Arithmetic encoders, arithmetic decoders, video encoder, video decoder, methods for encoding, methods for decoding and computer program

An arithmetic decoder for decoding a plurality of symbols having symbol values,

• wherein the arithmetic decoder is configured to derive an interval size value for an arithmetic decoding of one or more symbol values to be decoded on the basis of one or more state variable values, which represent statistics of a plurality of previously decoded symbol values,
• wherein the arithmetic decoder is configured to determine the interval size value using a base lookup table,
• wherein the arithmetic decoder is configured to determine the interval size value such that a determined interval size value is identical to an element of the base lookup table or is a rounded version of an element of the base lookup table if a probability index, which is obtained on the basis of the one or more state variable values, is within a first range, and such that a determined interval size value is obtained using a scaling and rounding of an element of the base lookup table if the probability index is within a second range;
• and
• wherein the arithmetic decoder is configured to perform the arithmetic decoding of one or more symbols using the interval size value.

A method for encoding a plurality of symbols having symbol values,

• wherein the method comprises deriving an interval size value for an arithmetic encoding of one or more symbol values to be encoded on the basis of one or more state variable values, which represent statistics of a plurality of previously encoded symbol values,
• wherein the method comprises determining the interval size value using a base lookup table,
• wherein the method comprises determining the interval size value such that a determined interval size value is identical to an element of the base lookup table or is a rounded version of an element of the base lookup table if a probability index, which is obtained on the basis of the one or more state variable values, is within a first range, and such that a determined interval size value is obtained using a scaling and rounding of an element of the base lookup table if the probability index is within a second range;
• and
• wherein the method comprises performing the arithmetic encoding of one or more symbols using the interval size value.

A method for decoding a plurality of symbols having symbol values,

• wherein the method comprises deriving an interval size value for an arithmetic decoding of one or more symbol values to be decoded on the basis of one or more state variable values, which represent statistics of a plurality of previously decoded symbol values,
• wherein the method comprises determining the interval size value using a base lookup table,
• wherein the method comprises determining the interval size value such that a determined interval size value is identical to an element of the base lookup table or is a rounded version of an element of the base lookup table if a probability index, which is obtained on the basis of the one or more state variable values, is within a first range, and such that a determined interval size value is obtained using a scaling and rounding of an element of the base lookup table if the probability index is within a second range;
• and
• wherein the method comprises performing the arithmetic decoding of one or more symbols using the interval size value.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for encoding a plurality of symbols having symbol values,

• wherein the method comprises deriving an interval size value for an arithmetic encoding of one or more symbol values to be encoded on the basis of one or more state variable values, which represent statistics of a plurality of previously encoded symbol values,
• wherein the method comprises determining the interval size value using a base lookup table,
• wherein the method comprises determining the interval size value such that a determined interval size value is identical to an element of the base lookup table or is a rounded version of an element of the base lookup table if a probability index, which is obtained on the basis of the one or more state variable values, is within a first range, and such that a determined interval size value is obtained using a scaling and rounding of an element of the base lookup table if the probability index is within a second range;
• and
• wherein the method comprises performing the arithmetic encoding of one or more symbols using the interval size value,
• when said computer program is run by a computer.

A non-transitory digital storage medium having a computer program stored thereon to perform the method for decoding a plurality of symbols having symbol values,

• wherein the method comprises deriving an interval size value for an arithmetic decoding of one or more symbol values to be decoded on the basis of one or more state variable values, which represent statistics of a plurality of previously decoded symbol values,
• wherein the method comprises determining the interval size value using a base lookup table,
• wherein the method comprises determining the interval size value such that a determined interval size value is identical to an element of the base lookup table or is a rounded version of an element of the base lookup table if a probability index, which is obtained on the basis of the one or more state variable values, is within a first range, and such that a determined interval size value is obtained using a scaling and rounding of an element of the base lookup table if the probability index is within a second range;
• and
• wherein the method comprises performing the arithmetic decoding of one or more symbols using the interval size value,
• when said computer program is run by a computer.