Device and method for entropy encoding of information words and device and method for decoding entropy-encoded information words

A device for decoding of information words that are entropy-encoded using reversible code words, said information words being present in the form of a data stream and an escape region, the data stream comprising only reversible code words for information words with a region of information words and the escape region comprising non-reversible code words for additional values representing information words outside the region of information words, there being always assigned one code word of the escape region to one predetermined code word of the data stream each, said device comprising:

• means for detecting a reversible code word from the data stream;
• means for assigning a specific information word to the code word detected from the data stream, on the basis of a code table;
• means for detecting a predetermined reversible code word in the data stream;
• means for ascertaining outside of said region on the basis of the predetermined code a non-reversible variable length code word in the escape region, which is assigned to the predetermined reversible code word detected from the data stream, for assigning an additional value to the non-reversible variable length code word on the basis of an escape table for the non-reversible variable length code words, and for ascertaining an information word outside of the region of information words on the basis of the additional value.

A method for entropy encoding of information words, comprising:

• assigning a reversible code word from a group of reversible code words to an information word which is located within a region of information words, the group of reversible code words being designed such that, for each information word within the region, there is provided one specific reversible code word each;
• producing a predetermined reversible code word for an information word located outside said region of information words;
• producing an additional value for the information word which is located outside said region of information words;
• producing a data stream of reversible code words comprising only reversible code words for information words within said region and comprising predetermined reversible code words for information words outside said region;
• and
• coding the additional value by assigning a non-reversible variable length code word from a group of non-reversible variable length code words to the additional value, with an escape region being produced which is separated from the data stream of reversible code words and consists of non-reversible variable length code words, there being always assigned one code word of the escape region to one of the predetermined code words of the data stream each.

A method for decoding of information words that are entropy-encoded using reversible code words, said information words being present in the form of a data stream and an escape region, the data stream comprising only reversible code words for information words within a region of information words and the escape region comprising non-reversible code words for additional values representing information words outside the region of information words, there being always assigned one code word of the escape region to one predetermined code word of the data stream each, said method comprising the following steps:

• detecting a reversible code word from the data stream;
• assigning a specific information word to the code word detected from the data stream, on the basis of a code table;
• detecting a predetermined reversible code word in the data stream;
• ascertaining a non-reversible variable length code word in the escape region, which is assigned to the predetermined reversible code word detected from the data stream;
• assigning an additional value to the non-reversible variable length code word on the basis of an escape table for the non-reversible variable length code words;
• and
• ascertaining an information word outside of the region of information words on the basis of the additional value.