Multimedia Broadcasting Applications Research Articles

Delivery of ATSC 3.0 Services With MPEG Media Transport Standard Considering Redistribution in MPEG-2 TS Format

MPEG-2 transport stream (TS), standardized by the ISO/IEC as part of the well-known MPEG-2 standards family, is the most widely deployed standard for multimedia services in traditional broadcast industry, such as ATSC and DVB-T. MPEG standards have been designed to specify essential features for multimedia broadcast applications, such as the structure of multimedia content composed of multiple audio-visual streams and temporal relationships among those streams. One of the new MPEG standards that was recently developed and published, namely MPEG media transport (MMT), has catered for the emerging convergence of digital broadcasting and the Internet. MMT inherits major advantageous features of MPEG-2 TS and adds advanced and innovative features to support broadcast services in the new converged environment. IP-based broadcast standards, e.g., ATSC 3.0, has gained significant attention by the broadcast industries as IP-based broadcast provides more flexible and enriched multimedia broadcast services to users. The ATSC 3.0 has adopted MMT as its one of media delivery technology to strengthen hybrid delivery of multimedia services which could be consumed on multiple devices simultaneously. This paper discusses the use of MMT in ATSC 3.0 service delivery. Important features of MMT will be described together with their restrictions and extensions that are needed to enable efficient delivery of ATSC 3.0 services.

Post-Processing for Blocking Artifact Reduction Based on Inter-Block Correlation

Block-based coding introduces an undesirable discontinuity between neighboring blocks in reconstructed images. This image degradation, referred to as blocking artifacts, arises mainly due to the loss of inter-block correlation in the quantization process of discrete cosine transform coefficients. In many multimedia broadcasting applications, such as a television, decoded video sequences suffer from blocking artifacts. In this paper, we present a novel post-processing algorithm based on increment of inter-block correlation aimed at reducing blocking artifacts. We first smooth the three lowest frequency discrete cosine transform (DCT) coefficients between neighboring blocks, in order to reduce blocking artifacts in the flat region, which are most sensitive to the human visual system. We then group each edge block and its matched blocks together and apply group-based filtering to increase the correlation between grouped blocks. This suppresses blocking artifacts in the edge region while preserving details. In addition, the algorithm is extended to reduce flickering artifacts as well as blocking artifacts in video sequences. Experimental results show that the proposed method successfully alleviates blocking artifacts in both images and videos coded with low bit-rates.

Unequal error protection for data partitioned H.264/AVC video broadcasting

Application Layer Forward Error Correction (AL-FEC) is becoming a popular addition to protocols for real-time video delivery over IP-based wireless networks. In particular, rateless codes are identified as suitable solution for AL-FEC due to their flexibility and capacity-approaching performance. Since each part of video data is not equally important for video reconstruction, it is beneficial to group it based on its importance, and then provide different degree of protection using Unequal Error Protection (UEP). Data partitioning (DP) is one such low-cost feature in H.264/AVC enabling partitioning of video data based on its importance. We propose schemes for the DP H.264/AVC video transmission using Raptor and Random Linear Codes (RLC) and investigate their performance as AL-FEC solutions in Digital Video Broadcasting. We provide comparisons between optimized Non-Overlapping Window RLC and Expanding Window (EW) RLC, which are two effective UEP RLC strategies. The results using realistic channel traces show viability of the EW RLC as a promising solution for multimedia broadcast applications.

Application Layer Systematic Network Coding for Sliced H.264/AVC Video Streaming

Application Layer Forward Error Correction (AL-FEC) with rateless codes can be applied to protect the video data over lossy channels. Expanding Window Random Linear Codes (EW RLCs) are a flexible unequal error protection fountain coding scheme which can provide prioritized data transmission. In this paper, we propose a system that exploits systematic EW RLC for H.264/Advanced Video Coding (AVC) slice-partitioned data. The system prioritizes slices based on their PSNR contribution to reconstruction as well as temporal significance. Simulation results demonstrate usefulness of using relative slice priority with systematic codes for multimedia broadcast applications.

Revisiting relative neighborhood graph-based broadcasting algorithms for multimedia ad hoc wireless networks

Multimedia broadcasting is a popular application in an ad hoc wireless network, itself composed of battery-operated nodes. Hence, energy conservation and avoidance of frequent re-construction of broadcast paths are crucial to ensure robust and uninterrupted service of multimedia broadcasting applications. This paper introduces a class of distributed broadcast algorithms based on variations of Relative Neighborhood Graphs (RNG). In contrast to the original RNG-based algorithms, the proposed algorithms consider the remaining battery energy of nodes and the distance between nodes as criteria for determining the relative neighborhood of a node. This approach is intended to boost the resiliency of the broadcast path by avoiding the choice of nodes with low remaining battery capacity as rebroadcast nodes. Extensive simulations are conducted, demonstrating that the proposed algorithms improve over the original RNG in several aspects, including the reduction of broadcast storms, longer path lifetime, and shorter broadcast latency.

Efficient Multi-Reference Frame Selection Algorithm for Hierarchical B Pictures in Multiview Video Coding

Multiple reference frame prediction technology is adopted in Multiview Video Coding (MVC) to explore temporal and inter-view redundancies of multiview videos, resulting in extremely high encoding complexity by searching the best reference frame indices and the best reference directions for each macroblock (MB). In order to reduce MVC coding computations while keeping the coding efficiency and thus to advance MVC in real-time multimedia broadcasting applications, we propose a Fast Multi-reference Frame Selection Algorithm (FMFSA) for hierarchical B picture prediction structure in this paper. Due to high spatial correlations within a MB, there is a high probability for smaller MB partition modes selecting the same reference frame and direction as B16 16 does. Therefore, the reference information of latter checked MB partition modes can be directly set according to the reference information of previous examined mode. Experimental results on MVC show that the proposed FMFSA can achieve 68.34%~79.01% total encoding time reduction while the average bit rate increase and peak signal-to-noise ratio degradation are within 0.54% and 0.04 dB, respectively for test multiview sequences with various motion properties and camera arrangements.

Efficient multiplexing scheme for IP packets over the advanced satellite broadcasting system

Implementing an IP-friendly transport mechanism in broadcasting systems would enable more convenient multimedia broadcasting applications. The overhead of current multiplexing methods for IP packets that are based on MPEG-2 systems is large, and they are not well suited for efficient transmission of IP packets. We developed an efficient scheme for transporting IP packets over broadcasting channels. The scheme includes compression of IP header information, transmission control signals for listing IP multicast group addresses, and a simple encapsulation. This paper describes the multiplexing scheme and its theoretical overhead. We conducted an experiment on a prototype transmission system that shows our scheme is efficiency.

Two-Way Digital Video Transmission over Medium-Voltage Power-Lines Using Time-Domain Synchronous Orthogonal Frequency Division Multiplexing Technology

This paper describes field trials of two-way digital video transmissions over a 700-m long medium-voltage power cable using a frequency division duplex scheme. The purpose is to check the feasibility of using time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) technology in powerline communication (PLC). TDS-OFDM is the core technology in digital multimedia broadcasting-terrestrial (DMB-T), developed by Tsinghua University for digital television terrestrial multimedia broadcast applications and successfully adopted in the Chinese Digital Terrestrial Television Broadcasting Standard. PLC systems are widely believed to be bandwidth or data throughput limited. However, the use of known pseudo random sequences as guard intervals for synchronization and channel estimation in TDS-OFDM greatly reduces the system overhead and increases the spectrum efficiency. These experiments show that TDS-OFDM is appropriate not only for broadcasting but also for PLC applications with appropriate modifications.

Potential Frequency Bands for Terrestrial Mobile Multimedia Broadcasting Applications

While terrestrial mobile multimedia broadcasting presents an exciting opportunity for both innovation and convergence to provide multimedia services in new operating environments, it remains a challenge to locate frequency spectrum in which to deploy these applications. The fact is that the frequencies suitable for such applications in a mobile environment are already heavily encumbered, and it is difficult to locate bands that are harmonized, even on a regional basis. Nonetheless, there are also opportunities for new mobile multimedia broadcasting applications, given the transition to technologies that more efficiently utilize spectrum, such as in the case of the analog to digital television transition