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Fractional motion estimation (FME) is widely used in video compression standards. In H.264/AVC, the precision of motion vector is down to quarter pixels to improve the coding efficiency. However, FME occupies over 45% of the computation complexity in an H.264 encoder and this high complexity limits the processing capability. In this paper, a single-iteration full search FME is proposed. By the algorithm...
H.264 adopts variable block size motion estimation and rate-distortion-optimization based mode decision to improve video quality and compression ratio. These techniques have made H.264 better than other existing video coding standards. However, they are computationally intensive and time-consuming. In this paper, a fast mode selection scheme is proposed for H.264 inter prediction. Firstly, the first...
Motion estimation is a very time consuming part in H.264 codec. In order to reduce motion estimation time, many strategies have been used during this process. Dynamic search range is one of them. In this paper, based on the analysis of the problems existed in current algorithm, we propose a new strategy to predict motion estimation search range by using the information of image size, block mode and...
In modern video coding standards, motion compensated prediction (MCP) plays a key role to achieve video compression efficiency. Most of them make use of block matching techniques and assume the motions are pure translational. Attempts toward a more general motion model are usually too complex to be practical in near future. In this paper, a new Block-Matching Translation and Zoom Motion-Compensated...
In this paper, we contribute a configurable SAD tree architecture based on adaptive subsampling scheme. Firstly, by further exploiting the spatial feature, the integer motion estimation process is greatly sped up. Secondly, the conventional partial sum of absolute difference (SAD) based pipeline structure is optimized into configurable SAD oriented way, which enhances the performance and solve the...
This paper proposes a novel fractional compensation approach for spatial scalable video coding. It simultaneously exploits inter layer correlation and intra layer correlation by learning-based mapping. Instead of using an enhancement layer reconstruction as an entire reference, a set of reference pairs are generated from high-frequency components of both base layer and enhancement layer reconstructions...
In the H.264/AVC coding standard, motion estimation (ME) is allowed to use multiple reference frames to make full use of reducing temporal redundancy in a video sequence. Although it can further reduce the motion compensation errors, it introduces tremendous computational complexity as well. In this paper, we propose a statistical learning approach to reduce the computation involved in the multireference...
In this paper, we propose a fast multi-layer motion estimation algorithm for spatial scalability provided in H.264/AVC scalable extension, based on the reuse of the motion vectors from multiple spatial layers. The reused motion vector is used to set a search center and refined within a small search area. However, the reused motion vector often produces significant prediction error at object boundaries...
Motion estimation process is the most computational and memory intensive component in video encoders. However, traditional motion estimation algorithms focus on rate and distortion performance and do not take memory bandwidth into consideration. As a result, its performance will be degraded under bandwidth constraint environment. In this paper, a bandwidth-rate-distortion optimized motion estimation...
Distributed video coding (DVC), has been an interesting alternative to the conventional video coding for a number of applications because of its flexibility for designing extremely low complexity video encoders. The performance of DVC can be improved by only modifying the decoder to keep the encoder complexity at the same level. In this paper, we propose a novel modified framework for a DVC codec...
In this paper based on statistical analysis performed on a number of video sequences with different motion characteristics, we show that strong correlation exists between the direction of motion of a block and those of its neighboring blocks. Secondly, we show that a block moves in the same direction as a neighboring block that its prediction vector produces least distortion. Based on these findings...
The H.264/AVC standard achieves a high coding efficiency compared with previous standards. However, it does so at a very high computational cost, with motion estimation being one of the most demanding subsystems. In this paper a hierarchical classification-based approach to the inter mode decision (MD) problem is proposed. A first classifier detects SKIP/Direct modes while a second one is able to...
Scalable video coding (SVC) is the ongoing standard as an extension of H.264/AVC to provide stable multimedia services to various service environments and end systems. An exhaustive block motion estimation has been used to determine the best coding mode for each block type in this standard. This achieves a high coding efficiency; however it causes very high computational complexity in the encoding...
This paper presents a new algorithm for moving object detection in the H.264/AVC compressed domain which relies on motion vector information. In contrast to other motion vector-based algorithms, special attention is paid to noisy motion vectors as they highly decrease the performance of these algorithms. We propose to estimate the reliability of motion vectors by comparing them with projected motion...
Conventional rate-distortion (RD) optimized video coding is formulated for an error-free environment. Special considerations have to be made when transmitting video in lossy networks. In this paper we demonstrate a novel method of weighting the distortion used for mode decisions and motion estimation in H.264. By determining an appropriate weighting factor, motion vectors are biased towards macroblocks...
High external memory bandwidth requirement is one major challenge for efficient hardware motion estimation (ME) implementation. Large double-buffered on-chip search window (SW) buffer is usually employed to increase the throughput. In this paper, we focus on SW buffer structure optimization in a systematic viewpoint. An efficient buffer share mechanism is proposed to minimize the memory consumption,...
In mobile-to-mobile video communications, both the sender and the receiver devices should not have higher complexity requirements to perform complex video compression tasks. The traditional video coding solutions are not suitable to support this communications due to its extremely complex encoding algorithm. On the other hand, the new Wyner-Ziv video coding paradigm reduces the complexity of the encoder...
We address the problem of recognizing, in dynamic meetings in which people do not remain seated all the time, the visual focus of attention (VFOA) of seated people from their head pose and contextual activity cues. We propose a model that comprises the VFOA of a meeting participant as the hidden state, and his head pose as the observation. To account for the presence of moving visual targets due to...
In this paper we propose to show how signal processing algorithm designers can understand the nuances of multicore computing engines in order to conveniently exploit these powerful devices. This is illustrated by presenting source and channel coding, two fundamental operations in multimedia signal processing. We describe methods and principles to develop parallel signal processing algorithms to compute...
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