IEEE Transactions on Multimedia

Many video compression algorithms require decisions to be made to select between different coding modes. In the case of H.264, this includes decisions about whether or not motion compensation is used, and the block size to be used for motion compensation. It has been proposed that constrained optimization techniques, such as the method of Lagrange multipliers, can be used to trade off between the ... View full abstract»

Texture compression is an important technique in graphics processing units (GPUs) for saving memory bandwidth. This paper presents a high-quality mipmapping texture compression (MTC) system with alpha maps. Based upon the wavelet transform, a hierarchical approach is adopted for mipmapping textures in the YCbCr color space and alpha channel. By inspecting the similarity between the alpha and lumin... View full abstract»

Face recognition is one of the most intensively studied topics in computer vision and pattern recognition, but few are focused on how to robustly recognize expressional faces with one single training sample per class. In this paper, we modify the regularization-based optical flow algorithm by imposing constraints on some given point correspondences to compute precise pixel displacements and intens... View full abstract»

We present an accurate and robust framework for detecting and segmenting faces, localizing landmarks, and achieving fine registration of face meshes based on the fitting of a facial model. This model is based on a 3-D Point Distribution Model (PDM) that is fitted without relying on texture, pose, or orientation information. Fitting is initialized using candidate locations on the mesh, which are ex... View full abstract»

A novel region-based image fusion framework based on multiscale image segmentation and statistical feature extraction is proposed. A dual-tree complex wavelet transform (DT-CWT) and a statistical region merging algorithm are used to produce a region map of the source images. The input images are partitioned into meaningful regions containing salient information via symmetric alpha-stable (S alphaS... View full abstract»

Omnidirectional videos are usually mapped to planar domain for encoding with off-the-shelf video compression standards. However, existing work typically neglects the effect of the sphere-to-plane mapping. In this paper, we show that by carefully designing the mapping, we can improve the visual quality, stability and compression efficiency of encoding omnidirectional videos. Here we propose a novel... View full abstract»

In this paper we describe the design concepts and prototype implementation of a situation aware ubiquitous computing system using multiple modalities such as National Marine Electronics Association (NMEA) data from Global Positioning System (GPS) receivers, text, speech, environmental audio, and handwriting inputs. While most mobile and communication devices know where and who they are, by accessi... View full abstract»

Automatic detection of (semantically) meaningful audio segments, or audio scenes, is an important step in high-level semantic inference from general audio signals, and can benefit various content-based applications involving both audio and multimodal (multimedia) data sets. Motivated by the known limitations of traditional low-level feature-based approaches, we propose in this paper ... View full abstract»

In this paper, we will propose an automatic music genre classification approach based on long-term modulation spectral analysis of spectral (OSC and MPEG-7 NASE) as well as cepstral (MFCC) features. Modulation spectral analysis of every feature value will generate a corresponding modulation spectrum and all the modulation spectra can be collected to form a modulation spectrogram which exhibits the... View full abstract»

Parts of compressed video streams may be lost or corrupted when being transmitted over bandwidth limited networks and wireless communication networks with error-prone channels. Error concealment (EC) techniques are often adopted at the decoder side to improve the quality of the reconstructed video. Under the conditions of a high rate of data packets that arrives at the decoder corrupted, it is lik... View full abstract»

Without requiring multicast support from the underlying networks, overlay multicast has the advantage of implementing inter-domain multimedia multicast communications. Usually, overlay multicast protocols employ two different topologies: r-ary tree and m-D mesh. In this paper, we study the influence of topology selection on multimedia multicast performance. We present a set of theoretical results ... View full abstract»

Yang proposed the concept of borrow-and-return (BR) to leverage the unused server bandwidth when a group of popular videos being broadcast with the FSFC (first segment on the first channel) broadcasting schemes in order to improve the mean waiting time (MWT) of the viewers with the help of additional receiving bandwidth available at the high-end clients. The BR model borrows the bandwidth of the v... View full abstract»

In this paper, we propose a novel proxy caching scheme for video-on-demand (VoD) services. Our approach is based on the observation that streaming video users searching for some specific content or scene pay most attention to the initial delay, while a small shift of the starting point is acceptable. We present results from subjective VoD tests that relate waiting time and starting point deviation... View full abstract»

In a scenario where each peer of an ad-hoc wireless local area network (WLAN) receives one of many available video streams from a wireless wide area network (WWAN), we propose a network-coding-based cooperative repair framework for the ad-hoc peer group to improve broadcast video quality during channel losses. Specifically, we first impose network coding structures globally, and then select the ap... View full abstract»

Real-time video communication over wireless channels is subject to information loss since wireless links are error-prone and susceptible to noise. Popular wireless link-layer protocols, such as retransmission (ARQ) based 802.11 and hybrid ARQ methods provide some level of reliability while largely ignoring the latency issue which is critical for real-time applications. Therefore, they suffer from ... View full abstract»

We consider the problem of rate allocation among multiple simultaneous video streams sharing multiple heterogeneous access networks. We develop and evaluate an analytical framework for optimal rate allocation based on observed available bit rate (ABR) and round-trip time (RTT) over each access network and video distortion-rate (DR) characteristics. The rate allocation is formulated as a convex opt... View full abstract»

Designing efficient and fair solutions for dividing the network resources in a distributed manner among self-interested multimedia users is recently becoming an important research topic because heterogeneous and high bandwidth multimedia applications (users), having different quality-of-service requirements, are sharing the same network. Suitable resource negotiation solutions need to explicitly c... View full abstract»

Whereas video tells a narrative by a composition of shots, current video retrieval methods focus mainly on single shots. In retrieval performance estimation, similar shots in a narrative may result in performance overestimation. We propose an episode-based version of cross-validation leading up to 14% classification improvement over shot-based cross-validation. View full abstract»

Next-generation wireless communication systems aim at supporting wireless multimedia services with different quality-of-service (QoS) and bandwidth requirements. Therefore, effective management of the limited radio resources is important to enhance the network performance. In this paper, we propose a QoS adaptive multimedia service framework for controlling the traffic in multimedia wireless netwo... View full abstract»