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Search Results: 1 - 10 of 4050 matches for " video coding "
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Distributed Video Coding Using LDPC Codes for Wireless Video  [PDF]
P. APARNA, Sivaprakash REDDY, Sumam DAVID
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.14041
Abstract: Popular video coding standards like H.264 and MPEG working on the principle of motion-compensated pre-dictive coding demand much of the computational resources at the encoder increasing its complexity. Such bulky encoders are not suitable for applications like wireless low power surveillance, multimedia sensor networks, wireless PC cameras, mobile camera phones etc. New video coding scheme based on the principle of distributed source coding is looked upon in this paper. This scheme supports a low complexity encoder, at the same time trying to achieve the rate distortion performance of conventional video codecs. Current im-plementation uses LDPC codes for syndrome coding.
A Novel Efficient Mode Selection Approach for H.264  [PDF]
Lu Lu, Wei Zhou
Journal of Software Engineering and Applications (JSEA) , 2010, DOI: 10.4236/jsea.2010.35053
Abstract: H.264 video coding standard introduces motion estimation with multiple block sizes to achieve a considerably higher coding efficiency than other video coding algorithms. However, this comes at the greatly increased computing complexity at the encoder. In this paper, a method is proposed to eliminate some redundant coding modes that contribute very little coding gain. The simulation results show that the algorithm can remarkably decrease the complexity at the encoder while keeping satisfying coding efficiency.
Improving the Erroe Resilience of region of interest Based Video Coding Schemes
P Subramanian,Dr N R Alamelu,Dr M Aramudhan
International Journal of Computer Technology and Applications , 2011,
Abstract: Transmission of compressed video is prone to errors due to the spatiotemporal prediction coding structure and variable length coding at the source encoder. A single incorrect recovered pixel in a reference frame can lead to more errors in the following reconstructed frames. The video has to be coded in a resilient format to combat the channel errors. There has been a lot of research to make the video coding and transmission resilient to transmission errors and various error resilient techniques have been developed for video coding. In many applications, there exist one or more regions in a video frame that have higher importance than the rest of the frame. For such applications, Region of Interest coding aims at providing better fidelity and better protection against errors in the ROI as opposed to the rest of the frame. This paper reviews the existing error resilient schemes available for making the region of interest based video coding more error resilient.
Compression of ECG signal using video codec technology-like scheme  [PDF]
Dihu Chen, Sheng Yang
Journal of Biomedical Science and Engineering (JBiSE) , 2008, DOI: 10.4236/jbise.2008.11004
Abstract: In this paper, we present a method using video codec technology to compress ECG signals. This method exploits both intra-beat and inter-beat correlations of the ECG signals to achieve high compression ratios (CR) and a low percent root mean square difference (PRD). Since ECG signals have both intra-beat and inter-beat redundancies like video signals, which have both intra-frame and inter-frame correlation, video codec technology can be used for ECG compression. In order to do this, some pre-process will be needed. The ECG signals should firstly be segmented and normalized to a sequence of beat cycles with the same length, and then these beat cycles can be treated as picture frames and compressed with video codec technology. We have used records from MIT-BIH arrhythmia database to evaluate our algorithm. Results show that, besides compression efficiently, this algorithm has the advantages of resolution adjustable, random access and flexibility for irregular period and QRS false detection.
The Performance of MANET Routing Protocols for Scalable Video Communication  [PDF]
Mohammed Halloush, Hussein R. Al-Zoubi, Zakaria Al-Qudah, Osameh Alkofahi
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.52012
Abstract:

Mobile Ad-hoc Networks (MANETs) operate without infrastructure where nodes can move randomly. Therefore, routing in MANETs is a challenging task. In this paper we evaluate the performance of three important MANET routing protocols: Ad hoc On-Demand Distance Vector (AODV), Dynamic Source Routing (DSR) and Optimized Link State Routing (OLSR) when employed to forward scalable video contents. AODV and DSR are reactive protocols in that routing paths are established once needed. On the other hand, OLSR is a proactive routing protocol where routing information is exchanged and maintained continuously. The goal of the performance evaluation in this study is to assess the performance of AODV, DSR and OLSR in communicating scalable video contents. In the simulation part of this paper, a real video sequence is communicated where the characteristics and quality of the video decoded at receiver nodes are evaluated. NS2 along with extensions and other evaluation frameworks have been used to assess the performance of the MANET routing protocols when used for scalable video communication. The framework allows starting from a raw video that is encoded, packetized, transmitted through a network topology and collected at receiver to be decoded, played, and evaluated. Delay and timing constraints are taken into consideration when decoding the received video packets.


Very Low Bit-Rate Video Coding by Combining H.264/AVC Standard and 2-D Discrete Wavelet Transform  [PDF]
Ali Aghagolzadeh, Saeed Meshgini, Mehdi Nooshyar, Mehdi Aghagolzadeh
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.24044
Abstract: In this paper, we propose a new method for very low bit-rate video coding that combines H.264/AVC standard and two-dimensional discrete wavelet transform. In this method, first a two dimensional wavelet transform is applied on each video frame independently to extract the low frequency components for each frame and then the low frequency parts of all frames are coded using H.264/AVC codec. On the other hand, the high frequency parts of the video frames are coded by Run Length Coding algorithm, after applying a threshold to neglect the low value coefficients. Experiments show that our proposed method can achieve better rate-distortion performance at very low bit-rate applications below 16 kbits/s compared to applying H.264/AVC standard directly to all frames. Applications of our proposed video coding technique include video telephony, video-conferencing, transmitting or receiving video over half-rate traffic channels of GSM networks.
Research on Efficiency Improvement of Scalable Video Source Coding in Frequency Domain
本刊采用“图象”等专业用词的说明——答读者问

Guo Danpeng,Qiu Junhai,Zhang Chuntian,Liu Feng,
Guo Danpeng
,Qiu Junhai,Zhang Chuntian,Liu Feng

中国图象图形学报 , 1997,
Abstract: 本刊采用“图象”等专业用词的说明——答读者问在历史和传统文化习惯上,通常描述自然性景物和科学技术领域的研究对象或实验结果时,用到“图象”一词,往往由于所涉内容的自然性,一般性和抽象含义而采用不加立人傍“亻”的“象”字,例如物理图象,数学图象等。尤其涉...
Perceived Coding Distortion Assessment for Streaming Video
Fuzheng Yang,Shuai Wan,Yilin Chang,Qingpeng Xie
Journal of Multimedia , 2010, DOI: 10.4304/jmm.5.2.118-122
Abstract: For applications involving video streaming, full decoding is usually not acceptable for quality assessment. To address the inherent challenges, an efficient method for coding distortion assessment is proposed in this paper. Building on empirical analysis, the proposed method employs a linear model to assess the coding distortion using the quantization scale. Furthermore, the characteristics of the human visual system are exploited by taking into account the spatial and temporal masking. To estimate the required spatial and temporal complexities in absence of sufficient information, a rate-distortion model is theoretically derived to formulate their relationship with the coding bit-rate. Extensive experimental results have demonstrated the effectiveness of the proposed method for quality assessment with respect to perceived coding distortion.
Two-description distributed video coding for robust transmission
Wang Anhong,Li Zhihong,Zhao Yao,Wang Wubin
EURASIP Journal on Advances in Signal Processing , 2011,
Abstract: In this article, a two-description distributed video coding (2D-DVC) is proposed to address the robust video transmission of low-power capturers. The odd/even frame-splitting partitions a video into two sub-sequences to produce two descriptions. Each description consists of two parts, where part 1 is a zero-motion based H.264-coded bitstream of a sub-sequence and part 2 is a Wyner-Ziv (WZ)-coded bitstream of the other sub-sequence. As the redundant part, the WZ-coded bitstream guarantees that the lost sub-sequence is recovered when one description is lost. On the other hand, the redundancy degrades the rate-distortion performance as no loss occurs. A residual 2D-DVC is employed to further improve the rate-distortion performance, where the difference of two sub-sequences is WZ encoded to generate part 2 in each description. Furthermore, an optimization method is applied to control an appropriate amount of redundancy and therefore facilitate the tuning of central/side distortion tradeoff. The experimental results show that the proposed schemes achieve better performance than the referenced one especially for low-motion videos. Moreover, our schemes still maintain low-complexity encoding property.
Software Optimization of Video Codecs on Pentium Processor with MMX Technology
K. J. Ray Liu,Pohsiang Hsu
EURASIP Journal on Advances in Signal Processing , 2001, DOI: 10.1155/s168761720100018x
Abstract: A key enabling technology for the proliferation of multimedia PC ¢ € s is the availability of fast video codecs, which are the basic building blocks of many new multimedia applications. Since most industrial video coding standards (e.g., MPEG1, MPEG2, H.261, H.263) only specify the decoder syntax, there are a lot of rooms for optimization in a practical implementation. When considering a specific hardware platform like the PC, the algorithmic optimization must be considered in tandem with the architecture of the PC. Specifically, an algorithm that is optimal in the sense of number of operations needed may not be the fastest implementation on the PC. This is because special instructions are available which can perform several operations at once under special circumstances. In this work, we describe a fast implementation of H.263 video encoder for the Pentium processor with MMX technology. The described codec is adopted for video mail and video phone softwares used in IBM ThinkPad.
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