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Huffman coding

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determine the character value of that particular leaf. The process continues recursively until the last leaf node is reached; at that point, the Huffman tree will thus be faithfully reconstructed. The overhead using such a method ranges from roughly 2 to 320 bytes (assuming an 8-bit alphabet). Many other techniques are possible as well. In any case, since the compressed data can include unused "trailing bits" the decompressor must be able to determine when to stop producing output. This can be accomplished by either transmitting the length of the decompressed data along with the compression model or by defining a special code symbol to signify the end of input (the latter method can adversely affect code length optimality, however).
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particular byte value). Before this can take place, however, the Huffman tree must be somehow reconstructed. In the simplest case, where character frequencies are fairly predictable, the tree can be preconstructed (and even statistically adjusted on each compression cycle) and thus reused every time, at the expense of at least some measure of compression efficiency. Otherwise, the information to reconstruct the tree must be sent a priori. A naive approach might be to prepend the frequency count of each character to the compression stream. Unfortunately, the overhead in such a case could amount to several kilobytes, so this method has little practical use. If the data is compressed using
2049: 5170: 5160: 2003:, the entropy is a measure of the smallest codeword length that is theoretically possible for the given alphabet with associated weights. In this example, the weighted average codeword length is 2.25 bits per symbol, only slightly larger than the calculated entropy of 2.205 bits per symbol. So not only is this code optimal in the sense that no other feasible code performs better, but it is very close to the theoretical limit established by Shannon. 2060: 3000:, where a 'dash' takes longer to send than a 'dot', and therefore the cost of a dash in transmission time is higher. The goal is still to minimize the weighted average codeword length, but it is no longer sufficient just to minimize the number of symbols used by the message. No algorithm is known to solve this in the same manner or with the same efficiency as conventional Huffman coding, though it has been solved by 2179:. A binary tree is generated from left to right taking the two least probable symbols and putting them together to form another equivalent symbol having a probability that equals the sum of the two symbols. The process is repeated until there is just one symbol. The tree can then be read backwards, from right to left, assigning different bits to different branches. The final Huffman code is: 370: 31: 467: 356:(sometimes called "prefix-free codes", that is, the bit string representing some particular symbol is never a prefix of the bit string representing any other symbol). Huffman coding is such a widespread method for creating prefix codes that the term "Huffman code" is widely used as a synonym for "prefix code" even when such a code is not produced by Huffman's algorithm. 2602:
approaches the entropy limit, i.e., optimal compression. However, blocking arbitrarily large groups of symbols is impractical, as the complexity of a Huffman code is linear in the number of possibilities to be encoded, a number that is exponential in the size of a block. This limits the amount of blocking that is done in practice.
2598:. Prefix codes, and thus Huffman coding in particular, tend to have inefficiency on small alphabets, where probabilities often fall between these optimal (dyadic) points. The worst case for Huffman coding can happen when the probability of the most likely symbol far exceeds 2 = 0.5, making the upper limit of inefficiency unbounded. 3345:
If weights corresponding to the alphabetically ordered inputs are in numerical order, the Huffman code has the same lengths as the optimal alphabetic code, which can be found from calculating these lengths, rendering Hu–Tucker coding unnecessary. The code resulting from numerically (re-)ordered input
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involves calculating the probabilities dynamically based on recent actual frequencies in the sequence of source symbols, and changing the coding tree structure to match the updated probability estimates. It is used rarely in practice, since the cost of updating the tree makes it slower than optimized
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There are two related approaches for getting around this particular inefficiency while still using Huffman coding. Combining a fixed number of symbols together ("blocking") often increases (and never decreases) compression. As the size of the block approaches infinity, Huffman coding theoretically
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Although both aforementioned methods can combine an arbitrary number of symbols for more efficient coding and generally adapt to the actual input statistics, arithmetic coding does so without significantly increasing its computational or algorithmic complexities (though the simplest version is slower
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is the number of bits per symbol). Another method is to simply prepend the Huffman tree, bit by bit, to the output stream. For example, assuming that the value of 0 represents a parent node and 1 a leaf node, whenever the latter is encountered the tree building routine simply reads the next 8 bits to
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Huffman tree generated from the exact frequencies of the text "this is an example of a huffman tree". Encoding the sentence with this code requires 135 (or 147) bits, as opposed to 288 (or 180) bits if 36 characters of 8 (or 5) bits were used (This assumes that the code tree structure is known to the
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and Huffman coding produce equivalent results — achieving entropy — when every symbol has a probability of the form 1/2. In other circumstances, arithmetic coding can offer better compression than Huffman coding because — intuitively — its "code words" can have effectively
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Many variations of Huffman coding exist, some of which use a Huffman-like algorithm, and others of which find optimal prefix codes (while, for example, putting different restrictions on the output). Note that, in the latter case, the method need not be Huffman-like, and, indeed, need not even be
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The process begins with the leaf nodes containing the probabilities of the symbol they represent. Then, the process takes the two nodes with smallest probability, and creates a new internal node having these two nodes as children. The weight of the new node is set to the sum of the weight of the
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Generally speaking, the process of decompression is simply a matter of translating the stream of prefix codes to individual byte values, usually by traversing the Huffman tree node by node as each bit is read from the input stream (reaching a leaf node necessarily terminates the search for that
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It is generally beneficial to minimize the variance of codeword length. For example, a communication buffer receiving Huffman-encoded data may need to be larger to deal with especially long symbols if the tree is especially unbalanced. To minimize variance, simply break ties between queues by
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BED". In steps 2 to 6, the letters are sorted by increasing frequency, and the least frequent two at each step are combined and reinserted into the list, and a partial tree is constructed. The final tree in step 6 is traversed to generate the dictionary in step 7. Step 8 uses it to encode the
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issues. Thus many technologies have historically avoided arithmetic coding in favor of Huffman and other prefix coding techniques. As of mid-2010, the most commonly used techniques for this alternative to Huffman coding have passed into the public domain as the early patents have expired.
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only optimally matches a symbol of probability 1/2 and other probabilities are not represented optimally; whereas the code word length in arithmetic coding can be made to exactly match the true probability of the symbol. This difference is especially striking for small alphabet sizes.
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and more complex than Huffman coding). Such flexibility is especially useful when input probabilities are not precisely known or vary significantly within the stream. However, Huffman coding is usually faster and arithmetic coding was historically a subject of some concern over
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Huffman's original algorithm is optimal for a symbol-by-symbol coding with a known input probability distribution, i.e., separately encoding unrelated symbols in such a data stream. However, it is not optimal when the symbol-by-symbol restriction is dropped, or when the
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of the source is 1.74 bits/symbol. If this Huffman code is used to represent the signal, then the average length is lowered to 1.85 bits/symbol; it is still far from the theoretical limit because the probabilities of the symbols are different from negative powers of
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enables one to use any kind of weights (costs, frequencies, pairs of weights, non-numerical weights) and one of many combining methods (not just addition). Such algorithms can solve other minimization problems, such as minimizing
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on the problem of finding the most efficient binary code. Huffman, unable to prove any codes were the most efficient, was about to give up and start studying for the final when he hit upon the idea of using a frequency-sorted
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children. We then apply the process again, on the new internal node and on the remaining nodes (i.e., we exclude the two leaf nodes), we repeat this process until only one node remains, which is the root of the Huffman tree.
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In the standard Huffman coding problem, it is assumed that any codeword can correspond to any input symbol. In the alphabetic version, the alphabetic order of inputs and outputs must be identical. Thus, for example,
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choosing the item in the first queue. This modification will retain the mathematical optimality of the Huffman coding while both minimizing variance and minimizing the length of the longest character code.
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is the generalization without this assumption: the letters of the encoding alphabet may have non-uniform lengths, due to characteristics of the transmission medium. An example is the encoding alphabet of
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The probabilities used can be generic ones for the application domain that are based on average experience, or they can be the actual frequencies found in the text being compressed. This requires that a
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followed by the use of prefix codes; these are often called "Huffman codes" even though most applications use pre-defined variable-length codes rather than codes designed using Huffman's algorithm.
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here is the number of symbols in the alphabet, which is typically a very small number (compared to the length of the message to be encoded); whereas complexity analysis concerns the behavior when
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Most often, the weights used in implementations of Huffman coding represent numeric probabilities, but the algorithm given above does not require this; it requires only that the weights form a
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is a variant where the goal is still to achieve a minimum weighted path length, but there is an additional restriction that the length of each codeword must be less than a given constant. The
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coding. This reflects the fact that compression is not possible with such an input, no matter what the compression method, i.e., doing nothing to the data is the optimal thing to do.
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In the standard Huffman coding problem, it is assumed that each symbol in the set that the code words are constructed from has an equal cost to transmit: a code word whose length is
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code. If this is not the case, one can always derive an equivalent code by adding extra symbols (with associated null probabilities), to make the code complete while keeping it
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Huffman coding is optimal among all methods in any case where each input symbol is a known independent and identically distributed random variable having a probability that is
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methods, more common symbols are generally represented using fewer bits than less common symbols. Huffman's method can be efficiently implemented, finding a code in time
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decoder and thus does not need to be counted as part of the transmitted information). The frequencies and codes of each character are shown in the accompanying table.
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to 1 contractor; for binary coding, this is a 2 to 1 contractor, and any sized set can form such a contractor. If the number of source words is congruent to 1 modulo
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solution to this optimal binary alphabetic problem, which has some similarities to Huffman algorithm, but is not a variation of this algorithm. A later method, the
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In general, a Huffman code need not be unique. Thus the set of Huffman codes for a given probability distribution is a non-empty subset of the codes minimizing
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table for encoding a source symbol (such as a character in a file). The algorithm derives this table from the estimated probability or frequency of occurrence (
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non-integer bit lengths, whereas code words in prefix codes such as Huffman codes can only have an integer number of bits. Therefore, a code word of length
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is optimal among prefix codes for coding run length, a fact proved via the techniques of Huffman coding. A similar approach is taken by fax machines using
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must be stored with the compressed text. See the Decompression section above for more information about the various techniques employed for this purpose.
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for that probability distribution. (However, for each minimizing codeword length assignment, there exists at least one Huffman code with those lengths.)
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Create a new internal node, with the two just-removed nodes as children (either node can be either child) and the sum of their weights as the new weight.
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node. As a common convention, bit '0' represents following the left child and bit '1' represents following the right child. A finished tree has up to
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to the number of input weights if these weights are sorted. However, although optimal among methods encoding symbols separately, Huffman coding
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The final encoding of any symbol is then read by a concatenation of the labels on the edges along the path from the root node to the symbol.
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Enqueue all leaf nodes into the first queue (by probability in increasing order so that the least likely item is in the head of the queue).
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We give an example of the result of Huffman coding for a code with five characters and given weights. We will not verify that it minimizes
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Once the Huffman tree has been generated, it is traversed to generate a dictionary which maps the symbols to binary codes as follows:
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and is often the code used in practice, due to ease of encoding/decoding. The technique for finding this code is sometimes called
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Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities.
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to develop a similar code. Building the tree from the bottom up guaranteed optimality, unlike the top-down approach of
4156: 4151: 413: 5098: 3316: 1934: 2660:-ary tree. This approach was considered by Huffman in his original paper. The same algorithm applies as for binary ( 5204: 5025: 4863: 4843: 4787: 4445: 4236: 4039: 3935: 894: 294: 3682:
Gallager, R.G.; van Voorhis, D.C. (1975). "Optimal source codes for geometrically distributed integer alphabets".
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Abrahams, J. (1997-06-11). "Code and parse trees for lossless source encoding". Written at Arlington, VA, USA.
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Visualisation of the use of Huffman coding to encode the message "A_DEAD_DAD_CEDED_A_BAD_BABE_A_BEADED_ABACA_
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node which makes it easy to read the code (in reverse) starting from a leaf node. Internal nodes contain a
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Huffman coding uses a specific method for choosing the representation for each symbol, resulting in a
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internal nodes. A Huffman tree that omits unused symbols produces the most optimal code lengths.
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For a set of symbols with a uniform probability distribution and a number of members which is a
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least probable symbols are taken together, instead of just the 2 least probable. Note that for
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Gribov, Alexander (2017-04-10). "Optimal Compression of a Polyline with Segments and Arcs".
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In many cases, time complexity is not very important in the choice of algorithm here, since
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The standard way to represent a signal made of 4 symbols is by using 2 bits/symbol, but the
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Prefix codes nevertheless remain in wide use because of their simplicity, high speed, and
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time, unlike the presorted and unsorted conventional Huffman problems, respectively.
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whose solution has been refined for the case of integer costs by Mordecai J. Golin.
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is the maximum length of a codeword. No algorithm is known to solve this problem in
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Dequeue the two nodes with the lowest weight by examining the fronts of both queues.
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The use of asymmetric numeral systems as an accurate replacement for Huffman coding
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approach very similar to that used by Huffman's algorithm. Its time complexity is
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Proceedings. Compression and Complexity of SEQUENCES 1997 (Cat. No.97TB100171)
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Remove the two nodes of highest priority (lowest probability) from the queue
2262: 466: 30: 17: 3972: 2563:, a single code may be insufficient for optimality. Other methods such as 5059: 4904: 4561: 3899:(1998), "Algorithm G (Garsia–Wachs algorithm for optimum binary trees)", 3854: 3267: 3957: 2706:−1, then the set of source words will form a proper Huffman tree. 4828: 4302: 4251: 3882: 3642:"Profile: David A. Huffman: Encoding the "Neatness" of Ones and Zeroes" 3487: 3826: 3486:. They are often used as a "back-end" to other compression methods. 4342: 2737: 2572: 2438:
The remaining node is the root node; the tree has now been generated.
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Create a leaf node for each symbol and add it to the priority queue.
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greater than 2, not all sets of source words can properly form an
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where the node with lowest probability is given highest priority:
2058: 465: 29: 2489:, the compression model can be precisely reconstructed with just 4332: 4186: 4171: 4161: 3720: 3715:. Division of Mathematics, Computer & Information Sciences, 3499: 3358:. The Huffman–Shannon–Fano code corresponding to the example is 2457:. Repeat the process at both the left child and the right child. 2449:
If node is not a leaf node, label the edge to the left child as
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The Art of Computer Programming, Vol. 3: Sorting and Searching
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Length-limited Huffman coding/minimum variance Huffman coding
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Since efficient priority queue data structures require O(log
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The remaining node is the root node and the tree is complete.
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classmates were given the choice of a term paper or a final
3532:"A Method for the Construction of Minimum-Redundancy Codes" 1215:
of the given set of weights; the result is nearly optimal.
857:{\displaystyle C\left(W\right)=(c_{1},c_{2},\dots ,c_{n})} 2269:. Initially, all nodes are leaf nodes, which contain the 3255:{\displaystyle H\left(A,C\right)=\left\{0,10,11\right\}} 3188:{\displaystyle H\left(A,C\right)=\left\{00,01,1\right\}} 3121:{\displaystyle H\left(A,C\right)=\left\{00,1,01\right\}} 3598:
Ze-Nian Li; Mark S. Drew; Jiangchuan Liu (2014-04-09).
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Enqueue the new node into the rear of the second queue.
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The output from Huffman's algorithm can be viewed as a
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In doing so, Huffman outdid Fano, who had worked with
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If the symbols are sorted by probability, there is a
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among all compression methods - it is replaced with
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Huffman coding in various languages on Rosetta Code
3939:, Second Edition. MIT Press and McGraw-Hill, 2001. 501:codeword length (equivalently, a tree with minimum 394:. Unsourced material may be challenged and removed. 333:and quickly proved this method the most efficient. 3774: 3454: 3400: 3305: 3254: 3187: 3120: 3053: 3008:Optimal alphabetic binary trees (Hu–Tucker coding) 2964: 2926: 2896: 2876: 2825: 2678: 2514: 2331: 2305: 2253: 2171: 2127: 2027: 1988: 1920: 1686:(in bits) is the weighted sum, across all symbols 1669:{\displaystyle h(a_{i})=\log _{2}{1 \over w_{i}}.} 1668: 1184: 1153: 1079: 1059: 947: 883: 864:, which is the tuple of (binary) codewords, where 856: 766: 675: 602: 582: 3905:. See also History and bibliography, pp. 453–454. 2424:While there is more than one node in the queues: 250:. The process of finding or using such a code is 3903:(2nd ed.), Addison–Wesley, pp. 451–453 3274:, the authors of the paper presenting the first 2753: 2583:, Huffman coding is equivalent to simple binary 2357:While there is more than one node in the queue: 1939: 2605:A practical alternative, in widespread use, is 2418:Start with as many leaves as there are symbols. 1989:{\displaystyle \lim _{w\to 0^{+}}w\log _{2}w=0} 3625:J. Duda, K. Tahboub, N. J. Gadil, E. J. Delp, 3988: 2833:, a problem first applied to circuit design. 2656:− 1} alphabet to encode message and build an 2410:)) method to create a Huffman tree using two 1708:, of the information content of each symbol: 948:{\displaystyle a_{i},\,i\in \{1,2,\dots ,n\}} 8: 3449: 3419: 3395: 3365: 2166: 2142: 2122: 2070: 942: 918: 761: 737: 676:{\displaystyle W=(w_{1},w_{2},\dots ,w_{n})} 583:{\displaystyle A=(a_{1},a_{2},\dots ,a_{n})} 483:A set of symbols and their weights (usually 2346:The simplest construction algorithm uses a 2237:of nodes. These can be stored in a regular 2128:{\displaystyle \{a_{1},a_{2},a_{3},a_{4}\}} 297:if a better compression ratio is required. 4894: 4742: 4551: 4396: 4017: 3995: 3981: 3973: 2567:often have better compression capability. 36: 3728: 3666: 3604:. Springer Science & Business Media. 3417: 3363: 3280: 3200: 3133: 3066: 3018: 2939: 2910: 2889: 2857: 2808: 2780: 2771: 2756: 2750: 2665: 2506: 2494: 2318: 2298: 2246: 2140: 2116: 2103: 2090: 2077: 2068: 2011: 1968: 1953: 1942: 1936: 1908: 1903: 1894: 1884: 1866: 1861: 1843: 1834: 1825: 1815: 1797: 1792: 1776: 1760: 1742: 1737: 1716: 1655: 1646: 1637: 1621: 1609: 1166: 1092: 1072: 1046: 1026: 1021: 1015: 1004: 968: 911: 902: 896: 875: 869: 845: 826: 813: 787: 730: 717: 694: 688: 664: 645: 632: 617: 595: 571: 552: 539: 524: 454:Learn how and when to remove this message 3128:, but instead should be assigned either 2993:Huffman coding with unequal letter costs 2977:Huffman coding with unequal letter costs 2446:Start with current node set to the root. 2180: 2047: 1217: 3821:(5) (published 1998-09-01): 1770–1781. 3815:IEEE Transactions on Information Theory 3685:IEEE Transactions on Information Theory 3519: 2561:independent and identically distributed 2559:are unknown. Also, if symbols are not 2550:Arithmetic coding § Huffman coding 2387:−1 nodes, this algorithm operates in O( 2063:A source generates 4 different symbols 590:, which is the symbol alphabet of size 3781:IRE Transactions on Information Theory 3571:"On the construction of Huffman trees" 3054:{\displaystyle A=\left\{a,b,c\right\}} 2379:) time per insertion, and a tree with 3963:Huffman codes (python implementation) 2172:{\displaystyle \{0.4;0.35;0.2;0.05\}} 7: 3455:{\displaystyle \{110,111,00,01,10\}} 3401:{\displaystyle \{000,001,01,10,11\}} 1383:Contribution to weighted path length 1204:over all codes, but we will compute 1067:be the weighted path length of code 392:adding citations to reliable sources 3863:SIAM Journal on Applied Mathematics 3806:Golin, Mordekai J. (January 1998). 2453:and the edge to the right child as 2985:digits will always have a cost of 2848:solves this problem with a simple 2796: 2793: 2790: 2787: 2784: 2781: 2233:The technique works by creating a 503:weighted path length from the root 497:(a set of codewords) with minimum 25: 3968:A visualization of Huffman coding 3947:. Section 16.3, pp. 385–392. 3630:, Picture Coding Symposium, 2015. 5169: 5168: 5159: 5158: 368: 242:is a particular type of optimal 5210:Lossless compression algorithms 2001:Shannon's source coding theorem 1185:{\displaystyle T\left(W\right)} 379:needs additional citations for 286: 3300: 3285: 2959: 2944: 2921: 2915: 2871: 2862: 2826:{\displaystyle \max _{i}\left} 2652:algorithm uses the {0, 1,..., 2366:Add the new node to the queue. 2022: 2016: 1946: 1782: 1769: 1727: 1721: 1627: 1614: 851: 806: 670: 625: 577: 532: 1: 3494:'s algorithm) and multimedia 2842:Length-limited Huffman coding 1601:with non-null probability is 1468:Information content (in bits) 3262:. This is also known as the 2515:{\displaystyle B\cdot 2^{B}} 1551: 1548: 1545: 1542: 1539: 1536: 1502: 1499: 1496: 1493: 1490: 1487: 1462: 1459: 1456: 1453: 1450: 1447: 1423: 1420: 1417: 1414: 1411: 1408: 1377: 1374: 1371: 1368: 1365: 1339: 1334: 1329: 1324: 1319: 1294: 1291: 1288: 1285: 1282: 1279: 1257: 1254: 1251: 1248: 1245: 254:, an algorithm developed by 3506:have a front-end model and 3352:Huffman–Shannon–Fano coding 3061:could not be assigned code 2522:bits of information (where 1569:, meaning that the code is 470:Constructing a Huffman Tree 5233: 5050:Compressed data structures 4372:RLE + BWT + MTF + Huffman 4040:Asymmetric numeral systems 3936:Introduction to Algorithms 3739:10.1109/SEQUEN.1997.666911 3601:Fundamentals of Multimedia 3553:10.1109/JRPROC.1952.273898 3338: 3335:The canonical Huffman code 3306:{\displaystyle O(n\log n)} 2965:{\displaystyle O(n\log n)} 2742:Huffman template algorithm 2729:Huffman template algorithm 2723:adaptive arithmetic coding 2557:probability mass functions 2547: 2399:is the number of symbols. 2289:and an optional link to a 1697:with non-zero probability 1590:, the information content 295:asymmetric numeral systems 246:that is commonly used for 27:Technique to compress data 5154: 4409:Discrete cosine transform 4339:LZ77 + Huffman + context 2686:) codes, except that the 2261:. A node can be either a 1594:(in bits) of each symbol 1435: 1350:Codeword length (in bits) 1344: 1299: 1220: 248:lossless data compression 5114:Smallest grammar problem 3793:10.1109/TIT.1961.1057615 3717:Office of Naval Research 3698:10.1109/TIT.1975.1055357 3346:is sometimes called the 2472:grows to be very large. 5055:Compressed suffix array 4604:Nyquist–Shannon theorem 3484:lack of patent coverage 2846:package-merge algorithm 2717:adaptive Huffman coding 2710:Adaptive Huffman coding 2619:modified Huffman coding 1508:Contribution to entropy 495:prefix-free binary code 3540:Proceedings of the IRE 3456: 3410:canonical Huffman code 3402: 3348:canonical Huffman code 3341:Canonical Huffman code 3317:Garsia–Wachs algorithm 3307: 3256: 3189: 3122: 3055: 2966: 2928: 2898: 2878: 2827: 2680: 2516: 2333: 2307: 2255: 2230: 2173: 2129: 2056: 2029: 1990: 1922: 1670: 1208:and compare it to the 1186: 1155: 1081: 1061: 1020: 949: 885: 858: 768: 677: 604: 584: 510:Formalized description 471: 227: 5084:Kolmogorov complexity 4952:Video characteristics 4329:LZ77 + Huffman + ANS 3640:Huffman, Ken (1991). 3457: 3403: 3308: 3257: 3190: 3123: 3056: 2967: 2929: 2899: 2879: 2877:{\displaystyle O(nL)} 2828: 2681: 2517: 2334: 2308: 2256: 2174: 2130: 2062: 2051: 2030: 1991: 1923: 1671: 1565:For any code that is 1187: 1156: 1082: 1062: 1000: 950: 886: 884:{\displaystyle c_{i}} 859: 769: 678: 605: 585: 469: 287:is not always optimal 33: 5174:Compression software 4768:Compression artifact 4724:Psychoacoustic model 3923:Charles E. Leiserson 3723:. pp. 145–171. 3416: 3362: 3279: 3199: 3132: 3065: 3017: 2938: 2927:{\displaystyle O(n)} 2909: 2888: 2856: 2749: 2664: 2493: 2317: 2297: 2245: 2139: 2067: 2028:{\displaystyle L(C)} 2010: 1999:As a consequence of 1935: 1715: 1608: 1165: 1091: 1071: 967: 895: 891:is the codeword for 868: 786: 687: 616: 594: 523: 475:Informal description 388:improve this article 271:variable-length code 5164:Compression formats 4803:Texture compression 4798:Standard test image 4614:Silence compression 3647:Scientific American 3356:Shannon–Fano coding 3329:binary search trees 2714:A variation called 2679:{\displaystyle n=2} 2641:-ary Huffman coding 2611:Bernoulli processes 2607:run-length encoding 2332:{\displaystyle n-1} 1572:uniquely decodeable 342:Shannon–Fano coding 5072:Information theory 4927:Display resolution 4753:Chroma subsampling 4142:Byte pair encoding 4087:Shannon–Fano–Elias 3787:(1). IEEE: 27–38. 3452: 3398: 3303: 3252: 3185: 3118: 3051: 2962: 2924: 2894: 2874: 2823: 2761: 2738:commutative monoid 2676: 2512: 2487:canonical encoding 2329: 2303: 2251: 2231: 2169: 2125: 2057: 2025: 1986: 1960: 1918: 1879: 1810: 1755: 1666: 1439:Probability budget 1182: 1151: 1077: 1057: 945: 881: 854: 764: 673: 600: 580: 487:to probabilities). 472: 360:Problem definition 314:information theory 236:information theory 228: 5205:1952 in computing 5187: 5186: 5036: 5035: 4986:Deblocking filter 4884: 4883: 4732: 4731: 4541: 4540: 4386: 4385: 3827:10.1109/18.705558 3795:– via IEEE. 3611:978-3-319-05290-8 3471:Arithmetic coding 3325:Michelle L. Wachs 2897:{\displaystyle L} 2752: 2565:arithmetic coding 2306:{\displaystyle n} 2254:{\displaystyle n} 2223: 2222: 2135:with probability 1938: 1857: 1849: 1788: 1733: 1661: 1563: 1562: 1080:{\displaystyle C} 603:{\displaystyle n} 464: 463: 456: 438: 320:. The professor, 291:arithmetic coding 226: 225: 16:(Redirected from 5222: 5200:Data compression 5172: 5171: 5162: 5161: 4991:Lapped transform 4895: 4773:Image resolution 4758:Coding tree unit 4743: 4552: 4397: 4018: 4004:Data compression 3997: 3990: 3983: 3974: 3927:Ronald L. Rivest 3919:Thomas H. Cormen 3906: 3904: 3897:Knuth, Donald E. 3893: 3887: 3886: 3851: 3845: 3844: 3842: 3841: 3812: 3803: 3797: 3796: 3778: 3771:Karp, Richard M. 3767: 3761: 3760: 3732: 3719:(ONR). Salerno: 3708: 3702: 3701: 3679: 3673: 3672: 3670: 3658: 3652: 3651: 3637: 3631: 3622: 3616: 3615: 3595: 3589: 3588: 3586: 3585: 3575: 3567:Van Leeuwen, Jan 3563: 3557: 3556: 3547:(9): 1098–1101. 3536: 3524: 3461: 3459: 3458: 3453: 3412:, the result is 3407: 3405: 3404: 3399: 3312: 3310: 3309: 3304: 3261: 3259: 3258: 3253: 3251: 3247: 3223: 3219: 3194: 3192: 3191: 3186: 3184: 3180: 3156: 3152: 3127: 3125: 3124: 3119: 3117: 3113: 3089: 3085: 3060: 3058: 3057: 3052: 3050: 3046: 2971: 2969: 2968: 2963: 2933: 2931: 2930: 2925: 2903: 2901: 2900: 2895: 2883: 2881: 2880: 2875: 2832: 2830: 2829: 2824: 2822: 2818: 2817: 2813: 2812: 2799: 2776: 2775: 2760: 2685: 2683: 2682: 2677: 2525: 2521: 2519: 2518: 2513: 2511: 2510: 2338: 2336: 2335: 2330: 2312: 2310: 2309: 2304: 2260: 2258: 2257: 2252: 2181: 2178: 2176: 2175: 2170: 2134: 2132: 2131: 2126: 2121: 2120: 2108: 2107: 2095: 2094: 2082: 2081: 2034: 2032: 2031: 2026: 1995: 1993: 1992: 1987: 1973: 1972: 1959: 1958: 1957: 1927: 1925: 1924: 1919: 1914: 1913: 1912: 1899: 1898: 1889: 1888: 1878: 1871: 1870: 1850: 1848: 1847: 1835: 1830: 1829: 1820: 1819: 1809: 1802: 1801: 1781: 1780: 1765: 1764: 1754: 1747: 1746: 1707: 1696: 1675: 1673: 1672: 1667: 1662: 1660: 1659: 1647: 1642: 1641: 1626: 1625: 1533: 1484: 1444: 1405: 1395: 1362: 1342: 1337: 1332: 1327: 1322: 1316: 1276: 1242: 1218: 1191: 1189: 1188: 1183: 1181: 1160: 1158: 1157: 1152: 1150: 1146: 1145: 1120: 1116: 1115: 1086: 1084: 1083: 1078: 1066: 1064: 1063: 1058: 1056: 1055: 1051: 1050: 1031: 1030: 1019: 1014: 996: 992: 991: 954: 952: 951: 946: 907: 906: 890: 888: 887: 882: 880: 879: 863: 861: 860: 855: 850: 849: 831: 830: 818: 817: 802: 773: 771: 770: 765: 726: 722: 721: 699: 698: 682: 680: 679: 674: 669: 668: 650: 649: 637: 636: 609: 607: 606: 601: 589: 587: 586: 581: 576: 575: 557: 556: 544: 543: 459: 452: 448: 445: 439: 437: 403:"Huffman coding" 396: 372: 364: 307:David A. Huffman 279:entropy encoding 256:David A. Huffman 232:computer science 37: 21: 5232: 5231: 5225: 5224: 5223: 5221: 5220: 5219: 5190: 5189: 5188: 5183: 5150: 5134: 5118: 5099:Rate–distortion 5032: 4961: 4880: 4807: 4728: 4633: 4629:Sub-band coding 4537: 4462:Predictive type 4457: 4382: 4349:LZSS + Huffman 4299:LZ77 + Huffman 4288: 4198: 4134:Dictionary type 4128: 4030:Adaptive coding 4007: 4001: 3954: 3915: 3910: 3909: 3895: 3894: 3890: 3875:10.1137/0121057 3853: 3852: 3848: 3839: 3837: 3810: 3805: 3804: 3800: 3769: 3768: 3764: 3749: 3730:10.1.1.589.4726 3710: 3709: 3705: 3681: 3680: 3676: 3660: 3659: 3655: 3639: 3638: 3634: 3623: 3619: 3612: 3597: 3596: 3592: 3583: 3581: 3573: 3565: 3564: 3560: 3534: 3526: 3525: 3521: 3516: 3468: 3414: 3413: 3360: 3359: 3343: 3337: 3277: 3276: 3266:problem, after 3231: 3227: 3209: 3205: 3197: 3196: 3164: 3160: 3142: 3138: 3130: 3129: 3097: 3093: 3075: 3071: 3063: 3062: 3030: 3026: 3015: 3014: 3010: 3002:Richard M. Karp 2979: 2936: 2935: 2907: 2906: 2886: 2885: 2854: 2853: 2839: 2804: 2800: 2767: 2766: 2762: 2747: 2746: 2735:totally ordered 2731: 2712: 2662: 2661: 2643: 2632:polynomial time 2627: 2552: 2546: 2538:frequency table 2533: 2531:Main properties 2523: 2502: 2491: 2490: 2482: 2315: 2314: 2313:leaf nodes and 2295: 2294: 2287:two child nodes 2243: 2242: 2137: 2136: 2112: 2099: 2086: 2073: 2065: 2064: 2053: 2046: 2041: 2039:Basic technique 2008: 2007: 1964: 1949: 1933: 1932: 1904: 1890: 1880: 1862: 1839: 1821: 1811: 1793: 1772: 1756: 1738: 1713: 1712: 1706: 1698: 1695: 1687: 1651: 1633: 1617: 1606: 1605: 1600: 1532: 1524: 1520: 1511: 1509: 1483: 1475: 1471: 1469: 1442: 1440: 1404: 1396: 1394: 1386: 1384: 1361: 1353: 1351: 1340: 1335: 1330: 1325: 1320: 1315: 1307: 1275: 1267: 1241: 1233: 1210:Shannon entropy 1198: 1171: 1163: 1162: 1135: 1131: 1127: 1105: 1101: 1097: 1089: 1088: 1069: 1068: 1042: 1038: 1022: 981: 977: 973: 965: 964: 962: 957: 956: 898: 893: 892: 871: 866: 865: 841: 822: 809: 792: 784: 783: 781: 776: 775: 713: 709: 690: 685: 684: 660: 641: 628: 614: 613: 611: 592: 591: 567: 548: 535: 521: 520: 518: 512: 477: 460: 449: 443: 440: 397: 395: 385: 373: 362: 350: 303: 258:while he was a 28: 23: 22: 15: 12: 11: 5: 5230: 5229: 5226: 5218: 5217: 5212: 5207: 5202: 5192: 5191: 5185: 5184: 5182: 5181: 5166: 5155: 5152: 5151: 5149: 5148: 5142: 5140: 5136: 5135: 5133: 5132: 5126: 5124: 5120: 5119: 5117: 5116: 5111: 5106: 5101: 5096: 5091: 5086: 5081: 5080: 5079: 5069: 5064: 5063: 5062: 5057: 5046: 5044: 5038: 5037: 5034: 5033: 5031: 5030: 5029: 5028: 5023: 5013: 5012: 5011: 5006: 5001: 4993: 4988: 4983: 4978: 4972: 4970: 4963: 4962: 4960: 4959: 4954: 4949: 4944: 4939: 4934: 4929: 4924: 4923: 4922: 4917: 4912: 4901: 4899: 4892: 4886: 4885: 4882: 4881: 4879: 4878: 4877: 4876: 4871: 4866: 4861: 4851: 4846: 4841: 4836: 4831: 4826: 4821: 4815: 4813: 4809: 4808: 4806: 4805: 4800: 4795: 4790: 4785: 4780: 4775: 4770: 4765: 4760: 4755: 4749: 4747: 4740: 4734: 4733: 4730: 4729: 4727: 4726: 4721: 4716: 4715: 4714: 4709: 4704: 4699: 4694: 4684: 4683: 4682: 4672: 4671: 4670: 4665: 4655: 4650: 4644: 4642: 4635: 4634: 4632: 4631: 4626: 4621: 4616: 4611: 4606: 4601: 4596: 4591: 4586: 4581: 4580: 4579: 4574: 4569: 4558: 4556: 4549: 4543: 4542: 4539: 4538: 4536: 4535: 4533:Psychoacoustic 4530: 4529: 4528: 4523: 4518: 4510: 4509: 4508: 4503: 4498: 4493: 4488: 4478: 4477: 4476: 4465: 4463: 4459: 4458: 4456: 4455: 4454: 4453: 4448: 4443: 4433: 4428: 4423: 4422: 4421: 4416: 4405: 4403: 4401:Transform type 4394: 4388: 4387: 4384: 4383: 4381: 4380: 4379: 4378: 4370: 4369: 4368: 4365: 4357: 4356: 4355: 4347: 4346: 4345: 4337: 4336: 4335: 4327: 4326: 4325: 4317: 4316: 4315: 4310: 4305: 4296: 4294: 4290: 4289: 4287: 4286: 4281: 4276: 4271: 4266: 4261: 4260: 4259: 4254: 4244: 4239: 4234: 4233: 4232: 4222: 4217: 4212: 4206: 4204: 4200: 4199: 4197: 4196: 4195: 4194: 4189: 4184: 4179: 4174: 4169: 4164: 4159: 4154: 4144: 4138: 4136: 4130: 4129: 4127: 4126: 4125: 4124: 4119: 4114: 4109: 4099: 4094: 4089: 4084: 4079: 4074: 4069: 4068: 4067: 4062: 4057: 4047: 4042: 4037: 4032: 4026: 4024: 4015: 4009: 4008: 4002: 4000: 3999: 3992: 3985: 3977: 3971: 3970: 3965: 3960: 3953: 3952:External links 3950: 3949: 3948: 3931:Clifford Stein 3914: 3911: 3908: 3907: 3888: 3846: 3798: 3773:(1961-01-31). 3762: 3747: 3703: 3692:(2): 228–230. 3674: 3653: 3632: 3617: 3610: 3590: 3558: 3518: 3517: 3515: 3512: 3467: 3464: 3451: 3448: 3445: 3442: 3439: 3436: 3433: 3430: 3427: 3424: 3421: 3397: 3394: 3391: 3388: 3385: 3382: 3379: 3376: 3373: 3370: 3367: 3339:Main article: 3336: 3333: 3321:Adriano Garsia 3302: 3299: 3296: 3293: 3290: 3287: 3284: 3250: 3246: 3243: 3240: 3237: 3234: 3230: 3226: 3222: 3218: 3215: 3212: 3208: 3204: 3183: 3179: 3176: 3173: 3170: 3167: 3163: 3159: 3155: 3151: 3148: 3145: 3141: 3137: 3116: 3112: 3109: 3106: 3103: 3100: 3096: 3092: 3088: 3084: 3081: 3078: 3074: 3070: 3049: 3045: 3042: 3039: 3036: 3033: 3029: 3025: 3022: 3009: 3006: 2978: 2975: 2961: 2958: 2955: 2952: 2949: 2946: 2943: 2923: 2920: 2917: 2914: 2893: 2873: 2870: 2867: 2864: 2861: 2838: 2835: 2821: 2816: 2811: 2807: 2803: 2798: 2795: 2792: 2789: 2786: 2783: 2779: 2774: 2770: 2765: 2759: 2755: 2730: 2727: 2711: 2708: 2675: 2672: 2669: 2642: 2636: 2626: 2623: 2585:block encoding 2545: 2542: 2532: 2529: 2509: 2505: 2501: 2498: 2481: 2478: 2459: 2458: 2447: 2440: 2439: 2436: 2435: 2434: 2431: 2428: 2422: 2419: 2395:) time, where 2373: 2372: 2369: 2368: 2367: 2364: 2361: 2355: 2348:priority queue 2328: 2325: 2322: 2302: 2250: 2221: 2220: 2217: 2213: 2212: 2209: 2205: 2204: 2201: 2197: 2196: 2193: 2189: 2188: 2185: 2168: 2165: 2162: 2159: 2156: 2153: 2150: 2147: 2144: 2124: 2119: 2115: 2111: 2106: 2102: 2098: 2093: 2089: 2085: 2080: 2076: 2072: 2045: 2042: 2040: 2037: 2024: 2021: 2018: 2015: 1985: 1982: 1979: 1976: 1971: 1967: 1963: 1956: 1952: 1948: 1945: 1941: 1929: 1928: 1917: 1911: 1907: 1902: 1897: 1893: 1887: 1883: 1877: 1874: 1869: 1865: 1860: 1856: 1853: 1846: 1842: 1838: 1833: 1828: 1824: 1818: 1814: 1808: 1805: 1800: 1796: 1791: 1787: 1784: 1779: 1775: 1771: 1768: 1763: 1759: 1753: 1750: 1745: 1741: 1736: 1732: 1729: 1726: 1723: 1720: 1702: 1691: 1677: 1676: 1665: 1658: 1654: 1650: 1645: 1640: 1636: 1632: 1629: 1624: 1620: 1616: 1613: 1598: 1588:Shannon (1948) 1586:As defined by 1561: 1560: 1550: 1547: 1544: 1541: 1538: 1535: 1528: 1522: 1516: 1505: 1504: 1501: 1498: 1495: 1492: 1489: 1486: 1479: 1473: 1465: 1464: 1461: 1458: 1455: 1452: 1449: 1446: 1437: 1433: 1432: 1422: 1419: 1416: 1413: 1410: 1407: 1400: 1390: 1380: 1379: 1376: 1373: 1370: 1367: 1364: 1357: 1347: 1346: 1343: 1338: 1333: 1328: 1323: 1318: 1311: 1304: 1297: 1296: 1293: 1290: 1287: 1284: 1281: 1278: 1271: 1263: 1262: 1259: 1256: 1253: 1250: 1247: 1244: 1237: 1230: 1197: 1194: 1180: 1177: 1174: 1170: 1149: 1144: 1141: 1138: 1134: 1130: 1126: 1123: 1119: 1114: 1111: 1108: 1104: 1100: 1096: 1076: 1054: 1049: 1045: 1041: 1037: 1034: 1029: 1025: 1018: 1013: 1010: 1007: 1003: 999: 995: 990: 987: 984: 980: 976: 972: 944: 941: 938: 935: 932: 929: 926: 923: 920: 917: 914: 910: 905: 901: 878: 874: 853: 848: 844: 840: 837: 834: 829: 825: 821: 816: 812: 808: 805: 801: 798: 795: 791: 763: 760: 757: 754: 751: 748: 745: 742: 739: 736: 733: 729: 725: 720: 716: 712: 708: 705: 702: 697: 693: 672: 667: 663: 659: 656: 653: 648: 644: 640: 635: 631: 627: 624: 621: 599: 579: 574: 570: 566: 563: 560: 555: 551: 547: 542: 538: 534: 531: 528: 511: 508: 507: 506: 491: 488: 481: 476: 473: 462: 461: 376: 374: 367: 361: 358: 349: 346: 338:Claude Shannon 322:Robert M. Fano 302: 299: 252:Huffman coding 224: 223: 220: 217: 213: 212: 209: 206: 202: 201: 198: 195: 191: 190: 187: 184: 180: 179: 176: 173: 169: 168: 165: 162: 158: 157: 154: 151: 147: 146: 143: 140: 136: 135: 132: 129: 125: 124: 121: 118: 114: 113: 110: 107: 103: 102: 99: 96: 92: 91: 88: 85: 81: 80: 77: 74: 70: 69: 66: 63: 59: 58: 55: 52: 48: 47: 44: 41: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 5228: 5227: 5216: 5213: 5211: 5208: 5206: 5203: 5201: 5198: 5197: 5195: 5179: 5175: 5167: 5165: 5157: 5156: 5153: 5147: 5144: 5143: 5141: 5137: 5131: 5128: 5127: 5125: 5121: 5115: 5112: 5110: 5107: 5105: 5102: 5100: 5097: 5095: 5092: 5090: 5087: 5085: 5082: 5078: 5075: 5074: 5073: 5070: 5068: 5065: 5061: 5058: 5056: 5053: 5052: 5051: 5048: 5047: 5045: 5043: 5039: 5027: 5024: 5022: 5019: 5018: 5017: 5014: 5010: 5007: 5005: 5002: 5000: 4997: 4996: 4994: 4992: 4989: 4987: 4984: 4982: 4979: 4977: 4974: 4973: 4971: 4968: 4964: 4958: 4957:Video quality 4955: 4953: 4950: 4948: 4945: 4943: 4940: 4938: 4935: 4933: 4930: 4928: 4925: 4921: 4918: 4916: 4913: 4911: 4908: 4907: 4906: 4903: 4902: 4900: 4896: 4893: 4891: 4887: 4875: 4872: 4870: 4867: 4865: 4862: 4860: 4857: 4856: 4855: 4852: 4850: 4847: 4845: 4842: 4840: 4837: 4835: 4832: 4830: 4827: 4825: 4822: 4820: 4817: 4816: 4814: 4810: 4804: 4801: 4799: 4796: 4794: 4791: 4789: 4786: 4784: 4781: 4779: 4776: 4774: 4771: 4769: 4766: 4764: 4761: 4759: 4756: 4754: 4751: 4750: 4748: 4744: 4741: 4739: 4735: 4725: 4722: 4720: 4717: 4713: 4710: 4708: 4705: 4703: 4700: 4698: 4695: 4693: 4690: 4689: 4688: 4685: 4681: 4678: 4677: 4676: 4673: 4669: 4666: 4664: 4661: 4660: 4659: 4656: 4654: 4651: 4649: 4646: 4645: 4643: 4640: 4636: 4630: 4627: 4625: 4624:Speech coding 4622: 4620: 4619:Sound quality 4617: 4615: 4612: 4610: 4607: 4605: 4602: 4600: 4597: 4595: 4594:Dynamic range 4592: 4590: 4587: 4585: 4582: 4578: 4575: 4573: 4570: 4568: 4565: 4564: 4563: 4560: 4559: 4557: 4553: 4550: 4548: 4544: 4534: 4531: 4527: 4524: 4522: 4519: 4517: 4514: 4513: 4511: 4507: 4504: 4502: 4499: 4497: 4494: 4492: 4489: 4487: 4484: 4483: 4482: 4479: 4475: 4472: 4471: 4470: 4467: 4466: 4464: 4460: 4452: 4449: 4447: 4444: 4442: 4439: 4438: 4437: 4434: 4432: 4429: 4427: 4424: 4420: 4417: 4415: 4412: 4411: 4410: 4407: 4406: 4404: 4402: 4398: 4395: 4393: 4389: 4377: 4374: 4373: 4371: 4366: 4364: 4361: 4360: 4359:LZ77 + Range 4358: 4354: 4351: 4350: 4348: 4344: 4341: 4340: 4338: 4334: 4331: 4330: 4328: 4324: 4321: 4320: 4318: 4314: 4311: 4309: 4306: 4304: 4301: 4300: 4298: 4297: 4295: 4291: 4285: 4282: 4280: 4277: 4275: 4272: 4270: 4267: 4265: 4262: 4258: 4255: 4253: 4250: 4249: 4248: 4245: 4243: 4240: 4238: 4235: 4231: 4228: 4227: 4226: 4223: 4221: 4218: 4216: 4213: 4211: 4208: 4207: 4205: 4201: 4193: 4190: 4188: 4185: 4183: 4180: 4178: 4175: 4173: 4170: 4168: 4165: 4163: 4160: 4158: 4155: 4153: 4150: 4149: 4148: 4145: 4143: 4140: 4139: 4137: 4135: 4131: 4123: 4120: 4118: 4115: 4113: 4110: 4108: 4105: 4104: 4103: 4100: 4098: 4095: 4093: 4090: 4088: 4085: 4083: 4080: 4078: 4075: 4073: 4070: 4066: 4063: 4061: 4058: 4056: 4053: 4052: 4051: 4048: 4046: 4043: 4041: 4038: 4036: 4033: 4031: 4028: 4027: 4025: 4023: 4019: 4016: 4014: 4010: 4005: 3998: 3993: 3991: 3986: 3984: 3979: 3978: 3975: 3969: 3966: 3964: 3961: 3959: 3956: 3955: 3951: 3946: 3945:0-262-03293-7 3942: 3938: 3937: 3932: 3928: 3924: 3920: 3917: 3916: 3912: 3902: 3898: 3892: 3889: 3884: 3880: 3876: 3872: 3868: 3864: 3860: 3859:Tucker, A. C. 3856: 3850: 3847: 3836: 3832: 3828: 3824: 3820: 3816: 3809: 3802: 3799: 3794: 3790: 3786: 3782: 3777: 3772: 3766: 3763: 3758: 3754: 3750: 3748:0-8186-8132-2 3744: 3740: 3736: 3731: 3726: 3722: 3718: 3714: 3707: 3704: 3699: 3695: 3691: 3687: 3686: 3678: 3675: 3669: 3664: 3657: 3654: 3649: 3648: 3643: 3636: 3633: 3629: 3628: 3621: 3618: 3613: 3607: 3603: 3602: 3594: 3591: 3579: 3572: 3568: 3562: 3559: 3554: 3550: 3546: 3542: 3541: 3533: 3529: 3523: 3520: 3513: 3511: 3509: 3505: 3501: 3497: 3493: 3489: 3485: 3480: 3477: 3472: 3465: 3463: 3446: 3443: 3440: 3437: 3434: 3431: 3428: 3425: 3422: 3411: 3392: 3389: 3386: 3383: 3380: 3377: 3374: 3371: 3368: 3357: 3353: 3349: 3342: 3334: 3332: 3330: 3326: 3322: 3318: 3314: 3297: 3294: 3291: 3288: 3282: 3273: 3269: 3265: 3248: 3244: 3241: 3238: 3235: 3232: 3228: 3224: 3220: 3216: 3213: 3210: 3206: 3202: 3181: 3177: 3174: 3171: 3168: 3165: 3161: 3157: 3153: 3149: 3146: 3143: 3139: 3135: 3114: 3110: 3107: 3104: 3101: 3098: 3094: 3090: 3086: 3082: 3079: 3076: 3072: 3068: 3047: 3043: 3040: 3037: 3034: 3031: 3027: 3023: 3020: 3007: 3005: 3003: 2999: 2994: 2990: 2988: 2984: 2976: 2974: 2972: 2956: 2953: 2950: 2947: 2941: 2918: 2912: 2891: 2868: 2865: 2859: 2851: 2847: 2843: 2836: 2834: 2819: 2814: 2809: 2805: 2801: 2777: 2772: 2768: 2763: 2757: 2743: 2739: 2736: 2728: 2726: 2724: 2719: 2718: 2709: 2707: 2705: 2701: 2697: 2693: 2689: 2673: 2670: 2667: 2659: 2655: 2651: 2649: 2640: 2637: 2635: 2633: 2624: 2622: 2620: 2616: 2615:Golomb coding 2612: 2608: 2603: 2599: 2597: 2592: 2590: 2586: 2582: 2577: 2574: 2568: 2566: 2562: 2558: 2551: 2543: 2541: 2539: 2530: 2528: 2507: 2503: 2499: 2496: 2488: 2480:Decompression 2479: 2477: 2473: 2471: 2467: 2462: 2456: 2452: 2448: 2445: 2444: 2443: 2437: 2432: 2429: 2426: 2425: 2423: 2420: 2417: 2416: 2415: 2413: 2409: 2405: 2400: 2398: 2394: 2390: 2386: 2382: 2378: 2370: 2365: 2362: 2359: 2358: 2356: 2353: 2352: 2351: 2349: 2344: 2340: 2326: 2323: 2320: 2300: 2292: 2288: 2284: 2280: 2276: 2272: 2268: 2267:internal node 2264: 2248: 2240: 2236: 2227: 2218: 2215: 2214: 2210: 2207: 2206: 2202: 2199: 2198: 2194: 2191: 2190: 2186: 2183: 2182: 2163: 2160: 2157: 2154: 2151: 2148: 2145: 2117: 2113: 2109: 2104: 2100: 2096: 2091: 2087: 2083: 2078: 2074: 2061: 2050: 2043: 2038: 2036: 2019: 2013: 2004: 2002: 1997: 1983: 1980: 1977: 1974: 1969: 1965: 1961: 1954: 1950: 1943: 1915: 1909: 1905: 1900: 1895: 1891: 1885: 1881: 1875: 1872: 1867: 1863: 1858: 1854: 1851: 1844: 1840: 1836: 1831: 1826: 1822: 1816: 1812: 1806: 1803: 1798: 1794: 1789: 1785: 1777: 1773: 1766: 1761: 1757: 1751: 1748: 1743: 1739: 1734: 1730: 1724: 1718: 1711: 1710: 1709: 1705: 1701: 1694: 1690: 1685: 1682: 1663: 1656: 1652: 1648: 1643: 1638: 1634: 1630: 1622: 1618: 1611: 1604: 1603: 1602: 1597: 1593: 1589: 1584: 1582: 1578: 1574: 1573: 1568: 1558: 1554: 1531: 1527: 1519: 1515: 1507: 1506: 1482: 1478: 1467: 1466: 1438: 1434: 1430: 1426: 1403: 1399: 1393: 1389: 1382: 1381: 1360: 1356: 1349: 1348: 1314: 1310: 1305: 1303: 1298: 1274: 1270: 1265: 1264: 1260: 1240: 1236: 1231: 1228: 1224: 1219: 1216: 1214: 1211: 1207: 1203: 1195: 1193: 1178: 1175: 1172: 1168: 1161:for any code 1147: 1142: 1139: 1136: 1132: 1128: 1124: 1121: 1117: 1112: 1109: 1106: 1102: 1098: 1094: 1087:. Condition: 1074: 1052: 1047: 1043: 1039: 1035: 1032: 1027: 1023: 1016: 1011: 1008: 1005: 1001: 997: 993: 988: 985: 982: 978: 974: 970: 960: 939: 936: 933: 930: 927: 924: 921: 915: 912: 908: 903: 899: 876: 872: 846: 842: 838: 835: 832: 827: 823: 819: 814: 810: 803: 799: 796: 793: 789: 779: 758: 755: 752: 749: 746: 743: 740: 734: 731: 727: 723: 718: 714: 710: 706: 703: 700: 695: 691: 665: 661: 657: 654: 651: 646: 642: 638: 633: 629: 622: 619: 597: 572: 568: 564: 561: 558: 553: 549: 545: 540: 536: 529: 526: 516: 509: 504: 500: 496: 492: 489: 486: 482: 479: 478: 474: 468: 458: 455: 447: 444:December 2021 436: 433: 429: 426: 422: 419: 415: 412: 408: 405: â€“  404: 400: 399:Find sources: 393: 389: 383: 382: 377:This article 375: 371: 366: 365: 359: 357: 355: 347: 345: 343: 339: 334: 332: 327: 324:, assigned a 323: 319: 315: 312: 308: 300: 298: 296: 292: 288: 284: 280: 276: 272: 267: 265: 261: 257: 253: 249: 245: 241: 237: 233: 221: 218: 215: 214: 210: 207: 204: 203: 199: 196: 193: 192: 188: 185: 182: 181: 177: 174: 171: 170: 166: 163: 160: 159: 155: 152: 149: 148: 144: 141: 138: 137: 133: 130: 127: 126: 122: 119: 116: 115: 111: 108: 105: 104: 100: 97: 94: 93: 89: 86: 83: 82: 78: 75: 72: 71: 67: 64: 61: 60: 56: 53: 50: 49: 45: 42: 39: 38: 32: 19: 5215:Binary trees 5130:Hutter Prize 5094:Quantization 4999:Compensation 4793:Quantization 4516:Compensation 4082:Shannon–Fano 4049: 4022:Entropy type 3934: 3913:Bibliography 3900: 3891: 3866: 3862: 3849: 3838:. Retrieved 3818: 3814: 3801: 3784: 3780: 3765: 3712: 3706: 3689: 3683: 3677: 3656: 3645: 3635: 3626: 3620: 3600: 3593: 3582:. Retrieved 3577: 3561: 3544: 3538: 3522: 3508:quantization 3481: 3475: 3469: 3466:Applications 3409: 3351: 3347: 3344: 3263: 3011: 2992: 2991: 2986: 2982: 2980: 2841: 2840: 2741: 2732: 2715: 2713: 2703: 2699: 2695: 2691: 2687: 2657: 2653: 2650:-ary Huffman 2647: 2646: 2644: 2638: 2628: 2604: 2600: 2593: 2581:power of two 2578: 2569: 2553: 2534: 2483: 2474: 2469: 2465: 2463: 2460: 2454: 2450: 2441: 2407: 2401: 2396: 2392: 2388: 2384: 2383:leaves has 2 2380: 2376: 2374: 2345: 2341: 2290: 2286: 2282: 2278: 2274: 2273:itself, the 2270: 2232: 2005: 1998: 1930: 1703: 1699: 1692: 1688: 1683: 1678: 1595: 1591: 1585: 1580: 1576: 1571: 1566: 1564: 1556: 1552: 1529: 1525: 1517: 1513: 1480: 1476: 1428: 1424: 1401: 1397: 1391: 1387: 1358: 1354: 1312: 1308: 1301: 1272: 1268: 1238: 1234: 1226: 1222: 1212: 1205: 1201: 1199: 958: 777: 514: 513: 485:proportional 450: 441: 431: 424: 417: 410: 398: 386:Please help 381:verification 378: 351: 335: 304: 274: 268: 251: 240:Huffman code 239: 229: 18:Huffman code 5089:Prefix code 4942:Frame types 4763:Color space 4589:Convolution 4319:LZ77 + ANS 4230:Incremental 4203:Other types 4122:Levenshtein 3528:Huffman, D. 3272:Alan Tucker 2404:linear-time 2285:, links to 2235:binary tree 2044:Compression 1436:Optimality 1306:Codewords ( 354:prefix code 348:Terminology 331:binary tree 262:student at 244:prefix code 5194:Categories 5146:Mark Adler 5104:Redundancy 5021:Daubechies 5004:Estimation 4937:Frame rate 4859:Daubechies 4819:Chain code 4778:Macroblock 4584:Companding 4521:Estimation 4441:Daubechies 4147:Lempel–Ziv 4107:Exp-Golomb 4035:Arithmetic 3869:(4): 514. 3840:2024-09-10 3668:1604.07476 3584:2014-02-20 3514:References 2998:Morse code 2625:Variations 2548:See also: 2544:Optimality 1559:) = 2.205 414:newspapers 326:term paper 5123:Community 4947:Interlace 4333:Zstandard 4112:Fibonacci 4102:Universal 4060:Canonical 3855:Hu, T. C. 3757:124587565 3725:CiteSeerX 3580:: 382–410 3295:⁡ 3264:Hu–Tucker 2954:⁡ 2500:⋅ 2324:− 2263:leaf node 1975:⁡ 1947:→ 1901:⁡ 1859:∑ 1855:− 1832:⁡ 1790:∑ 1735:∑ 1644:⁡ 1431:) = 2.25 1266:Weights ( 1122:≤ 1036:⁡ 1002:∑ 934:… 916:∈ 836:… 753:… 735:∈ 707:⁡ 655:… 562:… 519:Alphabet 305:In 1951, 5109:Symmetry 5077:Timeline 5060:FM-index 4905:Bit rate 4898:Concepts 4746:Concepts 4609:Sampling 4562:Bit rate 4555:Concepts 4257:Sequitur 4092:Tunstall 4065:Modified 4055:Adaptive 4013:Lossless 3650:: 54–58. 3569:(1976). 3530:(1952). 3498:such as 3268:T. C. Hu 2884:, where 2587:, e.g., 2055:message. 1581:biunique 1577:complete 1567:biunique 1232:Symbol ( 499:expected 309:and his 5067:Entropy 5016:Wavelet 4995:Motion 4854:Wavelet 4834:Fractal 4829:Deflate 4812:Methods 4599:Latency 4512:Motion 4436:Wavelet 4353:LHA/LZH 4303:Deflate 4252:Re-Pair 4247:Grammar 4077:Shannon 4050:Huffman 4006:methods 3883:2099603 3835:2265146 3488:Deflate 2226:entropy 1681:entropy 1503:  1463:= 1.00 1345:  1300:Output 1221:Input ( 1196:Example 428:scholar 301:History 5178:codecs 5139:People 5042:Theory 5009:Vector 4526:Vector 4343:Brotli 4293:Hybrid 4192:Snappy 4045:Golomb 3943:  3929:, and 3881:  3833:  3755:  3745:  3727:  3608:  3496:codecs 2850:greedy 2596:dyadic 2573:patent 2412:queues 2291:parent 2283:weight 2279:parent 2275:weight 2271:symbol 2265:or an 2184:Symbol 1549:0.518 1546:0.423 1543:0.521 1540:0.411 1537:0.332 1033:length 778:Output 704:weight 612:Tuple 430:  423:  416:  409:  401:  283:linear 275:weight 222:10010 211:00111 200:11000 189:10011 178:00110 167:11001 4969:parts 4967:Codec 4932:Frame 4890:Video 4874:SPIHT 4783:Pixel 4738:Image 4692:ACELP 4663:ADPCM 4653:Îź-law 4648:A-law 4641:parts 4639:Codec 4547:Audio 4486:ACELP 4474:ADPCM 4451:SPIHT 4392:Lossy 4376:bzip2 4367:LZHAM 4323:LZFSE 4225:Delta 4117:Gamma 4097:Unary 4072:Range 3879:JSTOR 3831:S2CID 3811:(PDF) 3753:S2CID 3663:arXiv 3578:ICALP 3574:(PDF) 3535:(PDF) 3492:PKZIP 3313:-time 2589:ASCII 2239:array 2187:Code 1500:1.79 1497:2.64 1494:1.74 1491:2.74 1488:3.32 1421:0.58 1418:0.32 1415:0.60 1412:0.45 1409:0.30 1292:0.29 1289:0.16 1286:0.30 1283:0.15 1280:0.10 782:Code 515:Input 480:Given 435:JSTOR 421:books 260:Sc.D. 156:0110 145:1011 134:0010 123:0111 112:1000 101:1010 90:1101 51:space 46:Code 4981:DPCM 4788:PSNR 4719:MDCT 4712:WLPC 4697:CELP 4658:DPCM 4506:WLPC 4491:CELP 4469:DPCM 4419:MDCT 4363:LZMA 4264:LDCT 4242:DPCM 4187:LZWL 4177:LZSS 4172:LZRW 4162:LZJB 3941:ISBN 3743:ISBN 3721:IEEE 3606:ISBN 3502:and 3500:JPEG 3323:and 3270:and 2645:The 2391:log 2229:two. 2219:111 2211:110 2164:0.05 2152:0.35 1873:> 1804:> 1749:> 1679:The 1485:) ≈ 1472:−log 1460:1/4 1457:1/4 1454:1/4 1451:1/8 1448:1/8 1295:= 1 1261:Sum 963:Let 959:Goal 490:Find 407:news 318:exam 238:, a 234:and 79:000 68:010 57:111 43:Freq 40:Char 5026:DWT 4976:DCT 4920:VBR 4915:CBR 4910:ABR 4869:EZW 4864:DWT 4849:RLE 4839:KLT 4824:DCT 4707:LSP 4702:LAR 4687:LPC 4680:FFT 4577:VBR 4572:CBR 4567:ABR 4501:LSP 4496:LAR 4481:LPC 4446:DWT 4431:FFT 4426:DST 4414:DCT 4313:LZS 4308:LZX 4284:RLE 4279:PPM 4274:PAQ 4269:MTF 4237:DMC 4215:CTW 4210:BWT 4182:LZW 4167:LZO 4157:LZ4 4152:842 3871:doi 3823:doi 3789:doi 3735:doi 3694:doi 3549:doi 3504:MP3 3429:111 3423:110 3375:001 3369:000 3319:of 3292:log 3195:or 2951:log 2934:or 2754:max 2406:(O( 2203:10 2158:0.2 2146:0.4 1966:log 1940:lim 1892:log 1823:log 1635:log 1521:log 1326:011 1321:010 390:by 311:MIT 293:or 264:MIT 230:In 5196:: 4844:LP 4675:FT 4668:DM 4220:CM 3933:. 3925:, 3921:, 3877:. 3867:21 3865:. 3857:; 3829:. 3819:44 3817:. 3813:. 3783:. 3779:. 3751:. 3741:. 3733:. 3690:21 3688:. 3644:. 3576:. 3545:40 3543:. 3537:. 3462:. 3447:10 3441:01 3435:00 3393:11 3387:10 3381:01 3331:. 3245:11 3239:10 3172:01 3166:00 3111:01 3099:00 2634:. 2613:, 2216:a4 2208:a3 2200:a2 2195:0 2192:a1 1583:. 1534:) 1445:) 1406:) 1378:2 1375:2 1372:2 1369:3 1366:3 1363:) 1341:10 1336:00 1331:11 1317:) 1277:) 1258:e 1255:d 1252:c 1249:b 1246:a 1243:) 1229:) 1225:, 1192:. 774:. 610:. 505:). 493:A 344:. 5180:) 5176:( 3996:e 3989:t 3982:v 3885:. 3873:: 3843:. 3825:: 3791:: 3785:7 3759:. 3737:: 3700:. 3696:: 3671:. 3665:: 3614:. 3587:. 3555:. 3551:: 3490:( 3476:k 3450:} 3444:, 3438:, 3432:, 3426:, 3420:{ 3396:} 3390:, 3384:, 3378:, 3372:, 3366:{ 3301:) 3298:n 3289:n 3286:( 3283:O 3249:} 3242:, 3236:, 3233:0 3229:{ 3225:= 3221:) 3217:C 3214:, 3211:A 3207:( 3203:H 3182:} 3178:1 3175:, 3169:, 3162:{ 3158:= 3154:) 3150:C 3147:, 3144:A 3140:( 3136:H 3115:} 3108:, 3105:1 3102:, 3095:{ 3091:= 3087:) 3083:C 3080:, 3077:A 3073:( 3069:H 3048:} 3044:c 3041:, 3038:b 3035:, 3032:a 3028:{ 3024:= 3021:A 2987:N 2983:N 2960:) 2957:n 2948:n 2945:( 2942:O 2922:) 2919:n 2916:( 2913:O 2892:L 2872:) 2869:L 2866:n 2863:( 2860:O 2820:] 2815:) 2810:i 2806:c 2802:( 2797:h 2794:t 2791:g 2788:n 2785:e 2782:l 2778:+ 2773:i 2769:w 2764:[ 2758:i 2704:n 2700:n 2696:n 2692:n 2688:n 2674:2 2671:= 2668:n 2658:n 2654:n 2648:n 2639:n 2524:B 2508:B 2504:2 2497:B 2470:n 2466:n 2455:1 2451:0 2408:n 2397:n 2393:n 2389:n 2385:n 2381:n 2377:n 2327:1 2321:n 2301:n 2249:n 2167:} 2161:; 2155:; 2149:; 2143:{ 2123:} 2118:4 2114:a 2110:, 2105:3 2101:a 2097:, 2092:2 2088:a 2084:, 2079:1 2075:a 2071:{ 2023:) 2020:C 2017:( 2014:L 1984:0 1981:= 1978:w 1970:2 1962:w 1955:+ 1951:0 1944:w 1916:. 1910:i 1906:w 1896:2 1886:i 1882:w 1876:0 1868:i 1864:w 1852:= 1845:i 1841:w 1837:1 1827:2 1817:i 1813:w 1807:0 1799:i 1795:w 1786:= 1783:) 1778:i 1774:a 1770:( 1767:h 1762:i 1758:w 1752:0 1744:i 1740:w 1731:= 1728:) 1725:A 1722:( 1719:H 1704:i 1700:w 1693:i 1689:a 1684:H 1664:. 1657:i 1653:w 1649:1 1639:2 1631:= 1628:) 1623:i 1619:a 1615:( 1612:h 1599:i 1596:a 1592:h 1557:A 1555:( 1553:H 1530:i 1526:w 1523:2 1518:i 1514:w 1512:- 1510:( 1481:i 1477:w 1474:2 1470:( 1443:2 1441:( 1429:C 1427:( 1425:L 1402:i 1398:w 1392:i 1388:l 1385:( 1359:i 1355:l 1352:( 1313:i 1309:c 1302:C 1273:i 1269:w 1239:i 1235:a 1227:W 1223:A 1213:H 1206:L 1202:L 1179:) 1176:W 1173:( 1169:T 1148:) 1143:) 1140:W 1137:( 1133:T 1129:( 1125:L 1118:) 1113:) 1110:W 1107:( 1103:C 1099:( 1095:L 1075:C 1053:) 1048:i 1044:c 1040:( 1028:i 1024:w 1017:n 1012:1 1009:= 1006:i 998:= 994:) 989:) 986:W 983:( 979:C 975:( 971:L 961:. 955:. 943:} 940:n 937:, 931:, 928:2 925:, 922:1 919:{ 913:i 909:, 904:i 900:a 877:i 873:c 852:) 847:n 843:c 839:, 833:, 828:2 824:c 820:, 815:1 811:c 807:( 804:= 800:) 797:W 794:( 790:C 780:. 762:} 759:n 756:, 750:, 747:2 744:, 741:1 738:{ 732:i 728:, 724:) 719:i 715:a 711:( 701:= 696:i 692:w 671:) 666:n 662:w 658:, 652:, 647:2 643:w 639:, 634:1 630:w 626:( 623:= 620:W 598:n 578:) 573:n 569:a 565:, 559:, 554:2 550:a 546:, 541:1 537:a 533:( 530:= 527:A 517:. 457:) 451:( 446:) 442:( 432:¡ 425:¡ 418:¡ 411:¡ 384:. 219:1 216:x 208:1 205:u 197:1 194:r 186:1 183:p 175:1 172:o 164:1 161:l 153:2 150:t 142:2 139:s 131:2 128:n 120:2 117:m 109:2 106:i 98:2 95:h 87:3 84:f 76:4 73:e 65:4 62:a 54:7 20:)

Index

Huffman code

computer science
information theory
prefix code
lossless data compression
David A. Huffman
Sc.D.
MIT
variable-length code
entropy encoding
linear
is not always optimal
arithmetic coding
asymmetric numeral systems
David A. Huffman
MIT
information theory
exam
Robert M. Fano
term paper
binary tree
Claude Shannon
Shannon–Fano coding
prefix code

verification
improve this article
adding citations to reliable sources
"Huffman coding"

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