JpegHuffmanTable

Ecng.Drawing

Canonical JPEG Huffman codes with an eight-bit lookup and compact tables for longer prefixes.

Constructores

public JpegHuffmanTable(ReadOnlySpan<byte> counts, ReadOnlySpan<byte> symbols)

jpegHuffmanTable = JpegHuffmanTable(counts, symbols)

counts: How many codes there are of each length from 1 to 16.
symbols: The symbols, in order of their codes.

Métodos

Optimize

public static byte[] Optimize(ReadOnlySpan<int> frequencies, Span<byte> counts)

result = JpegHuffmanTable.Optimize(frequencies, counts)

Works out the table that makes a scan shortest: the more often a symbol occurs, the shorter its code (section K.2 of the standard). No code is longer than sixteen bits, and none is all ones.

frequencies: How many times each of the 256 symbols occurs; at least one of them does.
counts: Receives how many codes there are of each length from 1 to 16.

Devuelve: The symbols that occur, in order of their codes.