Huffman encoding are defined in Annexes F, G, and H. In this Annex, the Huffman table specification is defined.
1 to 16. This is followed by a list of the 8-bit symbol values (HUFFVAL), each of which is assigned a Huffman code. The
symbol values are placed in the list in order of increasing code length. Code lengths greater than 16 bits are not allowed.
In addition, the codes shall be generated such that the all-1-bits code word of any length is reserved as a prefix for longer
code words.
symbol values) are derived from the two lists (BITS and HUFFVAL) in the interchange format. However, the way in
which these lists are generated is not specified. The lists should be generated in a manner which is consistent with the
rules for Huffman coding, and it shall observe the constraints discussed in the previous paragraph. Annex K contains an
example of a procedure for generating lists of Huffman code lengths and values which are in accord with these rules.
specified in this annex. The sole criterion for an encoder or decoder to be considered in compliance with this Specification is that it
satisfy the requirements given in clause 6 (for encoders) or clause 7 (for decoders), as determined by the compliance tests specified in
Part 2.
syntax for Huffman table specification.
(Figure C.1) generates a table of Huffman code sizes. The second procedure (Figure C.2) generates the Huffman codes
from the table built in Figure C.1. The third procedure (Figure C.3) generates the Huffman codes in symbol value order.
values to be associated with those codes as described above, two tables are generated. The HUFFSIZE table contains a list
of code lengths; the HUFFCODE table contains the Huffman codes corresponding to those lengths.