in which the levels are arithmetically encoded context-adaptively in each case, with the distribution of the underlying level value frequencies being selected depending on a level value encoded beforehand in each case.
5. Method in accordance with claim 2 , in which the lengths are arithmetically encoded context-adaptively in each case, with the distribution of the underlying length value frequencies being selected depending on the length value encoded beforehand in each case.
6. Method in accordance with claim 2 , in which the level values are sorted before the context-adaptive arithmetic encoding in accordance with level values.
7. Method in accordance with claim 1 , in which the number of symbols read out for coefficient sampling is encoded and transmitted.
8. Method in accordance with claim 7 , in which the selection of the distribution of symbol frequencies is undertaken depending on the number of symbols read out.
9. Computer program product which contains program code, the program code, when loaded on a processor, configure the processor to:
provide a prediction error matrix;
convert the prediction error matrix by coefficient sampling into a series of symbols; and
perform context-adaptive arithmetic encoding of the symbols on the basis of symbol frequencies, for which the distribution is selected depending on an already encoded symbol;
wherein:
the context-adaptive arithmetic encoding of the symbols includes, for a symbol being encoded, selecting from different predetermined distributions of symbol frequencies a particular predetermined distribution of symbol frequencies based on the symbol encoded immediately beforehand; and
the predetermined distribution of symbol frequencies indicates the likelihood of different types of symbols occurring immediately following the type of the symbol encoded immediately beforehand based on known statistical interdependencies between different types of symbols occurring in succession.
10. A device for video coding for a current image represented by macroblocks and part of a bit stream, the device comprising a processor and a machine-readable medium, the machine readable medium including instructions that, when loaded on the processor, configure the processor to:
provide a prediction error matrix;
convert the prediction error matrix by coefficient sampling into a series of symbols; and
perform context-adaptive arithmetic encoding of the symbols on the basis of symbol frequencies, for which the distribution is selected depending on an already encoded symbol;
wherein:
the context-adaptive arithmetic encoding of the symbols includes, for a symbol being encoded, selecting from different predetermined distributions of symbol frequencies a particular predetermined distribution of symbol frequencies based on the symbol encoded immediately beforehand; and
the predetermined distribution of symbol frequencies indicates the likelihood of different types of symbols occurring immediately following the type of the symbol encoded immediately beforehand based on known statistical interdependencies between different types of symbols occurring in succession.