interframe coding techniques, such as those used in MPEG video, give rise to a sequence of encoded pictures whose sizes (in number of bits) differ by a factor of ten or more, Buffering is needed to reduce fluctuations...
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interframe coding techniques, such as those used in MPEG video, give rise to a sequence of encoded pictures whose sizes (in number of bits) differ by a factor of ten or more, Buffering is needed to reduce fluctuations in the rate at which video packets are sent to a network connection, In this paper, we design and specify a lossless smoothing algorithm, characterized by three parameters: D (delay bound), K (number of pictures with known sizes), and H (lookahead interval), We prove a theorem which guarantees that, if K greater than or equal to 1, the algorithm finds a solution that satisfies the delay bound, We present the algorithm's performance from a large number of experiments conducted using MPEG video traces, Lastly, we discuss algorithm implementation.
Some digital source coding techniques for speech and video are reviewed. Predictive coding of speech, multipulse and code-excited coders and frequency-domain coders are discussed and compared for the coding of speech ...
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Some digital source coding techniques for speech and video are reviewed. Predictive coding of speech, multipulse and code-excited coders and frequency-domain coders are discussed and compared for the coding of speech signals, and intraframe and still image coding and interframe coding are examined for the coding of image and video signals. The emphasis is on those algorithms that offer high compression while maintaining the perceptual quality of the source signals are discussed. Some algorithms that are general waveform coding algorithms and do not strictly depend on the input source are included
This paper deals with the basic requirements that should be fulfilled by a technique for segmenting video sequences in coding applications. The specific problems of coding-oriented video segmentation are analyzed. Thi...
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This paper deals with the basic requirements that should be fulfilled by a technique for segmenting video sequences in coding applications. The specific problems of coding-oriented video segmentation are analyzed. This way intra-frame and inter-frame segmentation approaches are studied. In the inter-frame mode, the problems of temporal label coherence and connectivity in the coding framework are discussed and solutions are presented.
We first present an overview of the MPEG-4 video standard and its relationship to other existing as well as evolving video standards. MPEG-4 video, while introducing a new paradigm of treating each object in a scene i...
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ISBN:
(纸本)0819427497
We first present an overview of the MPEG-4 video standard and its relationship to other existing as well as evolving video standards. MPEG-4 video, while introducing a new paradigm of treating each object in a scene independently, utilizes the traditional motion compensated DCT framework for coding of each object. Thus, while introducing new object based coding functionality, it is also capable of providing traditional frame-based coding. Furthermore, it supports advanced functionalities such as efficient coding of background as a sprite, robustness to channel errors, spatial and temporal scalability of arbitrary shape objects etc. Next, we evaluate the statistical performance of the MPEG-4 video under a number of selected conditions and compare it, depending on the application, with the H.263, the MPEG-I and the MPEG-2 standards. For each traditional application, based on our limited set of experiments, MPEG-4 video appears to provide equal or better performance when compared to the most suitable existing standard addressing that application area. For the new object based applications, although MPEG-4 video when coding arbitrary shaped objects, incurs additional coding cost, perhaps with further optimization, the increased cost may be offset by improved tradeoffs in coding quality control, channel bandwidth and decoding resource adaptations.
In recent years, Virtual Reality (VR) and Augmented Reality (AR) applications have seen a drastic increase in commercial popularity. Different representations have been used to create 3D reconstructions for AR and VR....
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ISBN:
(纸本)9781538663042
In recent years, Virtual Reality (VR) and Augmented Reality (AR) applications have seen a drastic increase in commercial popularity. Different representations have been used to create 3D reconstructions for AR and VR. Point clouds are one such representation that are characterized by their simplicity and versatility, making them suitable for real time applications. However, point clouds are unorganized and identifying redundancies to use for compressing them is challenging. For the compression of time varying or dynamic sequences it is critical to identify temporal redundancies that can be used to describe predictors and further compress streams of point clouds. We use a point cloud codec that encodes additional information in an enhancement layer. We propose adding inter prediction to the enhancement layer in order to gain further bit rate savings.
We report on recent advances in traditional DCT based video coding at low bitrates. These improvements allow either an increase in coding efficiency or an increase in other functionalities. Our investigation is conduc...
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ISBN:
(纸本)0819424358
We report on recent advances in traditional DCT based video coding at low bitrates. These improvements allow either an increase in coding efficiency or an increase in other functionalities. Our investigation is conducted within the framework of the ongoing work towards the MPEG-4 video standard. The ISO Moving Picture Experts Group (MPEG) is currently developing this standard after having completed the MPEG-I and the MPEG-2 standards. The MPEG-4 video standard is addressing a number of content based as well as traditional functionalities. The development process consists of iterative refinement of the Verification Model (which describes the coding method) via a set of well defined core experiments. Our first experiment is on improved coding efficiency of Intra and uses DC and AC predictions and optimized scanning of DCT coefficients followed by a separate optimized variable length code table. Our second experiment is the study of bidirectional coding to allow additional functionality such as temporal scalability at low bit-rates. We present results of these experiments and summarize our findings.
Emerging multimedia applications have created the need for new functionalities in digital communications. Whereas existing compression standards only deal with the audio-visual scene at a frame level, it is now necess...
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Emerging multimedia applications have created the need for new functionalities in digital communications. Whereas existing compression standards only deal with the audio-visual scene at a frame level, it is now necessary to handle individual objects separately, thus allowing scalable transmission as well as interactive scene recomposition by the receiver. The future MPEG-4 standard aims at providing compression tools addressing these functionalities. Unlike existing frame-based standards, the corresponding coding schemes need to encode shape information explicitly. This paper reviews existing solutions to the problem of shape representation and coding. Region and contour coding techniques are presented and their performance is discussed, considering coding efficiency and rate-distortion control capability, as well as flexibility to application requirements such as progressive transmission, low-delay coding, and error robustness.
The recent H.264/AVC video coding standard provides a higher coding efficiency than previous standards. H.264/AVC achieves a bit rate saving of more than 50% with many new technologies, but it shows very heavy computa...
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The recent H.264/AVC video coding standard provides a higher coding efficiency than previous standards. H.264/AVC achieves a bit rate saving of more than 50% with many new technologies, but it shows very heavy computational complexity. In this paper, a fast mode decision scheme for interframe coding is proposed to reduce the computational complexity for H.264/AVC video encoding system. To reduce the block mode decision complexity in interframe coding, we use the contextual information based on the co-located and neighboring macroblocks (MBs) to detect a proper MB that can be stopped early. Then, for the current MB, a priority information of the context is suggested for adding more mode types adaptively. The proposed algorithm shows the average speed-up factors of 59.11 to 77.41% for various sequences with a negligible bit increment and a minimal loss of image quality, in JM reference softwares. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3647552]
We revisit the classic problem of developing a correlation model for natural videos and studying their theoretical rate distortion bounds. We propose the correlation coefficient of two pixels in two nearby video frame...
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ISBN:
(纸本)9781424429257
We revisit the classic problem of developing a correlation model for natural videos and studying their theoretical rate distortion bounds. We propose the correlation coefficient of two pixels in two nearby video frames as the product of the spatial correlation coefficient of these two pixels, as if they were in the same frame, and a variable to quantify the temporal correlation between these two video frames. The spatial correlation model for pixels within one video frame is a conditional correlation model. The conditioning is on local texture and the optimal parameters can be calculated for a specific video with a mean absolute error (MAE) usually smaller than 5%. We use this conditional correlation model to calculate the conditional rate distortion function when universal side information on local texture is available at both the encoder and the decoder. We demonstrate that this side information, when available, can save as much as 1 bit per pixel for a single video frame and 0.7 bits per pixel for multiple video frames. This rate distortion bound with local texture information taken into account while making no assumptions on coding, is shown indeed to be a valid lower bound with respect to the operational rate distortion curves of both intra-frame and inter-frame coding in AVC/H.264.
Medical image compression is unavoidable due to large amount of storage space or high bandwidth for communication in its original form. In hospitals sequence of images are produced which are much correlated. Hence los...
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ISBN:
(纸本)9781467349215
Medical image compression is unavoidable due to large amount of storage space or high bandwidth for communication in its original form. In hospitals sequence of images are produced which are much correlated. Hence lossless image compression technique is required. To exploit the correlation a new algorithm is proposed in- this paper. The proposed compression method combines Super-Spatial Structure Prediction with interframe coding to achieve higher compression ratio. Initially the Super-Spatial Structure Prediction algorithm is applied with the fast block-matching process which includes Diamond Search method. To further increase the compression ratio we propose a new scheme Head Code Compression. Experimental results of our proposed Composite algorithm for medical image sequences achieve 25% more reduction than the prior arts.
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