Jiangchuan Liu

Image Compression Standards

Recent years have seen an explosion in the availability of digital images. In this chapter, we examine some current image compression standards and demonstrate how techniques presented in Chaps. 7 and 8 are applied in practice. We first describe how transform coding based on DCT (Discrete Cosine Transform), quantization, and entropy coding are explored in the standard JPEG, used in most images, then go on to look at the wavelet-based JPEG2000 standard. Two other standards, JPEG-LS—aimed particularly at a lossless JPEG, outside the main JPEG standard—and JBIG, for bilevel image compression, are included for completeness.

New Video Coding Standards: H.264 and H.265

We introduced basic video compression techniques in Chaps. 10 and 11. We examined the ideas behind the MPEG standards, starting with MPEG-1, 2, and then MPEG-4, and 7. In this chapter, we introduce the newer video compression standards H.264 and H.265. For efficiency, integer transform is adopted in the place of the Discrete Cosine Transform (DCT). Other new features include quarter-pixel accuracy in motion vectors, predictive coding in intra frames, in-loop deblocking filtering, and Context-Adaptive Binary Arithmetic Coding (CABAC). Moreover, H.265 also facilitates parallel processing. With their superior compression performance over H.263 and MPEG-2, H.264 and H.265 are currently the leading candidates to carry a whole range of video contents on many potential applications.

Cloud Computing for Multimedia Services

The emergence of cloud computing has dramatically changed the service models for modern computer applications. Utilizing elastic resources in powerful data-centers, it enables end users to conveniently access computing infrastructure, platforms, and software provided by remote cloud providers (e.g., Amazon, Google, and Microsoft) in a pay-as-you-go manner or with long-term lease contracts. This new generation of computing paradigm, offering reliable, elastic, and cost-effective resource provisioning, can significantly mitigate the overhead for enterprises to construct and maintain their own computing, storage, and network infrastructures. It has provided countless new opportunities for both new and existing applications. In this chapter, we provide an overview of cloud computing, focusing on its impact on multimedia services. We then discuss multimedia content sharing with cloud storage and multimedia computation offloading to the cloud. We also use cloud gaming as a case study to examine the role of the cloud in the new generation of interactive multimedia services.

Social Media Sharing

Social media, a group of Internet-based applications that build on the ideological and technological foundations of Web 2.0, allow the creation and exchange of user-generated content. With the pervasive penetration of wireless mobile networks, the advanced development of smartphones and tablets, and the massive market of mobile applications, social media contents can now be easily generated and accessed at any time and anywhere. They have substantially changed the way organizations, communities, and individuals communicate.

Lossless Compression Algorithms

In this chapter, data compression as it relates to multimedia information is studied from the point of view of lossless algorithms, where the input data is essentially exactly recoverable from the compressed data Lossy algorithms, for which this is not the case, are presented in Chapter 8. Here we introduce the fundamentals of information theory and algorithms whose goal is a savings in bitrate given the entropy, especially Huffman Coding and its adaptive version. We then study Dictionary-based Coding (as in Winzip) and go on to a detailed discussion of Arithmetic Coding. Finally, Lossless Image Compression is examined specifically.

A Taste of Multimedia

In Chapter 2, we introduce a set of tasks and concerns that are considered in studying multimedia, from the point of view of a technically comfortable reader. When it comes to multimedia production and presentation, the issues of graphics styles fonts are discussed, with some surprising conclusions. To provide a further “taste” of multimedia, we show how simple animations may proceed. To round out the discussion of such tasks, we consider a “build your own” video-transition problem, where the intent would be to generate one’s own video transition. We then go on to review the current and future state of multimedia sharing and distribution, outlining later discussions of social media, video sharing, and new forms of TV. Finally, the details of some popular multimedia tools are set out for a quick start into the field.

Content-Based Retrieval in Digital Libraries

This chapter is concerned with finding images or video from (possibly very large) collections of these. Each type of modality in multimedia information, e.g., text and image, provides its own type of semantic information to help in search for content. That is, text-based search is bolstered by information in images and video, from low-level features to high-level semantic content. In this book we focus only on techniques and systems that make use of image features themselves, without text, to retrieve images or video from databases or from the web. Detail is provided on specific features useful to this purpose. Search engines devised on these features are said to be content based: the search is guided by image similarity measures based on the statistical content of each image. At a higher semantic level,action recognition in video is also examined in some detail.

Multimedia Over Wireless and Mobile Networks

The rapid developments in computer and communication technologies have made ubiquitous computing a reality. From cordless phones in the early days to later cellular phones, wireless mobile communication has been the core technology that enables anywhere and anytime information access and sharing. The new generation of smart mobile devices that emerged only in recent years are driving the revolution further. Multimedia over wireless and mobile networks share many similarities as over the wired Internet; yet the unique characteristics of wireless channels and the frequent movement of users also pose new challenges that must be addressed. This chapter reviews wireless channel characteristics, and describes representative wireless technologies for wide-area cellular networks (from 1G to 4G) and local area networks (WiFi and Bluetooth). We then examine the key issues for multimedia over wireless networks, including error detection and correction, error-resilient coding, error concealment, and re-synchronization. Finally, we examine mobility management, including both the network layer mobile IP and the link layer handoff.

Fundamental Concepts in Video

In this chapter, we introduce the principal notions needed to understand video. Here we consider the following aspects of video and how they impact multimedia applications: (1) Analog video; (2) Digital video; (3) Video display interfaces; (4) 3D video. Knowledge of video must include historically important standards in Analog Video. Digital Video has different ideas emphasized, and we go on to look at HDTV as well as Ultra High Definition TV. After a discussion of Video Display Interfaces, we enter into the new and exciting field of 3D Video and TV.

MPEG Video Coding: MPEG-1, 2, 4, and 7

In this chapter, we examine the ideas behind the MPEG standards, starting with MPEG-1, -2, and then MPEG-4, and 7. In MPEG-1 and -2, bidirectional search for motion vectors is introduced. Interlaced video and high-definition TV (HDTV) are supported in MPEG-2. Moreover, it supports various scalable codings such as SNR, spatial, temporal, and their combination. MPEG-4 and -7 studied the issue of video coding based on video objects. Although the visual object-based video representation and compression approach developed in MPEG-4 and 7 have not been commonly used in current popular standards such as H.264 and H.265, it has great potential to be adopted in the future when the necessary Computer Vision technology for automatic object detection becomes more readily available.