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45
Video transport evaluation with H.264 video traces
- Fourth Quarter
, 2012
"... Abstract—The performance evaluation of video transport mechanisms becomes increasingly important as encoded video accounts for growing portions of the network traffic. Compared to the widely studied MPEG-4 encoded video, the recently adopted H.264 video coding standards include novel mechanisms, suc ..."
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Abstract—The performance evaluation of video transport mechanisms becomes increasingly important as encoded video accounts for growing portions of the network traffic. Compared to the widely studied MPEG-4 encoded video, the recently adopted H.264 video coding standards include novel mechanisms, such as hierarchical B frame prediction structures and highly efficient quality scalable coding, that have important implications for network transport. This tutorial introduces a trace-based evaluation methodology for the network transport of H.264 encoded video. We first give an overview of H.264 video coding, and then present the trace structures for capturing the characteristics of H.264 encoded video. We give an overview of the typical video traffic and quality characteristics of H.264 encoded video. Finally, we explain how to account for the H.264 specific coding mechanisms, such as hierarchical B frames, in networking studies. Index Terms—H.264 encoded video, hierarchical B frames, medium grain scalability (MGS), network transport, simulation, traffic variability, video trace.
Seamless wireless connectivity for multimedia services in high speed trains
- IEEE J. Sel. Areas Commun
, 2012
"... Abstract—The recent advent of high speed trains introduces new mobility patterns in wireless environments. The LTE-A (Long Term Evolution of 3GPP- Advanced) networks have largely tackled the Doppler effect problem in the physical layer and are able to keep wireless service with 100Mpbs throughput wi ..."
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Cited by 10 (1 self)
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Abstract—The recent advent of high speed trains introduces new mobility patterns in wireless environments. The LTE-A (Long Term Evolution of 3GPP- Advanced) networks have largely tackled the Doppler effect problem in the physical layer and are able to keep wireless service with 100Mpbs throughput within a cell in speeds up to 350 km/h. Yet the much more frequent handovers across cells greatly increases the possibility of service interruptions, and the problem is prominent for multimedia communications that demand both high-throughput and continuous connections. In this paper, we present a novel LTE-based solution to support high throughput and continuous multimedia services for high speed train passengers. Our solution is based on a Cell Array that smartly organizes the cells along a railway, together with a femto cell service that aggregates trafc demands within individual train cabins. Given that the movement direction and speed of a high-speed train are generally known, our Cell Array effectively predicts the upcoming LTE cells in service, and enables a seamless handover that will not interrupt multimedia streams. To accommodate the extreme channel variations, we further propose a scheduling and resource allocation mechanism to maximize the service rate based on periodical signal quality changes. Our simulation under diverse network and railway/train congurations demonstrates that the proposed solution achieves much lower handover latency and higher data throughput, as compared to existing solutions. It also well resists to network and trafc dynamics, thus enabling uninterrupted quality multimedia services for passengers in high speed trains.
Traffic and Quality Characterization of the H.264/AVC Scalable Video Coding Extension
, 2008
"... The recent scalable video coding (SVC) extension to the H.264/AVC video coding standard has unprecedented compression efficiency while supporting a wide range of scalability modes, including temporal, spatial, and quality (SNR) scalability, as well as combined spatiotemporal SNR scalability. The tra ..."
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Cited by 10 (3 self)
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The recent scalable video coding (SVC) extension to the H.264/AVC video coding standard has unprecedented compression efficiency while supporting a wide range of scalability modes, including temporal, spatial, and quality (SNR) scalability, as well as combined spatiotemporal SNR scalability. The traffic characteristics, especially the bit rate variabilities, of the individual layer streams critically affect their network transport. We study the SVC traffic statistics, including the bit rate distortion and bit rate variability distortion, with long CIF resolution video sequences and compare them with the corresponding MPEG-4 Part 2 traffic statistics. We consider (i) temporal scalability with three temporal layers, (ii) spatial scalability with a QCIF base layer and a CIF enhancement layer, as well as (iii) quality scalability modes FGS and MGS. We find that the significant improvement in RD efficiency of SVC is accompanied by substantially higher traffic variabilities as compared to the equivalent MPEG-4 Part 2 streams. We find that separately analyzing the traffic of temporal-scalability only encodings gives reasonable estimates of the traffic statistics of the temporal layers embedded in combined spatiotemporal encodings and in the base layer of combined FGS-temporal encodings. Overall, we find that SVC achieves significantly higher compression ratios than MPEG-4 Part 2, but produces unprecedented levels of traffic variability, thus presenting new challenges for the network transport of scalable video.
RESEARCH Video coding with dynamic background
"... Motion estimation (ME) and motion compensation (MC) using variable block size, sub-pixel search, and multiple reference frames (MRFs) are the major reasons for improved coding performance of the H.264 video coding standard over other contemporary coding standards. The concept of MRFs is suitable for ..."
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Cited by 6 (3 self)
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Motion estimation (ME) and motion compensation (MC) using variable block size, sub-pixel search, and multiple reference frames (MRFs) are the major reasons for improved coding performance of the H.264 video coding standard over other contemporary coding standards. The concept of MRFs is suitable for repetitive motion, uncovered background, non-integer pixel displacement, lighting change, etc. The requirement of index codes of the reference frames, computational time in ME & MC, and memory buffer for coded frames limits the number of reference frames used in practical applications. In typical video sequences, the previous frame is used as a reference frame with 68–92 % of cases. In this article, we propose a new video coding method using a reference frame [i.e., the most common frame in scene (McFIS)] generated by dynamic background modeling. McFIS is more effective in terms of rate-distortion and computational time performance compared to the MRFs techniques. It has also inherent capability of scene change detection (SCD) for adaptive group of picture (GOP) size determination. As a result, we integrate SCD (for GOP determination) with reference frame generation. The experimental results show that the proposed coding scheme outperforms the H.264 video coding with five reference frames and the two relevant state-of-the-art algorithms by 0.5–2.0 dB with less computational time.
VMP: a MAC protocol for EPON-based video-dominated FiWi access networks
- IEEE Transactions on Broadcasting
, 2012
"... Abstract—Optical and wireless network technologies are ex-pected to converge in the near to midterm, giving rise to bimodal fiber-wireless (FiWi) broadband access networks. In triple-play (voice, video, and data) service scenarios for such FiWi access networks, video traffic will likely dominate due ..."
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Cited by 6 (4 self)
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Abstract—Optical and wireless network technologies are ex-pected to converge in the near to midterm, giving rise to bimodal fiber-wireless (FiWi) broadband access networks. In triple-play (voice, video, and data) service scenarios for such FiWi access networks, video traffic will likely dominate due to the widely predicted increase in video network services and the high traffic volume of compressed video compared to voice and data services. In this paper, we introduce and evaluate a comprehensive video MAC protocol (VMP) to efficiently deliver prerecorded video downstream to wireless consumers over a FiWi network in the presence of voice and data upstream and downstream traffic. VMP consists of three main novel components: (i) frame fragmentation in conjunction with hierarchical frame aggregation for efficient MAC frame transport over the integrated optical and wireless network segments, (ii) multi-polling medium access control for upstream voice and data packets and acknowledgements for downstream video packets, and (iii) prefetching of video frames over the optical and wireless network segments in conjunction with hybrid reservation/contention-based medium access. Our simula-tion results indicate that VMP achieves significant improvements in throughput-delay performance for all three traffic types as well as reductions in the playback starvation probability for video traffic compared to existing state-of-the-art MAC mechanisms.
1 Traffic and Statistical Multiplexing Characterization of 3D Video Representation Formats (Extended Version)
"... Abstract—The network transport of 3D video, which contains two views of a video scene, poses significant challenges due to the increased video data compared to conventional single-view video. Addressing these challenges requires a thorough understanding of the traffic and multiplexing characteristic ..."
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Cited by 5 (2 self)
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Abstract—The network transport of 3D video, which contains two views of a video scene, poses significant challenges due to the increased video data compared to conventional single-view video. Addressing these challenges requires a thorough understanding of the traffic and multiplexing characteristics of the different representation formats of 3D video. We examine the average bitrate-distortion (RD) and bitrate variability-distortion (VD) characteristics of three main representation formats. Specifically, we compare multiview video (MV) representation and encoding, frame sequential (FS) representation, and side-by-side (SBS) representation, whereby conventional single-view encoding is employed for the FS and SBS representations. Our results for long 3D videos in full HD format indicate that the MV representation and encoding achieves the highest RD efficiency, while exhibiting the highest bitrate variabilities. We examine the impact of these bitrate variabilities on network transport through extensive statistical multiplexing simulations. We find that when multiplexing a small number of streams, the MV and FS representations require the same bandwidth. However, when multiplexing a large number of streams or smoothing traffic, the MV representation and encoding reduces the bandwidth requirement relative to the FS representation. I.
MORPHOSYS: Efficient Colocation of QoS-Constrained Workloads
- Boston University
, 2011
"... Abstract—In hosting environments such as IaaS clouds, desirable application performance is usually guaranteed through the use of Service Level Agreements (SLAs), which specify minimal fractions of resource capacities that must be allocated for unencumbered use for proper operation. Arbitrary colocat ..."
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Cited by 4 (2 self)
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Abstract—In hosting environments such as IaaS clouds, desirable application performance is usually guaranteed through the use of Service Level Agreements (SLAs), which specify minimal fractions of resource capacities that must be allocated for unencumbered use for proper operation. Arbitrary colocation of applications with different SLAs on a single host may result in inefficient utilization of the host’s resources. In this paper, we propose that periodic resource allocation and consumption models – often used to characterize real-time workloads – be used for a more granular expression of SLAs. Our proposed SLA model has the salient feature that it exposes flexibilities that enable the infrastructure provider to safely transform SLAs from one form to another for the purpose of achieving more efficient colocation. Towards that goal, we present MORPHOSYS: a framework for a service that allows the manipulation of SLAs to enable efficient colocation of arbitrary workloads in a dynamic setting. We present results from extensive trace-driven simulations of colocated Video-on-Demand servers in a cloud setting. These results show that potentially-significant reduction in wasted resources (by as much as 60%) are possible using MORPHOSYS. I.
H.264/AVC and SVC Video Trace Library: A Quick Reference Guide
, 2009
"... There are three ways to characterize encoded video for the purpose of networking research: (i) video traffic model, (ii) video bit stream, and (iii) video traffic trace. Video traffic models strive to capture the essential properties of the real traffic in parsimonious mathematical models. Video tra ..."
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Cited by 3 (0 self)
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There are three ways to characterize encoded video for the purpose of networking research: (i) video traffic model, (ii) video bit stream, and (iii) video traffic trace. Video traffic models strive to capture the essential properties of the real traffic in parsimonious mathematical models. Video traffic models are typically developed based on the statistical properties of samples of the real traffic, or, in many cases, video traces of the real traffic. Video traces are therefore typically a prerequisite for model development. Video traffic models for H.264/AVC and H.264 SVC are largely an open research area. The bit stream contains the complete video information and allows for networking experiments where the quality of the video—after suffering losses in the network—is evaluated (a capability that can be emulated with offset distortion video traces [6]. Key limitations of the bit streams are that they require expertise in video coding, are very large in size, and are usually proprietary and/or protected by copyright. Video traces are an attractive alternative to traffic models and bit streams in that they represent the traffic and quality of the videos. While the bit streams contain the actual bits carrying the video information, the traces are simple files that contain the number of bits needed to encode each video frame and the quality level (e.g., in PSNR) of the encoding [7]. Thus, there are no copyright
The Effects of Priority Levels and Buffering on the Statistical Multiplexing of Single-Layer H.264/AVC and SVC Encoded Video Streams
"... Abstract—H.264/Advanced Video Coding (AVC) employs classical bi-directional encoded (B) frames that depend only on intracoded (I) and predictive encoded (P) frames. In contrast, H.264 Scalable Video Coding (SVC) employs hierarchical B frames that depend on other B frames. A fundamental question is h ..."
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Cited by 3 (1 self)
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Abstract—H.264/Advanced Video Coding (AVC) employs classical bi-directional encoded (B) frames that depend only on intracoded (I) and predictive encoded (P) frames. In contrast, H.264 Scalable Video Coding (SVC) employs hierarchical B frames that depend on other B frames. A fundamental question is how many priority levels single-layer H.264 video encodings require when the encoded frames are statistically multiplexed in transport networks. We conduct extensive simulation experiments with a modular statistical multiplexing structure to uncover the impact of priority levels for a wide range of multiplexing policies. For the bufferless statistical multiplexing of both H.264/AVC and SVC we find that prioritizing the frames according to the number of dependent frames can increase the number of supported streams up to approximately 8%. In contrast, for buffered statistical multiplexing with a relatively small buffer size, frame prioritization does generally not increase the number of supported streams. Index Terms—Frame dependencies, H.264/AVC, H.264 SVC, multiplexing policy, statistical multiplexing.
Implications of Smoothing on Statistical Multiplexing of H.264/AVC and SVC Video Streams
"... Abstract—While the hierarchical B frames based Scalable Video Coding (SVC) extension of the H.264/AVC standard achieves sig-nificantly improved compression over the initial H.264/AVC codec, the SVC video traffic is significantly more variable than H.264/AVC traffic. The higher traffic variability of ..."
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Cited by 3 (3 self)
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Abstract—While the hierarchical B frames based Scalable Video Coding (SVC) extension of the H.264/AVC standard achieves sig-nificantly improved compression over the initial H.264/AVC codec, the SVC video traffic is significantly more variable than H.264/AVC traffic. The higher traffic variability of the SVC encoder can lead to smaller numbers of streams supported with bufferless statistical multiplexing than with the H.264/AVC encoder (and even less streams than with the MPEG-4 Part 2 encoder) for prescribed link capacities and loss constraints. In this paper we examine the implications of video traffic smoothing on the numbers of statistically multiplexed H.264 SVC, H.264/AVC, and MPEG-4 Part 2 streams, the bandwidth requirements for streaming, and the introduced delay. We identify the levels of smoothing that ensure that more H.264 SVC streams than H.264/AVC streams can be supported. For a basic low-complexity smoothing technique that is readily applicable to both live and prerecorded streams, we identify the levels of smoothing that give (bufferless) statistical multiplexing performance close to an optimal off-line smoothing technique. We thus characterize the trade-offs between increased smoothing delay and increased statistical multiplexing performance for both H.264/AVC, which employs classical B frames, and H.264 SVC, which employs hier-archical B frames. We similarly identify the buffer sizes for the buffered multiplexing of unsmoothed H.264 SVC, H.264/AVC, and MPEG-4 Part 2 streams that give close to optimal performance. Index Terms—Delay, H.264/AVC, hierarchical B frames, smoothing, statistical multiplexing, SVC, video traffic. I.
