7 results about "Variable-length code" patented technology

The invention belongs to the technical field of communication, and particularly relates to a semantic communication method combining variable length coding and constellation probabilistic shaping, which comprises the following steps of: firstly, constructing a semantic encoder based on a mask auto-encoder framework, and designing a mask rate control function through channel state information and information source characteristics so as to dynamically adjust an information source mask rate; a self-adaptive variable-length coding mechanism is realized; according to the obtained mask rate, sampling a non-masked information source unit by adopting a maximum entropy criterion so as to reserve the information amount of the information source to the maximum extent; the constellation point optimal probability is shaped and approximated to discrete two-dimensional Gaussian distribution, and an end-to-end optimization target is deduced based on variational inference; semantic feature coding distribution is constrained through layer normalization operation to approximate Gaussian prior, so that an objective function is effectively simplified; and finally, designing a quantization modulator of semantic feature-constellation point identical distribution mapping based on finite scalar quantization, and adopting a gradient straight-through estimator to solve the non-differentiable problem of the quantization process, and finally realizing end-to-end joint optimization of the system.

A data processing system is provided that includes a processing element and a storage device. The storage device stores a code portion that, when executed by the processing element, causes the data processing system to obtain a plurality of variable length codes. Each variable length code has a first portion of variable length and a second portion. The variable length codes are separated into the first portions of the variable length codes and the second portions of the variable length codes. The data processing system uses a set of control rules to form a processed stream in chunks such that for each chunk of the processed stream that contains data from the first portions of the variable length codes, the data from the first portions forms a substream within the chunk of the processed stream having a size determined according to the control rules.

Wedgelet-based coding for coding blocks of varying size is rendered more efficient by the usage of a variable length coded syntax element having a prefix and a suffix, wherein the size of the suffix is dependent on the prefix and the size of the current coding block. By this measure, it is feasible to efficiently adapt the length of the variable-length coded syntax element which controls the bi-partitioning of the current coding block to the actual needs, namely the size, of the current coding block, and the variability of the bi-partitioning by varying the wedglet separation line, respectively. The greater the current coding block is, the longer the variable-length coded syntax element may be. This length dependency may even be sufficiently effective in terms of coding efficiency so that the variable length coded syntax element may be coded without context-adaptive entropy coding, but directly or using fixed-equal-probability binary entropy coding.

In one implementation, we propose to use coset decomposition to improve intra prediction mode coding and decoding. In 67 intra-frame prediction modes, 64 prediction modes are selected for coset decomposition, and the remaining three modes are left in a reduced MPM (most probable mode) list. 64 modes are decomposed into cosets, wherein the number of cosets and the number of modes in the cosets are determined by the size of the target block and / or statistics of intra prediction modes of neighboring blocks. And the intra-frame prediction modes in the cosets are arranged according to a likelihood decreasing sequence. The intra prediction mode of the target block is encoded as a coset index and a member index in the coset. The first coset, namely the first mode in the coset, is encoded with bit 0, and the remaining modes are encoded with fixed or variable length codes.

The invention provides a channel state information feedback method and device based on an adaptive feedback rate. The method comprises the following steps: acquiring a channel state information matrix; inputting the sequence into a pre-training marking encoder based on an attention mechanism, and converting the sequence into a symbol sequence with a fixed length; quantizing the symbol sequence into a discrete index sequence through a pre-training vector quantizer and a codebook; determining a target length according to a real-time channel condition or a dynamically allocated system feedback resource based on a preset importance sorting rule obtained by nesting and discarding training, truncating an index sequence arranged according to an importance descending order, and retaining a front-end index to generate a variable-length feedback code word; and sending the variable-length code word to a base station for reconstruction. According to the method, the dynamic self-adaptive optimization of the feedback rate is realized, the spectrum efficiency is effectively improved, the progressive reconstruction is supported by utilizing the inherent importance sorting of the code words, and the robustness of the system is remarkably enhanced.

Encoding and / or decoding a block of a video frame may be based on a previously decoded reference block in the same frame or in a different frame. The reference block may be indicated by a block vector (BV). The BV may be encoded as difference (e.g., block vector difference (BVD)) between a block vector predictor (BVP) and the BV. The BVP may indicate a codeword comprising a prefix part and a suffix part. Efficient entropy coding may be achieved by selectively using variable length coding for the prefix part and the suffix part. For example, variable length coding for the prefix part and the suffix part may be used if the prefix part indicates a maximum prefix value.

The present disclosure relates to a method of encoding and decoding image content and a system of transmitting image content, in particular to a method for decoding image content from an encoded bitstream comprising a plurality of blocks, comprising: dividing a block comprising one or more components of the image content into N single samples and M sample groups corresponding to one of the components, wherein N and M are greater than or equal to 1; decoding each of the N single samples using a sign variable length code to generate one or more decoded single samples; decoding each of the M sample groups using a common prefix entropy code to generate one or more decoded sample groups, each of the M sample groups comprising a variable length prefix and one or more fixed length suffixes representing a plurality of samples; concatenating the decoded single samples and the decoded sample groups into a block of residuals; and reconstructing the image content based on previously reconstructed neighboring blocks and the block of residuals.