An encoder includes processing circuitry, a block memory, and a frame memory. The processing circuitry defines at least one parameter for each of plural types of segment_ids, splits an image into blocks, assigns, to each of the blocks, segment_id according to a type of the block, among the plural types of segment_ids, and sequentially encodes the blocks. In encoding the blocks, the processing circuitry identifies segment_id of a current block to be encoded, and encodes the current block using the at least one parameter defined for identified segment_id. The at least one parameter includes seg_context_idx for identifying probability information associated with context used in context-based adaptive binary arithmetic coding (CABAC).

A highly programmable data processing unit includes multiple processing units for processing streams of information, such as network packets or storage packets. The data processing unit includes one or more specialized hardware accelerators configured to perform acceleration for various data-processing functions. The data processing unit is configured to retrieve speculative probability values for range coding a plurality of bits with a single read instruction to an on-chip memory that stores a table of probability values. The data processing unit is configured to store state information used for context-coding packets of a data stream so that the state information is available after switching between data streams.

Decomposing a value range of the respective syntax elements into a sequence of n partitions with coding the components of z laying within the respective partitions separately with at least one by VLC coding and with at least one by PIPE or entropy coding is used to greatly increase the compression efficiency at a moderate coding overhead since the coding scheme used may be better adapted to the syntax element statistics. Accordingly, syntax elements are decomposed into a respective number n of source symbols s.sub.i with i=1 . . . n, the respective number n of source symbols depending on as to which of a sequence of n partitions into which a value range of the respective syntax elements is sub-divided, a value z of the respective syntax elements falls into, so that a sum of values of the respective number of source symbols s.sub.i yields z, and, if n>1, for all i=1 . . . n1, the value of s.sub.i corresponds to a range of the i.sup.th partition.

According to the invention, there are provided sets of contexts specifically adapted to encode special coefficients of a prediction error matrix, on the basis of previously encoded values of level k. Furthermore, the number of values of levels other than 0 is explicitly encoded and numbers of appropriate contexts are selected on the basis of the number of spectral coefficients other than 0.

The present invention is a variable length coding method for coding coefficients in each block which are obtained by performing frequency transformation on picture data of a moving picture per block having a predetermined size, and comprises: a coefficient scanning step of scanning the coefficients in the block in a predetermined order; and a coding step of coding the coefficients scanned in the coefficient scanning step into variable length codes in a predetermined order by switching a plurality of tables to be used for coding. Here, a direction of switching between the tables may be one-directional. Also, the coding may be non-arithmetic coding.

Provided is, for example, an arithmetic coding device capable of coding, at high speed, a symbol sequence including a context symbol and a bypass symbol. The arithmetic coding device updates an occurrence probability of a context symbol for a symbol sequence including the context symbol and a bypass symbol; updates a numerical range for the symbol sequence based on the updated occurrence probability; updates the updated numerical range based on a predetermined probability, the numerical range being a basis of an arithmetic code, the numerical range being updated in accordance with the occurrence probability of the context symbol and the predetermined probability for the bypass symbol; and generates an arithmetic code of the symbol sequence based on the updated numerical range in accordance with a procedure of generating the arithmetic code.

A frame coding unit generates individual picture signal information from a moving picture signal, and outputs a frame code value which is a numeric value to be obtained as a result of coding picture signal information of each frame. A variable length coding unit decomposes the frame code value into unit frame code values which are basic units of coding, converts the unit frame code values into frame code words using only a single code table, and constructs a frame stream by combining the converted frame code words. A multiplexing unit multiplexes a header stream which is constructed through a method equivalent to a conventional method and the frame stream, and constructs a picture coded signal.

Methods and systems for encoding of integers are discussed. For example, various methods and systems may utilize Huffman coding, Tunstall coding, Arithmetic Coding, LZ77 coding, LZ78 coding, LW coding, or Shannon Fano Elias coding to encode the integers.

A frame coding unit generates individual picture signal information from a moving picture signal, and outputs a frame code value which is a numeric value to be obtained as a result of coding picture signal information of each frame. A variable length coding unit decomposes the frame code value into unit frame code values which are basic units of coding, converts the unit frame code values into frame code words using only a single code table, and constructs a frame stream by combining the converted frame code words. A multiplexing unit multiplexes a header stream which is constructed through a method equivalent to a conventional method and the frame stream, and constructs a picture coded signal.

Methods of encoding and decoding data in which some data symbols are entropy coded and some data symbols are bypass coded. The encoder separates the coded symbols into an entropy coded stream and a bypass coded stream. The streams are packaged in a data unit that has a payload structured to contain one of the streams in forward order and the other stream in reverse order, with the reverse order stream aligned with the end of the data unit. In this manner, at the decoder, the decoder may begin decoding the forward order stream from its beginning and may also begin decoding the reverse order stream from its beginning at the end of the data unit by extracting symbols in reverse order. The data unit does not need to signal the length of the streams. The decoder determines the length of the data unit from explicit or implicit signaling.