Scalable Video Services Research Articles

Bitrate Estimation for Spatial Scalable Videos

Spatial scalable video service has surged in the time of multiple screens. Existing bitrate allocation methods are principled by rate-distortion theory and characterized by iterative encoding, which is accurate yet complex. However, the quasi-quantitative description is preferred in practice of broadcasting. In this paper, we propose a task of bitrate estimation for scalable videos concerning the content, aiming at a more efficient model at the cost of precision. First, we exhibit necessity to build a model for Scalable High Efficiency Video Coding (SHVC) and quantitative relation between video content and bitrate using different encoders. Then, a scalable-video dataset is prepared. It covers various types of content to offer diversity for model training. In the end, multi-linear regression is utilized to estimate the bitrate of scalable videos, with spatial and temporal indices as explanatory variables. Our statistical experiments show the model is able to estimate bitrate after trained on the self-built dataset.

Network Coding Aided Collaborative Real-Time Scalable Video Transmission in D2D Communications

There has been an increasing demand for providing real-time video streaming services in the next-generation cellular networks. To improve the quality of such services without additional infrastructure, neighboring devices can recover missing packets by using network coding aided collaborative transmission via device-to-device (D2D) communication. However, most existing work in this area had not considered the issue of how to schedule such coding aided collaborative transmissions effectively for supporting real - time scalable video applications in such environment. In this paper, we study how to improve the quality of real-time scalable video services by efficiently scheduling coding aided collaborative transmissions. We first formulate the problem of optimal collaborative transmission scheduling that determines the optimal transmitting sequence and coding pattern at each transmitting device, which is shown to be NP-hard. To address this problem, we propose a new weight function for measuring the quality of a coding pattern by considering packet recovery gain and potential video decoding gain at receivers. Based on this new weight function, we propose a low complexity centralized algorithm using global state information and an efficient distributed mechanism supporting localized operations in dynamic environment. We deduce their computational complexities. Simulation results verify that the proposed solution outperforms the representative work in the literature.

Adaptive Layer Switching Algorithm Based on Buffer Underflow Probability for Scalable Video Streaming Over Wireless Networks

Scalable Video Coding (SVC) has been raised as a promising technique to enable flexible video transmission for mobile users with heterogeneous terminals and varying channel capacities. In this paper, we design an adaptive layer switching algorithm for on-demand scalable video service based on receiver’s buffer underflow probability (BUP). Since the low quality of channel may lead to a low buffer fullness, the buffer fullness is an indicator for reflecting the channel condition and we define BUP for characterizing the mismatch between the video bitrate and the channel throughput. Accordingly, the adaptive SVC transmission problem is formulated as the adaptive adjustment of video layers based on BUP. This allows us to optimize the attainable video quality, while keeping BUP below a desired level. To estimate BUP, we derive an analytical model based on the large deviation principles. Then, an online layer switching algorithm is proposed using this estimation model, which is capable of accommodating different channel qualities without any prior knowledge of the channel variations and of the video characteristics. We further introduce a perturbation-based layer switching approach for reducing the quality fluctuating issue caused by frequent layer switches, thus improving the viewer’s quality of experience. A system prototype is implemented to evaluate the success of the proposed method. We also conduct simulations in multiuser scenarios with real video traces and the results demonstrate that the proposed algorithm is capable of improving the playback experience, while keeping a low playback interruption rate and quality variation.

Design and Evaluation of Novel Scalability Techniques for Adaptation over Heterogeneous Networks

This paper addresses the issues concerned with the provision of scalable video services over heterogeneous networks particularly with regards to dynamic adaptation and user's acceptable quality of service. In order to provide and sustain an adaptive and network friendly multimedia communication service, a suite of techniques that achieved automatic scalability and adaptation are developed using H.264/AVC Extension codec platform. The objective, subjective and real time performances of the techniques are evaluated to assess the Quality of Service (QoS) provided to diverse users with variable constraints and dynamic resources. The techniques are further evaluated with view to establish their performance against state of the art scalable and none-scalable techniques. Several experiments and simulations revealed that the proposed techniques outperformed state-of-the-art and none-scalable(SL) techniques. The designed techniques provide an automated scalability adaptation on the video stream and showed up to 50% gain in scalability adaptation against single layer (SL) and none-combined scalability techniques. Keywords: Adaptation, Dynamic-Scalability, H.264/AVC, Heterogeneous-Networks, Scalability.

Energy Saving Multicast Mechanism for Scalable Video Service Using Opportunistic Scheduling

In this paper, we focus on energy-efficient opportunistic multicast scheduling design method and user sleeping mechanism for the scalable video transmission in a wireless network. The goal is to minimize the total energy consumption for the terminal when receiving streaming video with bandwidth constraint and users' minimum QoS requirements. To utilize opportunistic multicast scheduling, unequal erasure protection (UXP) scheme is used for scalable video at the application layer. Considering the encoding characteristics and unequal protection scheme of scalable video, the UXP frame-level QoS is defined. And a low-complexity scheduling algorithm is proposed by transforming frame-level QoS requirement into slot-level QoS requirement within each time slot dynamically. Performance evaluations are firstly conducted for general data service with unlimited number of transmission rates, and then extended to scalable video service with limited number of transmission rates. Simulation results show that our proposed algorithm has less energy consumption of all the multicast users than the conventional scheduling schemes with the same users' QoS requirements guaranteed in both homogeneous and heterogeneous networks.

Radio Resource Allocation for Scalable Video Services Over Wireless Cellular Networks

Good quality video services always require higher bandwidth. Hence, to provide the video services e.g., multicast/broadcast services (MBSs) and unicast services along with the existing voice, internet, and other background traffic services over the wireless cellular networks, it is required to efficiently manage the wireless resources in order to reduce the overall forced call termination probability, to maximize the overall service quality, and to maximize the revenue. Fixed bandwidth allocation for the MBS sessions either reduces the quality of the MBS videos and bandwidth utilization or increases the overall forced call termination probability and of course the handover call dropping probability as well. Scalable video coding (SVC) technique allows the variable bit rate allocation for the video services. In this paper, we propose a bandwidth allocation scheme that efficiently allocates bandwidth among the MBS sessions and the non-MBS traffic calls (e.g., voice, unicast, internet, and other background traffic). The proposed scheme reduces the bandwidth allocation for the MBS sessions during the congested traffic condition only to accommodate more calls in the system. Instead of allocating fixed bandwidths for the MBS sessions and the non-MBS traffic, our scheme allocates variable bandwidths for them. However, the minimum quality of the videos is guaranteed by allocating minimum bandwidth for them. Using the mathematical and numerical analyses, we show that the proposed scheme maximizes the bandwidth utilization and significantly reduces the overall forced call termination probability as well as the handover call dropping probability.

Data reorganization for scalable video service with embedded mobile devices

Recent development of high-speed wireless networks and embedded systems has enabled the recording and delivery of high-performance multimedia to heterogeneous mobile users. To support heterogeneous mobile users with high-quality multimedia services, scalable video coding was introduced. In the scalable video coding (SVC), through multidimensional scalability, all types of these scalability can be exploited at the same time. However, the generated video sequences of scalable video coding are not adequate for mobile multimedia service systems since its flexibility makes non contiguous storing and retrieval of partial stream data. In this article, we propose efficient scalable video data reorganization for video servicing systems, which consist of video server and mobile clients. For video server, we reorganize scalable video streams taking into account both of decoding dependency and location in disk array storage, where disk array is widely used for storage systems of video server. In the mobile devices, we place substreams with the consideration of NAND flash memory page and block boundaries, which is storage for mobile devices. The experimental results show that the proposed reorganization of scalable video can improve the performance of mobile multimedia service systems.

Cross-Layer Quality Assessment of Scalable Video Services on Mobile Embedded Systems

The recent development of high-speed data transmission over wireless cellular networks has enabled the delivery of multimedia broadcasting services to mobile users. These services involve a range of interactions among different system components, including the wireless channel, the network, and mobile devices, making it crucial for the service provider to verify the model, design, and behavior of a new service before it is deployed. However, previous studies have largely relied on network simulations or scaled experiments, and there has been little work on the sort of unified framework for quality-of-service (QoS) assessment, which considers the interactions between components, that we propose in this paper. Accurate models of the wireless channel, the network, and the data processing that takes place on an embedded system of a mobile client, are integrated within our framework, and allow us to predict several key system metrics and the quality of the video stream as it is perceived by users. Furthermore, different models of system components can be easily plugged in to extend this framework. As an example application, we analyze the performance of the process of decoding scalable videos on ARM-based mobile embedded systems in CDMA2000 wireless cellular networks.

Caching collaboration and cache allocation in peer-to-peer video systems

Providing scalable video services in a peer-to-peer (P2P) environment is challenging. Since videos are typically large and require high communication bandwidth for delivery, many peers may be unwilling to cache them in whole to serve others. In this paper, we address two fundamental research problems in providing scalable P2P video services: (1) how a host can find enough video pieces, which may scatter among the whole system, to assemble a complete video; and (2) given a limited buffer size, what part of a video a host should cache and what existing data should be expunged to make necessary space. We address these problems with two new ideas: Cell caching collaboration and Controlled Inverse Proportional (CIP) cache allocation. The Cell concept allows cost-effective caching collaboration in a fully distributed environment and can dramatically reduce video lookup cost. On the other hand, CIP cache allocation challenges the conventional caching wisdom by caching unpopular videos in higher priority. Our approach allows the system to retain many copies of popular videos to avoid creating hot spots and at the same time, prevent unpopular videos from being quickly evicted from the system. We have implemented a Gnutella-like simulation network and use it as a testbed to evaluate the proposed technique. Our extensive study shows convincingly the performance advantage of the new scheme.

Quality control for VBR video over ATM networks

Uncontrolled variable-bit-rate (VBR) coded video yields consistent picture quality, but the traffic stream is very bursty. When sent over ATM networks, cell losses may be incurred due to limited buffer capacity at the switches; this could cause severe picture quality degradation. Source rate control can be implemented to generate a controlled VBR bit stream which conforms to specified bit rate bounds and buffer constraints. However, source rate control could result in picture quality degradation too. Hence, for real-time video services, an important issue to address is whether the picture quality degradation incurred by source rate control is within acceptable levels or how to choose the appropriate coding parameters to make it so. We establish quantitatively the relationship between picture quality and source rate control for the case of guaranteed service with different combinations of allocated bandwidth, buffer size, and other key video-coding parameters of MPEG-2. In addition, quality control in the context of two-layered scalable video service (basic and enhanced quality) is also considered. Our study reveals that, in order to maximize both the basic and the enhanced quality, source rate control should be implemented on both layers. The relationships between the two types of quality and different combinations of allocated bandwidths, buffer sizes, and some key coding parameters are also established quantitatively for MPEG-2 SNR scalability.