A Framework for MPEG‐4 Contents Delivery over DMB

Digital Multimedia Broadcasting (DMB) is an upcoming standard in Korea used to provide mobile multimedia broadcasting service based on the Eureka‐147 Digital Audio Broadcasting (DAB) system. The current dominant multimedia coding standard, MPEG‐4, is foreseen to play an important role in forthcoming DMB services. However, the current approaches for transporting MPEG‐4 content over DMB networks are not optimized. To address this issue we propose a novel MPEG‐4 stream multiplexer, called M4SMux, which provides better stream multiplexing and delivery over DMB networks. M4SMux features an MPEG‐4 elementary‐stream interleaving mechanism that reduces the multiplexing overhead and a multiplex configuration mechanism that utilizes M4SLinkTable for easy content access. In addition, we propose an error correction method which enhances transport efficiency.     

A Novel Method for Inserting an MPEG‐2 TS into Ensemble in a DMB Transmission System

This paper presents an effective algorithm for inserting an MPEG‐2 transport stream (TS) into a Digital Audio Broadcasting (DAB) ensemble without any bandwidth waste in a Digital Multimedia Broadcasting (DMB) transmission system. The key technologies of this algorithm include packet rate control and program clock reference correction, which are important for TS processing. The proposed algorithms are applied to the various DMB transmission systems based on Eureka‐147, and the performance of the proposed algorithm is confirmed through the experimental DMB broadcasting.     

Design of Middleware for Interactive Data Services in the Terrestrial DMB

In this letter, we introduce a new middleware architecture and its generic application programming interface (API) (called the T‐DMB MATE API) for terrestrial digital multimedia broadcasting (T‐DMB). Middleware in T‐DMB enables inter‐operable applications to be downloaded from both broadcast and telecommunication networks in advance and to be executed in any type of T‐DMB receiver. The middleware we introduce here is especially designed to support a proposed method for application provisions applied to a concept of application module appropriate to the service environment of T‐DMB. We also verify the designed T‐DMB MATE API through the implementation of the middleware and its application in a PC‐based receiver.     

Efficient Generation of Scalable Transport Stream for High Quality Service in T‐DMB

We introduce an advanced terrestrial digital multimedia broadcasting (AT‐DMB) system that overcomes the limitation of data transmission rates of T‐DMB by doubling it with the same frequency bandwidth. In this letter, we propose an efficient algorithm which generates a scalable transport stream in AT‐DMB by multiplexing certain types of elementary streams encoded using scalable video coding and an MPEG‐surround audio coder for high‐quality multimedia services.     

An MPEG‐4 Compliant Interactive Multimedia Streaming Platform Using Overlay Networks

This paper presents a multimedia streaming platform for efficiently transmitting MPEG‐4 content over IP networks. The platform includes an MPEG‐4 compliant streaming server and client, supporting object‐based representation of multimedia scenes, interactivity, and advanced encoding profiles defined by the ISO standard. For scalability purposes, we employ an application‐layer multicast scheme for media transmission using overlay networks. The overlay network, governed by the central entity of the network distribution manager, is dynamically deployed according to a set of pre‐defined criteria. The overlay network supports both broadcast delivery and video‐on‐demand content. The multimedia streaming platform is standards‐compliant and utilizes widespread multimedia protocols such as MPEG‐4, real‐time transport protocol, real‐time transport control protocol, and real‐time streaming protocol. The design of the overlay network was architected with the goal of transparency to both the streaming server and the client. As a result, many commercial implementations that use industry‐standard protocols can be plugged into the architecture relatively painlessly and can enjoy the benefits of the platform.     

Broadcasting System Compliant with MPEG‐2/4 IPMPX

In this paper, we present an intellectual property management and protection (IPMP) system in a broadcasting environment to provide mechanisms for copyright and contents protection that are compliant with the MPEG‐2 and MPEG‐4 IPMP Extension (IPMPX) specifications. The technology for processing IPMP related information was exploited, and a terminal model has been successfully designed and implemented. In addition, interoperability, which is the main objective of MPEG‐2/4 IPMPX, has been addressed in detail. The experimental results show that the implemented system performs the IPMP process well, meeting the requirements of a broadcasting environment.     

我国数字音频广播和数字多媒体广播的发展

本文介绍了国外数字音频广播（DAB）发展的历史,阐述了我国DAB三个发展阶段,提出随着技术不断的发展,DAB必须将注入新的内容,获得新的发展,它将逐渐发展为集声音、视频和数据于一体的数字多媒体广播（DMB）,成为新一代广播媒体形式。     

Disparity‐Compensated Stereoscopic Video Coding Using the MAC in MPEG‐4

The MPEG‐4 multiple auxiliary component (MAC) is a good mechanism to achieve one‐stream stereoscopic video coding. However, there is no syntax or semantics for the residual texture data of the disparity‐compensated image in the current MAC. Therefore, we propose a novel disparity‐compensated coding method using the MAC for stereoscopic video. We also define a novel MAC semantics in MPEG‐4 so as to support the proposed coding algorithm. The major difference between the existing and proposed coding methods using the MAC is the addition of the residual texture coding.     

Hardware‐Software Implementation of MPEG‐4 Video Codec

This paper presents an MPEG‐4 video codec, called MoVa, for video coding applications that adopts 3G‐324M. We designed MoVa to be optimal by embedding a cost‐effective ARM7TDMI core and partitioning it into hardwired blocks and firmware blocks to provide a reasonable tradeoff between computational requirements, power consumption, and programmability. Typical hardwired blocks are motion estimation and motion compensation, discrete cosine transform and quantization, and variable length coding and decoding, while intra refresh, rate control, error resilience, error concealment, etc. are implemented by software. MoVa has a pipeline structure and its operation is performed in four stages at encoding and in three stages at decoding. It meets the requirements of MPEG‐4 SP@L2 and can perform either 30 frames/s (fps) of QCIF or SQCIF, or 7.5 fps (in codec mode) to 15 fps (in encode/decode mode) of CIF at a maximum clock rate of 27 MHz for 128 kbps or 144 kbps. MoVa can be applied to many video systems requiring a high bit rate and various video formats, such as videophone, videoconferencing, surveillance, news, and entertainment.     

An Efficient Transmission Scheme of MPEG2‐TS over RTP for a Hybrid DMB System

Hybrid digital multimedia broadcasting (DMB) is a next‐generation mobile TV system that combines broadcasting and wireless communication networks and can provide various high‐quality multimedia services. However, if a system adheres to the current standard of transmitting the DMB content in the form of MPEG2‐TS through wireless networks, it results in a burden on the network due to low transmission efficiency. The reasons for the low transmission efficiency are as follows. First, due to its constant bitrate characteristic, DMB MPEG2‐TS includes a considerable amount of needless information, such as NULL packets and stuffing bytes. Second, due to the inflexibility of the Real‐time Transport Protocol (RTP) standard, one cannot fully utilize the maximum transmission unit of the network when converting MPEG2‐TS to RTP stream for transmission. This paper proposes a new transmission scheme that resolves these problems. Experiment results show that the proposed scheme improves data bitrate transmission efficiency by 8% to 36%, compared to the standard scheme, in the streaming of various real‐DMB contents.     

Design of AT‐DMB Baseband Receiver SoC

This paper presents the design of an advanced terrestrial digital multimedia broadcasting (AT‐DMB) baseband receiver SoC. The AT‐DMB baseband is incorporated into a hierarchical modulation scheme consisting of high priority (HP) and low priority (LP) stream decoders. The advantages of the hierarchical modulation scheme are backward compatibility and an enhanced data rate. The structure of the HP stream is the same as that of the conventional T‐DMB system; therefore, a conventional T‐DMB service is possible by decoding multimedia data in an HP stream. An enhanced data rate can be achieved by using both HP and LP streams. In this paper, we also discuss a time deinterleaver that can deinterleave data for a time duration of 384 ms or 768 ms. The interleaving time duration is chosen using the LP symbol mapping scheme. Furthermore, instead of a Viterbi decoder, a turbo decoder is adopted as an inner error correction system to mitigate the performance degradation due to a smaller symbol distance in a hierarchically modulated LP symbol. The AT‐DMB baseband receiver SoC is fabricated using 0.13 µm technology and shows successful operation with a 50 mW power dissipation.     

Low‐Complexity MPEG‐4 Shape Encoding towards Realtime Object‐Based Applications

Although frame‐based MPEG‐4 video services have been successfully deployed since 2000, MPEG‐4 video coding is now facing great competition in becoming a dominant player in the market. Object‐based coding is one of the key functionalities of MPEG‐4 video coding. Realtime object‐based video encoding is also important for multimedia broadcasting for the near future. Object‐based video services using MPEG‐4 have not yet made a successful debut due to several reasons. One of the critical problems is the coding complexity of object‐based video coding over frame‐based video coding. Since a video object is described with an arbitrary shape, the bitstream contains not only motion and texture data but also shape data. This has introduced additional complexity to the decoder side as well as to the encoder side. In this paper, we have analyzed the current MPEG‐4 video encoding tools and proposed efficient coding technologies that reduce the complexity of the encoder. Using the proposed coding schemes, we have obtained a 56 percent reduction in shape‐coding complexity over the MPEG‐4 video reference software (Microsoft version, 2000 edition).     

Audio Transcoding for Audio Streams from a T‐DTV Broadcasting Station to a T‐DMB Receiver

We propose an efficient audio transcoding algorithm that can convert audio streams from terrestrial digital television broadcasting service stations to those for terrestrial digital multimedia broadcasting hand‐held receivers. The proposed algorithm avoids the complicated psychoacoustic analysis by calculating the scalefactors of the bit‐sliced arithmetic coding encoder directly from the signal‐to‐noise ratio parameters of the AC‐3 decoder. The bit‐allocation process is also simplified by cascading the nested distortion control loop. Through subjective evaluation, it is shown that the proposed algorithm provides comparable audio quality to tandem coding but it requires much smaller complexity.     

Improving the Reception Performance of Legacy T‐DMB/DAB Receivers in a Single‐Frequency Network with Delay Diversity

This paper describes a simple delay diversity technique for terrestrial digital multimedia broadcasting (T‐DMB) and digital audio broadcasting in a single‐frequency network (SFN). For the diversity technique, a delay diversity scheme is adopted. In the delay diversity scheme, a non‐delayed signal is transmitted in the first antenna, and delayed versions of the signal are transmitted in each additional antenna. For an SFN environment with multiple transmitters, delay diversity can be executed by controlling the emission times of the transmitters. This SFN delay diversity scheme does not require any hardware changes in either the transmitter or receiver, and perfect backward compatibility can be acquired. To evaluate the performance improvement, laboratory tests are executed with various types of commercial T‐DMB receivers as well as a measurement receiver. The improvement in the bit error rate performance is evaluated using a measurement receiver, and an improvement of the threshold of visibility value is evaluated for commercial receivers. Test results show that the T‐DMB system can obtain diversity gain using the described technique.     

A Subthreshold CMOS RF Front‐End Design for Low‐Power Band‐III T‐DMB/DAB Receivers

This letter presents a CMOS RF front‐end operating in a subthreshold region for low‐power Band‐III mobile TV applications. The performance and feasibility of the RF front‐end are verified by integrating with a low‐IF RF tuner fabricated in a 0.13‐μm CMOS technology. The RF front‐end achieves the measured noise figure of 4.4 dB and a wide gain control range of 68.7 dB with a maximum gain of 54.7 dB. The power consumption of the RF front‐end is 13.8 mW from a 1.2 V supply.     

Performance Analysis for MPEG‐4 Video Codec Based on On‐Chip Network

In this paper, we present a performance analysis for an MPEG‐4 video codec based on the on‐chip network communication architecture. The existing on‐chip buses of system‐on‐a‐chip (SoC) have some limitation on data traffic bandwidth since a large number of silicon IPs share the bus. An on‐chip network is introduced to solve the problem of on‐chip buses, in which the concept of a computer network is applied to the communication architecture of SoC. We compared the performance of the MPEG‐4 video codec based on the on‐chip network and Advanced Micro‐controller Bus Architecture (AMBA) on‐chip bus. Experimental results show that the performance of the MPEG‐4 video codec based on the on‐chip network is improved over 50% compared to the design based on a multi‐layer AMBA bus.     

Performance modeling of MPEG‐4 video streaming over IEEE 802.11 using distribution coordination function

Delivering video streaming over wireless Internet is becoming increasingly popular. However, most of the research studies focused on the modeling analysis of system performance such as saturation throughput and channel utilization. Perceived quality of video streaming cannot be assessed solely based on the results of analytical models. In this paper, we propose a model to assess the perceived quality of MPEG‐4 video streaming over IEEE 802.11 distribution coordination function (DCF)‐based wireless local area networks. The analysis of our proposed model considers not only effects of losses such as collision loss from channel access competition but also wireless loss caused by wireless interferences. Moreover, the impact of the loss of specific MPEG‐4 video frames is also taken into account in the performance analysis. The model was validated by comparing our performance results with results obtained from simulation and analytical models. The results show that our proposed model is able to predict the perceived quality of MPEG‐4 video streaming over DCF‐based WLAN more accurately than other models. Copyright © 2010 John Wiley & Sons, Ltd.