28,085 research outputs found
A Universal Parallel Two-Pass MDL Context Tree Compression Algorithm
Computing problems that handle large amounts of data necessitate the use of
lossless data compression for efficient storage and transmission. We present a
novel lossless universal data compression algorithm that uses parallel
computational units to increase the throughput. The length- input sequence
is partitioned into blocks. Processing each block independently of the
other blocks can accelerate the computation by a factor of , but degrades
the compression quality. Instead, our approach is to first estimate the minimum
description length (MDL) context tree source underlying the entire input, and
then encode each of the blocks in parallel based on the MDL source. With
this two-pass approach, the compression loss incurred by using more parallel
units is insignificant. Our algorithm is work-efficient, i.e., its
computational complexity is . Its redundancy is approximately
bits above Rissanen's lower bound on universal compression
performance, with respect to any context tree source whose maximal depth is at
most . We improve the compression by using different quantizers for
states of the context tree based on the number of symbols corresponding to
those states. Numerical results from a prototype implementation suggest that
our algorithm offers a better trade-off between compression and throughput than
competing universal data compression algorithms.Comment: Accepted to Journal of Selected Topics in Signal Processing special
issue on Signal Processing for Big Data (expected publication date June
2015). 10 pages double column, 6 figures, and 2 tables. arXiv admin note:
substantial text overlap with arXiv:1405.6322. Version: Mar 2015: Corrected a
typ
Motion estimation and CABAC VLSI co-processors for real-time high-quality H.264/AVC video coding
Real-time and high-quality video coding is gaining a wide interest in the research and industrial community for different applications. H.264/AVC, a recent standard for high performance video coding, can be successfully exploited in several scenarios including digital video broadcasting, high-definition TV and DVD-based systems, which require to sustain up to tens of Mbits/s. To that purpose this paper proposes optimized architectures for H.264/AVC most critical tasks, Motion estimation and context adaptive binary arithmetic coding. Post synthesis results on sub-micron CMOS standard-cells technologies show that the proposed architectures can actually process in real-time 720 Ă 480 video sequences at 30 frames/s and grant more than 50 Mbits/s. The achieved circuit complexity and power consumption budgets are suitable for their integration in complex VLSI multimedia systems based either on AHB bus centric on-chip communication system or on novel Network-on-Chip (NoC) infrastructures for MPSoC (Multi-Processor System on Chip
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Parallel data compression
Data compression schemes remove data redundancy in communicated and stored data and increase the effective capacities of communication and storage devices. Parallel algorithms and implementations for textual data compression are surveyed. Related concepts from parallel computation and information theory are briefly discussed. Static and dynamic methods for codeword construction and transmission on various models of parallel computation are described. Included are parallel methods which boost system speed by coding data concurrently, and approaches which employ multiple compression techniques to improve compression ratios. Theoretical and empirical comparisons are reported and areas for future research are suggested
A VLSI architecture of JPEG2000 encoder
Copyright @ 2004 IEEEThis paper proposes a VLSI architecture of JPEG2000 encoder, which functionally consists of two parts: discrete wavelet transform (DWT) and embedded block coding with optimized truncation (EBCOT). For DWT, a spatial combinative lifting algorithm (SCLA)-based scheme with both 5/3 reversible and 9/7 irreversible filters is adopted to reduce 50% and 42% multiplication computations, respectively, compared with the conventional lifting-based implementation (LBI). For EBCOT, a dynamic memory control (DMC) strategy of Tier-1 encoding is adopted to reduce 60% scale of the on-chip wavelet coefficient storage and a subband parallel-processing method is employed to speed up the EBCOT context formation (CF) process; an architecture of Tier-2 encoding is presented to reduce the scale of on-chip bitstream buffering from full-tile size down to three-code-block size and considerably eliminate the iterations of the rate-distortion (RD) truncation.This work was supported in part by the China National High Technologies Research Program (863) under Grant 2002AA1Z142
Design of Block Transceivers with Decision Feedback Detection
This paper presents a method for jointly designing the transmitter-receiver
pair in a block-by-block communication system that employs (intra-block)
decision feedback detection. We provide closed-form expressions for
transmitter-receiver pairs that simultaneously minimize the arithmetic mean
squared error (MSE) at the decision point (assuming perfect feedback), the
geometric MSE, and the bit error rate of a uniformly bit-loaded system at
moderate-to-high signal-to-noise ratios. Separate expressions apply for the
``zero-forcing'' and ``minimum MSE'' (MMSE) decision feedback structures. In
the MMSE case, the proposed design also maximizes the Gaussian mutual
information and suggests that one can approach the capacity of the block
transmission system using (independent instances of) the same (Gaussian) code
for each element of the block. Our simulation studies indicate that the
proposed transceivers perform significantly better than standard transceivers,
and that they retain their performance advantages in the presence of error
propagation.Comment: 14 pages, 8 figures, to appear in the IEEE Transactions on Signal
Processin
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