Image data encoding apparatus, comprises an entropy encoder configured to selectively encode data items representing image data so as to generate encoded binarized symbols of successive output data units; the entropy encoder being configured to generate an output data stream subject to a constraint defining an upper limit to the number of binarized symbols that may be expressed by any individual output data unit relative to the size in bytes of that output data unit, in which the entropy encoder is configured to provide padding data, for each output data unit which does not meet the constraint, so as to increase the size in bytes of that output data unit in order to meet the constraint; the apparatus comprising: an attribute detector configured to detect an encoding attribute applicable to a given output data unit; and a selector configured to select, in response to the detected encoding attribute, a constraint, for use with the given output data unit, from two or more candidate constraints.

Entropy coding a sequence of symbols is described. A first probability model for entropy coding is selected. At least one symbol of the sequence is coded using a probability determined using the first probability model. The probability according to the first probability model is updated with an estimation of a second probability model to entropy code a subsequent symbol. The combination may be a fixed or adaptive combination.

A communication system includes: a transmitter including: an arithmetic decoder configured to generate an output symbol based on input bits and a symbol frequency table that sets frequencies of excluded symbols to 0 and frequencies of allowed symbols to non-zero values, the transmitter being configured to iteratively generate a sequence of restricted packets and an ending state, the sequence of restricted packets excluding instances of the one or more excluded symbols and to transmit the sequence of restricted packets and the ending state on a channel; and a receiver including: an arithmetic encoder configured to compute an output state based on an input state, an input symbol, and the symbol frequency table, the receiver being configured to: supply an ending state received from the channel and the restricted packets to the arithmetic encoder to iteratively generate a final state, and recover a bit sequence from the final state.

A system utilizing a high throughput coding mode for CABAC in HEVC is described. The system may include an electronic device configured to obtain a block of data to be encoded using an arithmetic based encoder; to generate a sequence of syntax elements using the obtained block; to compare an Absolute-3 value of the sequence or a parameter associated with the Absolute-3 value to a preset value; and to convert the Absolute-3 value to a codeword using a first code or a second code that is different than the first code, according to a result of the comparison.

The invention provides an information preserving coding method based on possibility distribution of value of a sample. The possibility distribution of value of a sample refers to evaluation of the possibility of various values of the sample. The information preserving coding method provided is more in line with the non-stationary probability property of an actual source, and a coding code length is the overhead caused by a prediction error of the possibility distribution of value of the sample. The invention further provides multiple coding methods based on possibility distribution of value of a sample. Through improving the prediction accuracy of the possibility distribution of value of the sample, the coding efficiency is greatly improved.

Some embodiments provide a method for subdividing an interval during entropy coding for a bitstream representing a set of video pictures. The method performs a bit-shifting operation on a probability estimator value. The method computes a sub-interval value by multiplying a range value representing the interval by the bit-shifted probability estimator value. The method uses the sub-interval value to update the interval.

An idea used herein is to use the same function for the dependency of the context and the dependency of the symbolization parameter on previously coded/decoded transform coefficients. Using the same function—with varying function parameter—may even be used with respect to different transform block sizes and/or frequency portions of the transform blocks in case of the transform coefficients being spatially arranged in transform blocks. A further variant of this idea is to use the same function for the dependency of a symbolization parameter on previously coded/decoded transform coefficients for different sizes of the current transform coefficient's transform block, different information component types of the current transform coefficient's transform block and/or different frequency portions the current transform coefficient is located within the transform block.

Significance flags in advanced video compression systems are coded using contexts adaptive to the last N significance flags coded taken in a scanning order. One embodiment uses the last N significance flags in scanning order as a predictor to determine which of a plurality of sets of significance flag contexts to use for coding subsequent significance flags. A second embodiment uses the last N significance flags in scanning order as a predictor in order to modulate the probability value associated with significance flag contexts that are used to code significance flags for future coding.

Image data having ultra-high definition at a high frame rate is processed to obtain image data, having a basic format, from which an image having high definition at a basic frame rate is to be obtained, image rate, having a first enhancement format, from which an image having high definition at a high frame rate is to be obtained, image data, having a second enhancement format, from which an image having ultra-high definition at a basic frame rate is to be obtained, and image data, having a third enhancement format, from which an image having ultra-high definition at a high frame rate is to be obtained. A basic video stream containing an encoded image data of the image data having the basic format, and a predetermined number of enhancement video streams containing the encoded image data of the image data having the first, second, and third enhancement formats are produced.

A device includes a first bitstream engine and a second bitstream engine. The first bitstream engine is configured to decode a first portion of a first video frame of a plurality of video frames to generate first decoded portion data. The first bitstream engine is also configured to generate synchronization information based on completion of decoding the first portion. The second bitstream engine is configured to, based on the synchronization information, initiate decoding of a second portion of a particular video frame to generate second decoded portion data. The second bitstream engine uses the first decoded portion data during decoding of the second portion of the particular video frame. The particular video frame includes the first video frame or a second video frame of the plurality of video frames.