Enhanced aacPlus is an audio codec which is composed of advanced audio coding (AAC), spectral band replication (SBR), and parametric stereo (PS) for efficient audio coding at low bit rates. We propose a new coding sch...
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Enhanced aacPlus is an audio codec which is composed of advanced audio coding (AAC), spectral band replication (SBR), and parametric stereo (PS) for efficient audio coding at low bit rates. We propose a new coding scheme for lossless bit rate reduction of PS in enhanced aacPlus. We first determine the optimal contexts for context-based coding of quantized stereo parameter indexes in PS. Then we propose a coding scheme which is based on context-based coding using the determined optimal contexts in conjunction with arithmetic coding. The proposed scheme has normal and memory-reduced versions, both of which are shown to guarantee significant and consistent lossless bit rate reduction of PS. The saved bits by the proposed scheme can be used for the other modules of enhanced aacPlus, AAC and SBR.
In this paper, a novel wavelet-based composite mesh coding scheme is presented. In contrast to the state-of-the-art scalable interband mesh codec, the proposed codec relies on composite dependency models that capture ...
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ISBN:
(纸本)9781424456536
In this paper, a novel wavelet-based composite mesh coding scheme is presented. In contrast to the state-of-the-art scalable interband mesh codec, the proposed codec relies on composite dependency models that capture both the interband and intraband statistical dependencies between wavelet coefficients. Additionally, each wavelet subband is processed independently, which allows for parallelized processing and for a progressive reconstruction of each mesh resolution level. Compared to the state-of-the-art, the proposed codec yields for almost all rate points superior compression performance in L-2 -sense. Furthermore, the generated bitstreams are near-optimal in rate-distortion sense, which eliminates the need of a post-compression rate-distortion optimization technique.
Nowadays, with the increase resolution of Dynamic Vision Sensor (DVS), efficient compression algorithm for event stream is needed urgently. Conventional DVS system encodes event data in address event representation (A...
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ISBN:
(纸本)9798350330991;9798350331004
Nowadays, with the increase resolution of Dynamic Vision Sensor (DVS), efficient compression algorithm for event stream is needed urgently. Conventional DVS system encodes event data in address event representation (AER) for output while ignores the data redundancy imposed by the correlation of events. To address this challenge, this paper first analyzes the spatiotemporal characteristics of event stream and the impact of readout circuits. based on the analysis, the context-based encoding strategies for spatial address, timestamp and polarity of events are proposed respectively with the consideration of data flow in DVS hardware. Besides, the hardware architecture with high parallelism is presented to implement the compression algorithm, which achieves high throughput at an affordable cost. The hardware is implemented in the 55nm process as part of a 512x512 resolution DVS. The experimental results demonstrate that our methods achieves higher average compression ratio compared to conventional and DVS-specific coding algorithms.
Modern image and video compression technologies include both lossless compression methods, such as entropy coding, Inter-frame and Intra-frame coding, and lossy compression methods, such as discrete orthogonal transfo...
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ISBN:
(纸本)9783030366254;9783030366247
Modern image and video compression technologies include both lossless compression methods, such as entropy coding, Inter-frame and Intra-frame coding, and lossy compression methods, such as discrete orthogonal transforms with quantization. All these techniques are actively applied in video codecs based on the H.264 and H.265 standards. Discrete wavelet transform (DWT) is one of the most perspective versions of discrete orthogonal transforms. Both Intra-frame coding and wavelet decomposition of images allow to reduce the volume of transmitted data, but they are not used together in video coding systems. The combined usage of these methods seems to be a promising approach in terms of visual data compression. Thereby the aim of this research is to develop a new technique based on the combination of Intra-frame coding and the DWT and to test the applicability of the proposed method in the image compression tasks. The effectiveness of various implementations of the proposed algorithm, including those based on contexts and using several levels of wavelet decomposition of images, was evaluated in the study.
In this paper, we propose an embedded satellite image compression method using Weighted ZeroBlock coding (WZBC) and optimal sorting. In order to reduce average codeword length, Set Partition Embedded block (SPECK) and...
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In this paper, we propose an embedded satellite image compression method using Weighted ZeroBlock coding (WZBC) and optimal sorting. In order to reduce average codeword length, Set Partition Embedded block (SPECK) and Embedded ZeroBlock Coder (EZBC) both encode significant block-sets with fixed-length bits, while WZBC assigns different-length bits to encode block-sets which contain different numbers of significant sub-blocks. In view of the context correlation among coefficients/blocks, WZBC employs a weight context to optimize the scanning order of the significance testing and the rate-distortion performance. Experimental results show that the proposed WZBC in binary coding mode provides excellent coding performance compared with those of SPECK and Set Partitioning In Hierarchical Trees (SPIHT) which use arithmetic coding, and can even closely approach that of JPEG2000. When arithmetic coding is extensively used, the proposed method has clear advantages.
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