The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper considers the use of punctured quasi-arithmetic (QA) codes for the Slepian-Wolf problem. These entropy codes are defined by finite state machines for memory-less and first-order memory sources. Puncturing an entropy coded bit-stream leads to an ambiguity at the decoder side. The decoder makes use of a correlated version of the original in order to remove this ambiguity. A complete DSC scheme...
Depth image-based rendering (DIBR) is generally used to synthesize virtual view images in free viewpoint television (FTV) and three-dimensional (3-D) video. One of the main problems in DIBR is how to fill the holes caused by disocclusion regions and inaccurate depth values. In this paper, we propose a new hole filling method using a depth based in-painting technique. Experimental results show that...
Decoder-side motion vector derivation (DMVD) using template matching has been shown to improve coding efficiency of H.264/AVC based video coding. Instead of explicitly coding motion vectors into the bitstream, the decoder performs motion estimation in order to derive the motion vector used for motion compensated prediction. In previous works, DMVD was performed using a full template matching search...
Fast and accurate block-based motion estimation (BME) is desired in many video coding systems. By conducting block matching in lower dimensional projection space, followed by candidate exclusion through thresholding, projection-based BME (PBME) methods can run several times faster than the exhaustive full search method, with little loss in accuracy. In PBME methods, the appropriate choice of threshold...
In this paper, we propose a scheme for the robust transmission of video in error prone environments using multiple description coding (MDC) based on the scalable video coding extension (SVC) of H.264/AVC. Due to the layer structure of SVC, a base layer is referenced by one or more enhancement layers. The proposed method produces multiple description base layers to achieve robust video communication...
In this paper, a calculation method of transform directions for adaptive directional wavelet transform (AD WT) is proposed. It uses 2-D highpass filters as a preprocessing of the conventional calculation stage. The filters can reduce the number of direction candidates effectively. In image coding, our proposed framework shows very comparable results to the conventional AD WT and outperforms the traditional...
Most commercial digital still cameras use a single sensor array (e.g., CMOS or CCD) with color filter array (CFA) to reduce the cost and size. Since the image obtained with CFA has only one color value per pixel, the demosaicing is needed to acquire missing two color values. Although many demosaicing methods have been proposed, they still have artifacts such as rainbow and zippering artifact. In this...
This paper analyzes two variants of principal component analysis (PCA) for error-concealment: blockwise PCA and clustered blockwise PCA. Realistic communication channels are not error free. Since the signals transmitted on real-world channels are highly compressed, regardless of cause, the quality of images reconstructed from any corrupted data can be very unsatisfactory. Error concealment is intended...
The H.264/AVC standard employs a number of error-resilient mechanisms to correct transmission errors. These methods assume a packet-loss scenario, where all the macroblocks (MBs) contained within a corrupted slice are dropped and concealed. However, most of the MBs contained within corrupted slices provide minimal (if any) visual distortions and therefore concealing them causes a superfluous drop...
This paper proposes an improved intra prediction method for H.264/AVC. The conventional method uses only adjoining pixels as reference pixels. The residual energy is increased if the decoded pixels are occluded, which would result in low coding efficiency. In addition, the conventional prediction method copies the same weighted prediction value to several of the pixels lying in the prediction direction...
This paper presents an adaptation of peer-to-peer diffusion strategies of video over mobile links based on the use of multiple description coding. The system architecture, including the used overlay algorithm (the unstructured GIA algorithm) and video coding with multiple description coding (MDC), are presented as well as their interest in this context. Simulation results illustrate the approach,...
This paper presents a novel architecture for the secure delivery of encrypted H.264 SVC bitstreams. It relies on a block cipher and stream cipher used in a novel way that would allow an intermediary transcoder to truncate the bitstream to the appropriate bit-rate without decrypting the data. The system, called SVC-sec, is compared to other architectures presented in the literature and it is shown...
In this work, we investigate a working memory approach for efficient temporal prediction in H.264 video coding. After video frames are encoded, objects are extracted, analyzed, and indexed in a dynamic database which acts as a working memory for the H.264 video encoder. During the encoding process, objects with similar spatial characteristics are retrieved from the working memory and used for motion...
It is well-known that large depth-coding errors typically occurring around depth edge areas lead to distorted object boundaries in the synthesized texture images. This paper proposes a multi-layered coding approach for depth images as a complement to the popular edge-aware approaches such as those based on platelets. It is shown that guaranteeing a near-lossless bound on the depth values around the...
Firstly the paper reports experimental results proving that Cascaded Pixel Domain Transcoder (CPDT) is extremely inefficient when used for AVC/H.264 bitstream transcoding aimed at bitrate reduction not exceeding 30% of primary bitrate. In the paper, proposed is a transcoder that exploits structured truncation of bitsream and an algorithm for such truncation is described. The experimental results are...
State-of-the-art video compression standards such as H.264 employ tree-structured motion compensation by splitting macro-blocks into fixed square or rectangular sub-blocks. Although, this approach leads to improved compression performance, recent studies have shown that further gain can be achieved via slicing blocks with arbitrary line segments to better match the boundaries between moving objects...
This paper proposes a novel, fast, highly-parallel and configurable architecture for zigzag scan and optional scans in multiple video coding standards, including H.261, MPEG-1,2,4, H.264/AVC, and AVS. Arbitrary scan patterns could be supported by configuring the ROM data, and the proposed architecture can largely reduce the processing cycles. This makes it possible to integrate the scan unit into...
We investigate coding tools for interactive multiview streaming (IMVS), where clients interactively request desired views for successive video frames, and in response the server sends the appropriate pre-compressed video data to the clients. Solution based on using only I-frames to support view switching would incur high transmission cost, while for that based on using only P-frames to encode every...
In this work we consider the design of the lifting filters and trees used in a separable tree-based wavelet transform. We first consider the use of improved prediction filters, optimized to represent more efficiently smooth signals for arbitrary tree structures. We then consider the design of update filters that are orthogonal to neighboring prediction operators. While the corresponding decomposition...
This paper presents a rate control (RC) algorithm for the scalable extension of the H.264/AVC video coding standard. The proposed rate controller is designed for real-time video streaming with buffer constraint. Since a large buffer delay and bit rate variation are allowed in this kind of applications, our proposal reduces the quantization parameter (QP) fluctuation to provide consistent visual quality...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.