Real-time video communication is critically hampered by packet loss. Building on the neural video codec (NVC) and exploiting the statistics of its latent representations, we propose a channel importance-aware redundancy framework that eliminates insignificant channels and reallocates high redundancy to protect important channels for loss-resilient video coding. We first develop a channel-wise importance evaluation method based on the in-distribution (IND) region length criterion [1] for latent representations of prediction residuals and motion vectors produced by NVCs. Consequently, we derive a heuristic that adapts the number of protected channels to the packet loss rate (PLR). More channels are retained at low PLRs to improve video quality, while only a few critical channels are kept and assigned higher redundancy for enhanced robustness at high PLRs. Experimental results show that the proposed method provides more graceful quality degradation and maintains significant performance advantages, particularly under high PLRs, as illustrated in Figure 1.

Despite strong generalization ability, large language models (LLMs) are resource-intensive to deploy. Post-training quantization (PTQ) effectively compresses pretrained LLMs without retraining. Although recent studies target extremely low-bit quantization, most methods rely on extra parameters and the effective bit-width usually exceeds 2 bits. We introduce a saliency-guided mixed-precision PTQ framework that achieves an average bit-width of 1.70 bits while maintaining competitive performance. The proposed method allocates bit-widths across weight groups under a strict total budget, guided by a cross-precision saliency metric. The key innovation is a learnable affine transformation consisting of rotation, scaling, and shifting to align quantization grids with local weight distributions to minimize error. Experiments show that the proposed method matches state-of-the-art low-bit PTQ performance, while reducing the average bit-width by approximately 0.55 bits in Table 1.

Learned image compression (LIC) has recently emerged as a promising alternative to realize transform-based coding. Contrary to widely studied transform and entropy modeling in LIC, most LIC methods are limited to uniform scalar quantization and existing vector quantization (VQ) methods are restricted by the soft-to-hard quantization strategy. In this paper, we propose a novel entropy relaxed lattice vector quantization (ERLVQ) scheme for LIC. ERLVQ achieves a tractable dimension-wise approximation to the probability mass function for the complex Voronoi regions in a general class of lattices. Instead of directly performing probabilistic estimation on the lattices, ERLVQ equivalently aligns complex Voronoi regions with a set of complete and non-overlapping hypercubes in a projected parametric domain. Space covering technique is then developed to generating hypercubes with their centers fixed to integer projected lattice points and their volumes equaling the Voronoi regions to enable separable dimension-wise estimation of multi-variate probability mass functions. The proposed ERLVQ is the first to adapt to arbitrary lattices for VQ based on LIC and can be embedded into existing LIC methods. Experimental results demonstrate that the proposed ERLVQ is superior to the uniform scalar quantization (USQ) and existing lattice VQ methods [1] on prevailing LIC baselines, as shown in Table 1 .

Network quantization is promising to alleviate the storage and deployment burden for deep neural networks. However, existing methods focus on directly quantizing the network parameters but ignore the correlations between the initialized parameters (generated by random seeds) and the optimized parameters (obtained when the network training converges). In this paper, we reveal the redundancy between the initialized and optimized parameters and propose a novel quantization scheme for network parameters with rescaled initialization. We develop a novel quantization scheme for quantizing the delta parameters, i.e. , the difference between the optimized parameters and the rescaled initialization, as shown in Figure 1 . The scale is learned to adapt the weight regularization in training by minimizing the rounding error and penalizing the long-tailed distribution of the delta parameter. Adaptive rounding is further presented to calibrate the rounding direction of the delta parameter via a learnable bias. The proposed method can achieve high-efficiency prediction of network parameters and consistent performance gains with a trivial overhead of single random seed. Extensive experimental results demonstrate its superior performance on various popular network architectures, as exemplified in Table 1 .

End-to-end learned image compression (LIC) has become promising alternatives for lossy image compression. However, deployments of LIC models are limited in real-world applications due to excessive network parameters and high computational complexity. Existing LIC models realized with integer networks are significantly de-graded in rate-distortion (R-D) performance. In this paper, we propose a novel fully integerized LIC model that simultaneously achieves channel-wise weight and 8-bit activation quantization for alleviating the loss of R-D performance. For weight quantization, we develop an internal bit width increment (IBWI) via nonlinear logarithmic mapping to convert the stored low-precision integer weights to high bit-width weights for inference. Moreover, outlier channel splitting (OCS) [1] is employed to address large outliers of weight distribution by duplicating channels and constrain the integer weights within the scope of INT8. For activation quantization, we leverage activation equalization to balance the channel-wise distribution of activations. Experimental results demonstrate that the proposed method achieves a reduction of 75% storage cost with subtle performance loss compared to full-precision pre-trained models, and outperforms existing integer-only networks, as shown in Table 1.

Quantizing one single deep neural network into multiple compression rates (precisions) has been recently considered for flexible deployments in real-world scenarios. In this paper, we propose a novel scheme that achieves progressive bit-width allocation and joint training to simultaneously optimize mixed-precision quantized networks under multiple compression rates. Specifically, we develop a progressive bit-width allocation with switchable quantization step size to enable mixed-precision quantization based on analytic sensitivity of network layers under multiple compression rates. Furthermore, we achieve joint training for quantized networks under different compression rates via knowledge distillation to exploit their correlations based on the shared network structure. Experimental results show that the proposed scheme outperforms AdaBits [1] in various networks on CIFAR-10 and ImageNet.

Existing entropy models in learned image compression are cumbersome to generate fixed mean and variance for estimating Gaussian distributions for latent representation. In this paper, we propose a novel entropy model based on Gaussian process regression (GPR) that flexibly predicts the mean of Gaussians with posterior distributions characterized by covari-ance functions spanned in the high-dimensional feature space. Furthermore, we develop the rate-distortion optimization based on the proposed entropy model by approximating the bitrates with the evidence lower bound (ELBO) derived via variational inference for GPR. The proposed model can be seamlessly integrated into existing end-to-end optimized frame-works by substituting the masked convolution based autoregressive models. Experimental results demonstrate that the proposed model outperforms conventional image compression methods such as JPEG2000 and BPG, as well as recent learning based methods on the Kodak dataset in terms of rate-distortion performance.

Existing methods for cross-component prediction focus on the chroma intra pre-diction but neglect the chroma prediction across multiple frames. In this paper, we propose a novel compression framework that leverages chroma frame sampling and inter-frame chroma prediction to address this problem. Specifically, chroma frame sampling discards the chroma components in inter-predicted frames to further reduce the bit consumption, whereas inter-frame chroma prediction recovers the discarded chroma components with optical flow estimation and post-training optimization for a guaranteed fidelity. To our best knowledge, this paper is the first attempt to achieve deep learning-based inter prediction of chroma components. To accommodate the proposed framework, we redesign the HEVC codec to enable hybrid coding of luma and chroma components. Experimental results show that the proposed framework achieves up to 0.76% BD-rate reduction when compared to standard HEVC.

3-D point clouds rendering solid representations of scenes or objects often carry a tremendous amount of points, compulsorily requesting high-efficiency compression for storage and transmission. In this paper, we propose a novel$p$-Laplacian embedding graph dictionary learning algorithm for 3-D point cloud attribute compression. The proposed method integrates the underlying graph topology to the learned graph dictionary capitalizing on$p$-Laplacian eigenfunctions and leads to parsimonious representations of 3-D point clouds. We further devise alternating optimization with the help of ADMM to efficiently solve the resulting non-convex minimization problem.

We propose a structured pruning method to achieve a light-weighted decoder of learned image compression to accommodate various terminals. The structured pruning method identifies the effectiveness of each channel of decoder via gradient ascent and gradient descent while maintaining the encoder and entropy model. To our best knowledge, this paper is the first attempt to design a structured pruning method for universal pretrained learned image compression. Experimental results demonstrate that the proposed method can reduce about 40% parameters and save 25% inference time at the cost of 0.23 dB BD-PSNR and 4.33% BD-rate change.

The Cox proportional hazards model is a popular semi-parametric model for survival analysis. In this paper, we aim at developing a federated algorithm for the Cox proportional hazards model over vertically partitioned data (i.e., data from the same patient are stored at different institutions). We propose a novel algorithm, namely VERTICOX, to obtain the global model parameters in a distributed fashion based on the Alternating Direction Method of Multipliers (ADMM) framework. The proposed model computes intermediary statistics and exchanges them to calculate the global model without collecting individual patient-level data. We demonstrate that our algorithm achieves equivalent accuracy for the estimation of model parameters and statistics to that of its centralized realization. The proposed algorithm converges linearly under the ADMM framework. Its computational complexity and communication costs are polynomially and linearly associated with the number of subjects, respectively. Experimental results show that VERTICOX can achieve accurate model parameter estimation to support federated survival analysis over vertically distributed data by saving bandwidth and avoiding exchange of information about individual patients. The source code for VERTICOX is available at: https://github.com/daiwenrui/VERTICOX.

Cloud service has been emerging as a promising alternative to handle massive volumes of video sequences triggered by increasing demands on video service, especially surveillance and entertainment. Lossless compression of encoded video bitstreams can further eliminate the redundancies without altering the contents and facilitate the efficiency of cloud storage. In this paper, we propose a novel lossless compression scheme to further compress the video bitstreams generated by the state-of-the-art hybrid coding frameworks like H.264/AVC and HEVC. Different from transcoding, the proposed scheme develops frequency prediction and Macro Block (MB) merging to eliminate the redundancies remained in the intra-and inter-predicted frames with a strict guarantee of video fidelity. To our best knowledge, this paper is the first attempt to realize lossless compression of video bitstreams generated by advanced coding standards H.264/AVC and HEVC. Experimental results demonstrate that the proposed scheme can achieve compression gains of 17.38% and 10.85% on standard test sequences and surveillance videos, respectively.

Deep learning has been widely adopted in compression sensing (CS) to achieve superior reconstruction quality, but is restricted by the black-box architecture in network design and lack of interpretability. In this paper, we propose a novel deep network-based CS framework via unfolding the$\ell_{0}$-constrained convolutional sparse coding (CSC). The proposed method incorporates deep neural networks (DNNs) into the state-of-the-art optimization paradigm of alternating direction method of multipliers (ADMM). CS reconstruction can be improved with the compact and shift-invariant sparse representation under the merits of CSC and DNNs with learnable parameters. Convergence analysis demonstrates that the proposed method is guaranteed to converge, when the network parameters are reused for all the building blocks. Experimental results demonstrate that the proposed method is competitive or outperform the state-of-the-art DNN-based methods in CS of natural images and magnetic resonance imaging (MRI).

Generative model has emerged as a disruptive alternative for lossy compression of natural images, but suffers from the low-fidelity reconstruction. In this paper, we propose a noise-to-compression variational antoencoder (NC-VAE) to achieve efficient rate-distortion optimization (RDO) for end-to-end optimized image compression with a guarantee of fidelity. The proposed NC-VAE improves rate-distortion performance by adaptively adjusting the distribution of latent variables with trainable noise perturbation. Consequently, high-efficiency RDO is developed based on the distribution of latent variables for simplified decoder. Furthermore, robust end-to-end learning is developed over the corrupted inputs to suppress the deformation and color drift in standard VAE based generative models. Experimental results show that NC-VAE outperforms the state-of-the-art lossy image coders and recent end-to-end optimized compression methods in low bit-rate region, i.e., below 0.2 bits per pixel (bpp).

Filter bank based convolutional networks (FBCNs) enable efficient separable multiscale and multidirectional decomposition with a convolutional cascade of 1-D radial and directional filter banks. In this paper, we propose a two-stage subband coding framework for FBCN analysis coefficients using a SPIHT-like algorithm and subsequent primitive-based adaptive arithmetic coding (AAC). The SPIHT-like algorithm extends spatial orientation tree to exploit inter-subband dependency between subbands of different scales and directions. Mutual information is estimated for information-theoretical measurement to formulate such dependencies. Various primitives are designed adaptively encode the generated bitstream by fitting its varying lists and passes. Neural networks are leveraged to improve probability estimation for AAC, where nonlinear prediction is made based on contexts regarding scales, directions, locations and significance of analysis coefficients. Experimental results show that the proposed framework improves the lossy coding performance for FBCN analysis coefficients in comparison to the state-of-the-arts subband coding schemes SPIHT.

Demanding for efficient compression and storage of DNA sequences has been rising with the rapid growth of DNA sequencing technologies. Existing reference-based algorithms map all patterns to regions found in the reference sequence, which lead to redundancy of incomplete similarity. This paper proposes an efficient reference-based method for DNA sequence compression that integrates FM-index and complementary context models to improve compression performance. The proposed method introduces FM-index to represent the full-text matching for exact repeats between the target and reference sequences. For unmatched symbols, complementary context models are leveraged to make weighted estimation conditioned on variable-order contexts. Reversed reference index is used to guarantee the longest match of variable-length substrings. Experimental results show that the proposed method can achieve a 213-fold compression ratio when tested on the first Korean personal genome sequence data set.

Tensor-based compressive sensing (CS) can preserve the intrinsic multidimensional structures with a reduced computational complexity. However, its recovery performance is degraded by simple sparsity. This paper proposes an efficient recovery algorithm GT-ADMM to solve a nonconvex optimization problem for tensor-based CS with group sparsity. Group-sparse representations of tensors is derived based on the Kronecker product of adaptively trained basis. The proposed algorithm incorporates alternating direction method of multipliers (ADMM) to obtain desirable recovery quality with improved efficiency. It requires few degrees of freedom to achieve tensor recovery with a guarantee of minimized approximation error. Experimental results demonstrate that the proposed algorithm outperforms state-of-the-art tensor-based methods in compressive video sampling.

Conventional Compressive Sensing (CS) obscures the intrinsic structures of multidimensional signals with the vectorized representation. Although tensor-based CS methods can preserve the intrinsic multidimensional structures with reduced computational complexity, their sampling efficiency and recovery performance are degraded with the assumption of standard/simple sparsity. This paper proposes a general and adaptive model that incorporates structured sparsity into tensor representation to fit the varying nonstationary statistics of multidimensional signals. To guarantee the block sparsity, subspace clustering is adopted to adaptively generate the union of tensor subspaces with its basis of each tensor subspace learned for optimized representation. For sampled tensors, the stable recovery algorithm is developed to achieve desirable recovery performance using fewer degrees of freedom. Moreover, the proposed model inherits the merit from tensor-based CS to alleviate the computational and storage burden in sampling and recovery. Experimental results demonstrate that the proposed model can achieve better recovery performance in video sampling in comparison to the state-of-the-art tensor-based method.

Summary form only given. This paper proposes a bi-directional context modeling (BCM) technique for reference-free genome sequence compression, which constructs its contexts by combining arbitrary predicted symbols in two directions corresponding to approximate repeats and non-repeat regions. Thus, BCM can sequentially predict DNA sequences with weighted conditional probabilities that simultaneously exploit the correlations among matched approximate repeats and fit the variable-order statistics in non-repeat regions. Moreover, BCM eliminates the overhead of pointer information for specifying approximate repeats, as it is synchronized in both encoder and decoder. In theory, we show that upper bounds of excess model redundancy led by BCM vanish with the growth of sequence size. Experimental results show that BCM outperforms the state-of-the-art reference-free compressors like FCM and CTW+LZ.

Existing sparse representation with subspace learning is hampered by the intersection of subspaces of bases. With structured sparsity to enable the prior knowledge of signal statistics, this paper proposes a novel compressive video sampling by subspace learning to minimize the intersection of subspaces. As the measurement, the block coherence is optimized with the regularized learning to generate a class of independent bases associated with the subspaces. Thus, the proposed framework can make a compact block sparse representation based on the derived basis in an efficient and adaptive manner. The block-based recovery of video sequences is demonstrated to be stable under the constraint of block restricted isometric property (RIP). Experimental results show that the proposed method outperforms existing compressive video sampling schemes.

This paper proposes an adaptive dictionary learning approach based on sub modular optimization. A candidate atom set is constructed based on multiple bases from the combination of analytic and trained dictionaries. With the low-frequency components by the analytic DCT atoms, high-resolution dictionaries can be inferred through online learning to make efficient approximation with rapid convergence. It is formulated as a combinatorial optimization for approximate sub modularity, which is suitable for sparse representation based on dictionaries with arbitrary structures. In single-image super-resolution, the proposed scheme has been demonstrated to improve the reconstruction performance in comparison with double sparsity dictionary in terms of both objective and subjective restoration quality.

To enable learning-based video coding for transmission over heterogenous networks, this paper proposes a scalable video coding framework by progressive dictionary learning. With the hierarchical B-picture prediction structure, the inter-predicted frames would be reconstructed in terms of the spatio-temporal dictionary in a successive sense. Within the progressive dictionary learning, the training set is enriched with the samples from the reconstructed frames in the coarse layer. Through minimizing the expected cost, the stochastic gradient descent is leveraged to update the dictionary for practical coding. It is demonstrated that the learning-based scalable framework can effectively guarantee the consistency of motion trajectory with the well-designed spatio-temporal dictionary.

LS-based adaptation cannot fully exploit high-dimensional correlations in image signals, as linear prediction model in the input space of supports is undesirable to capture higher order statistics. This paper proposes Gaussian process regression for prediction in lossless image coding. Incorporating kernel functions, the prediction support is projected into a high-dimensional feature space to fit the anisotropic and nonlinear image statistics. Instead of directly conditioned on the support, Gaussian process regression is leveraged to make prediction in the feature space. The model parameters are optimized by measuring the similarities based on the training set, which is evaluated by combined kernel function in the sense of translation and rotation invariance among supports mapped in the feature space. Experimental results show that the proposed predictor outperforms most benchmark predictors reported.

Previous reference-based compression on DNA sequences do not fully exploit the intrinsic statistics by merely concerning the approximate matches. In this paper, an adaptive difference distribution-based coding framework is proposed by the fragments of nucleotides with a hierarchical tree structure. To keep the distribution of difference sequence from the reference and target sequences concentrated, the sub-fragment size and matching offset for predicting are flexible to the stepped size structure. The matching with approximate repeats in reference will be imposed with the Hamming-like weighted distance measure function in a local region closed to the current fragment, such that the accuracy of matching and the overhead of describing matching offset can be balanced. A well-designed coding scheme will make compact both the difference sequence and the additional parameters, e.g. sub-fragment size and matching offset. Experimental results show that the proposed scheme achieves 150% compression improvement in comparison with the best reference-based compressor GReEn.

In this paper, we develop a novel genome compression framework based on distributed source coding (DSC)[3], which is specially tailored to the need of miniaturized devices. At the encoder side, subsequences with adaptive code length can be compressed flexibly through either low complexity DSC based syndrome coding or hash coding with the decision determined by the existence of variations between source and reference known from the decoder feedback. Moreover, to tackle the variations between source and reference at the decoder, we carefully designed a factor graph based low-density parity-check (LDPC) decoder, which automatically detects insertion, deletion and substitution.

In this paper, we propose the bitwise structured prediction model for lossless image coding, especially for the oscillatory regions. The learning-based model utilizes the regular features obtained from the predicted local data. At first, the pixel-wise prediction is decomposed into the bitwise ones. In each bit plane, the prediction of the current bit is simplified to the max margin estimation for the 0/1 prediction problem and obtained directly conditioned on the neighboring predicted bits. Furthermore, since the decreasing dependencies of neighboring bits in lower bit plane lead to the turbulence of predictive results, the structured prediction is proposed to establish the Markov network to constrain the outputs of the bit planes, and suppress the prediction errors with a well-defined loss function. Consequently, the min-max formulation is proposed for the concurrent optimization for maximizing the 0/1 margin of all the bit planes.

The sequential context modeling framework is generalized to a non-sequential one by context relaxation from consecutive suffix of the subsequences of symbols to the permutation of the preceding symbols as result of considering complex context structures in such sources as video and program binaries. Context weighting tree is also extended to a series of context trees which are built according to the "model tree", in which the descendent relationship in the formation of non-sequential context sets is described. Model redundancy and maximum a posteriori model in the framework are discussed and compared. A decision method based on the greedy algorithm is proposed to customize sets of models fitting the concrete sources. Brief description of application to executable data files incorporating with the semantics and syntax constraints are given and experiment are made accordingly as a validation.