For coding of quantized transform coefficients, a coded block pattern (CBP) is a key syntax element to represent the existence of coefficients in a macroblock efficiently. In H.264/AVC, the CBP is coded by using a fix...
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For coding of quantized transform coefficients, a coded block pattern (CBP) is a key syntax element to represent the existence of coefficients in a macroblock efficiently. In H.264/AVC, the CBP is coded by using a fixed variable length coding table, called Exp-Golomb codes. However, since the CBP is highly affected by the change of quantization parameter (QP), in this paper, we show the CBP distributions according to the change of QP and propose an context-adaptive CBP coding method. The proposed scheme selects the coding table adaptively based on the context of neighbors' CBP. Experimental results show that the proposed scheme reduces average 1.15% in total bit rate and 12.54% in CBP bit rate compared to the anchor, H.264/AVC.
In a wireless video communication system, the video encoder needs to dynamically control the coding parameters based on the instantaneous video statistics and channel condition to achieve the best video quality. An ac...
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ISBN:
(纸本)9780769543529
In a wireless video communication system, the video encoder needs to dynamically control the coding parameters based on the instantaneous video statistics and channel condition to achieve the best video quality. An accurate bit rate model can help the encoder to achieve accurate bit rate control and good rate-distortion (R-D) performance. In this paper, we improve the bit rate model by modeling the component of run-level mapping plus entropy coding as the process of choosing different codebooks for different quantized transform coefficients. We also compensate the mismatch between the true histogram and the assumed Laplacian distribution in a parametric model by utilizing the deviation of the estimation in previous frames.
The paper presents design and implementation of a wireless sensor node suitable for medical applications. As physiological signals are highly redundant, the data compression algorithms (Huffman's coding) are used ...
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ISBN:
(纸本)9781424497560
The paper presents design and implementation of a wireless sensor node suitable for medical applications. As physiological signals are highly redundant, the data compression algorithms (Huffman's coding) are used to save energy and improve the node performance. Design is based on the ARM Cortex M1 processor and implemented in FPGA.
Context-based Adaptive Variable Length coding (CAVLC) as a new entropy coding algorithm has been introduced into H.264/AVC standard. Through analysing the CAVLC coding algorithm detailedly, the paper proposes an overl...
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ISBN:
(纸本)9783037850978
Context-based Adaptive Variable Length coding (CAVLC) as a new entropy coding algorithm has been introduced into H.264/AVC standard. Through analysing the CAVLC coding algorithm detailedly, the paper proposes an overlapping coverage storage method and a new stream merger method, and gives the specific implementation. This idea improves the structure and performance of the complex module and reduces the implementation complexity. The experimental results show that the proposed entropy encoder is correct, and the highest coding frequency of 81.70MHz can be achieved. Meanwhile all the hardware resource consumption is less than 2% of total hardware resources. The new entropy encoder achieves a better balance in system performance and resource consumption.
This paper presents a high-throughput hardware architecture for H. 264/ AVC CAVLC encoding. Our scheme eliminates the pipeline stage of computing the coefficient statistics (as adopted by state-ofthe- art hardware arc...
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ISBN:
(纸本)9781457713033
This paper presents a high-throughput hardware architecture for H. 264/ AVC CAVLC encoding. Our scheme eliminates the pipeline stage of computing the coefficient statistics (as adopted by state-ofthe- art hardware architectures) with a pre-processing stage during the quantization in order to avoid the extra looping logic in CAVLC. This provides significant performance improvement compared to state-of-the-art (saving of 16 cycles per 4x4 sub-block compared to [2]). Furthermore, our hardware architecture employs parallel processing of Trailing Ones (which is one of the inherently sequential steps in CAVLC) and encodes levels and runs in parallel in the same pipeline stage. An intelligent bitstream writing logic generates the compliant bitstream. Compared to state-of-the-art, our proposed hardware architecture requires 72% reduced area and achieves 2x higher throughput, while processing HD1080p@ 30fps.
In this paper, we outline a coding strategy that initializes the entropy coding engine of a video codec at pre-defined locations within a bit-stream. Coupled with the causal dependencies of state-of-the-art video codi...
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ISBN:
(纸本)9781457713033
In this paper, we outline a coding strategy that initializes the entropy coding engine of a video codec at pre-defined locations within a bit-stream. Coupled with the causal dependencies of state-of-the-art video coding systems, this enables wavefront processing of the entropy decoding and reconstruction process simultaneously. Approaches to wavefront processing have been considered by others, and those methods either address the reconstruction process solely or require transmitting image data in non-raster scan order. Here, our key contribution is that we enable simultaneous entropy/reconstruction wavefront processing while still preserving a raster scan strategy. In this paper, we describe the system, as well as different strategies for initializing the context models. The performance of the proposed methods is evaluated, and the bitrate increase is shown to be nominal.
Reduced reference video quality assessment techniques provide a practical and convenient way of evaluating the quality of a processed video. In this paper, we propose a method to efficiently compress standardized VQM ...
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A context adaptive variable length coding (CAVLC) decoder do not know the exact start position of the k-th syntax element in a bitstream until it finishes parsing the (k-1)-th syntax element. It makes a parallel CAVLC...
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ISBN:
(纸本)9780819484086
A context adaptive variable length coding (CAVLC) decoder do not know the exact start position of the k-th syntax element in a bitstream until it finishes parsing the (k-1)-th syntax element. It makes a parallel CAVLC decoding difficult. It significantly increases implementation cost to predict the exact start position of a syntax element prior to parsing its previous one. In this paper, we propose a new bitstream structure to concurrently access multiple syntax elements for parallel CAVLC decoding. The method divides a bit-stream into N kinds of segments whose size is M bits and puts syntax elements into the segments, based on a proposed rule. Then, a CAVLC decoder can simultaneously access N segments to read N syntax elements from a single bitstream and decode them in parallel. This technique increases the speed of CAVLC decoding by up to N times. Since the method just rearranges the generated bitstream, it does not affect coding efficiency. Experimental results show that the proposed algorithm significantly increases decoding speed.
This paper discusses pattern matching on Variable-to-Fixed-length codes (VF codes). A VF code is a coding scheme whose codeword lengths are fixed, and thus it is suitable for comprssed pattern matching. However, there...
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ISBN:
(纸本)9780769543529
This paper discusses pattern matching on Variable-to-Fixed-length codes (VF codes). A VF code is a coding scheme whose codeword lengths are fixed, and thus it is suitable for comprssed pattern matching. However, there are few reports showing its efficiency so far. We present some experimental results about the compression ratios and encoding/decoding speeds besides pattern matching performance on Tunstall codes and STVF codes. We also present how an entropy coding affects to VF codes.
In 1993 Boncelet introduced a block arithmetic scheme for entropy coding that combines advantages of stream arithmetic coding with algorithmic simplicity. It is a variable-to-fixed length encoding in which the source ...
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ISBN:
(纸本)9781457705953
In 1993 Boncelet introduced a block arithmetic scheme for entropy coding that combines advantages of stream arithmetic coding with algorithmic simplicity. It is a variable-to-fixed length encoding in which the source sequence is partitioned into variable length phrases that are encoded by a fixed length dictionary pointer. The parsing is accomplished through a complete parsing tree whose leaves represent phrases. This tree, in its suboptimal heuristic version, is constructed by a simple divide and conquer algorithm, whose analysis is the subject of this paper. For a memoryless source, we first derive the average redundancy and compare it to the (asymptotically) optimal Tunstall's algorithm. Then we prove a central limit theorem for the phrase length. To establish these results, we apply powerful techniques such as Dirichlet series, Mellin-Perron formula, and (extended) Tauberian theorems of Wiener-Ikehara.
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