The split and merge (SAM) protocol for interactive video-on-demand systems

A true video-on-demand (VOD) system provides the ultimate flexibility in video services by allowing users to select any video programs, at any time, and to perform any VCR-like user interactions. To allow true VOD, one approach is to have a dedicated video stream for each customer. This is expensive, especially when multiple identical video streams are sent to multiple customers accessing the same video. To be commercially viable, VOD service must be priced competitively with existing video rental services. Batching may be used to reduce this cost. It allows multiple users accessing the same video to share the same video stream. The batching approach, however, complicates the provision of user interactions. Existing batching schemes only allow near VOD services. This paper describes a new protocol, called split and merge (SAM), which offers true VOD services while allowing multiple users to share the same video stream. This sharing is transparent to the users and it appears as if each has a dedicated video stream. Our approach is to split an interactive user from the batch and to serve him with a dedicated video stream. We develop an innovative way to merge these individuals back to the batching streams when they resume normal play mode. The SAM protocol therefore significantly improves the system resource utilization and the number of simultaneous users, and more importantly, allows true VOD services.published_or_final_versio

A Scalable Solution For Interactive Video Streaming

This dissertation presents an overall solution for interactive Near Video On Demand (NVOD) systems, where limited server and network resources prevent the system from servicing all customers’ requests. The interactive nature of recent workloads complicates matters further. Interactive requests require additional resources to be handled. This dissertation analyzes the system performance under a realistic workload using different stream merging techniques and scheduling policies. It considers a wide range of system parameters and studies their impact on the waiting and blocking metrics. In order to improve waiting customers experience, we propose a new scheduling policy for waiting customers that is fairer and delivers a descent performance. Blocking is a major issue in interactive NVOD systems and we propose a few techniques to minimize it. In particular, we study the maximum Interactive Stream (I-Stream) length (Threshold) that should be allowed in order to prevent a few requests from using the expensive I-Streams for a prolonged period of time, which starves other requests from a chance of using this valuable resource. Using a reasonable I-Stream threshold proves very effective in improving blocking metrics. Moreover, we introduce an I-Stream provisioning policy to dynamically shift resources based on the system requirements at the time. The proposed policy proves to be highly effective in improving the overall system performance. To account for both average waiting time and average blocking time, we introduce a new metric (Aggregate Delay) . We study the client-side cache management policy. We utilize the customer’s cache to service most interactive requests, which reduces the load on the server. We propose three purging algorithms to clear data when the cache gets full. Purge Oldest removes the oldest data in the cache, whereas Purge Furthest clears the furthest data from the client’s playback point. In contrast, Adaptive Purge tries to avoid purging any data that includes the customer’s playback point or the playback point of any stream that is being listened to by the client. Additionally, we study the impact of the purge block, which is the least amount of data to be cleared, on the system performance. Finally, we study the effect of bookmarking on the system performance. A video segment that is searched and watched repeatedly is called a hotspot and is pointed to by a bookmark. We introduce three enhancements to effectively support bookmarking. Specifically, we propose a new purging algorithm to avoid purging hotspot data if it is already cached. On top of that, we fetch hotspot data for customers not listening to any stream. Furthermore, we reserve multicast channels to fetch hotspot data

Personal information service (PIS)-an application of wide-band communications, 2012 A.D.

With the affluence that comes with economic developments and technological advances, citizens around the world will require personalized, on-demand, high-quality information services, which the author calls personal information service (PIS). He foresees that by 2012 A.D., a variety of communication services, and in particular PIS, will be much more widely available around the world. To make such services available to the masses, a number of challenges have to be overcome. In this paper, the author addresses the challenges. He believes that by working together solutions can be obtained by 2012 A.D.published_or_final_versio

Network architecture in a large-scale fully interactive VOD system based on hybrid multicast-unicast streaming.

Chan Kwun-chung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.Includes bibliographical references (leaves 71-73).Abstracts in English and Chinese.摘要 --- p.IIABSTRACT --- p.IIIACKNOWLEDGEMENT --- p.VTABLE OF CONTENTS --- p.VILIST OF FIGURES --- p.XLIST OF SYMBOLS --- p.XIIChapter 1. --- INTRODUCTION --- p.1Chapter 1.1 --- Contributions --- p.3Chapter 1.2 --- Organization of the Thesis --- p.4Chapter 1.3 --- Publications --- p.5Chapter 2. --- RELATED WORKS --- p.6Chapter 2.1 --- Previous VOD System --- p.7Chapter 2.1.1 --- Service Model --- p.7Chapter 2.1.1.1 --- Unicast VOD --- p.7Chapter 2.1.1.2 --- Multicast VOD --- p.8Chapter 2.1.2 --- Architecture --- p.9Chapter 2.1.2.1 --- Centralized Architecture --- p.9Chapter 2.1.2.2 --- Distributed Architecture --- p.10Chapter 2.1.3 --- Interactive Function --- p.11Chapter 2.1.3.1 --- Limited Interactive Function --- p.11Chapter 2.1.3.2 --- Unlimited Interactive Function --- p.11Chapter 2.1.4 --- Split and Merge Operation --- p.12Chapter 2.1.4.1 --- SAM Scheme (Split and Merge) --- p.12Chapter 2.1.4.2 --- SRMDRU Scheme (Single Rate Multicast Double Rate Unicast) --- p.14Chapter 2.2 --- Previous Caching Algorithm --- p.15Chapter 2.2.1 --- LFU (Least Frequently Used) --- p.15Chapter 2.2.2 --- LRU (Least Recently Used) --- p.15Chapter 2.2.3 --- Media Stream Caching --- p.15Chapter 3. --- DESIGN OFA NOVEL VOD SYSTEM --- p.17Chapter 3.1 --- System Architecture --- p.18Chapter 3.1.1 --- Multicast Video Server Cluster (MVSC) --- p.19Chapter 3.1.2 --- Unicast Video Server Cluster (UVSC) --- p.20Chapter 3.1.3 --- Multicast Backbone Network (MBN) --- p.20Chapter 3.1.4 --- Local Distribution Network (LDN) --- p.21Chapter 3.1.5 --- Distributed Interactive Server (DIS) --- p.21Chapter 3.1.6 --- Distributed Proxy Server (DPS) --- p.22Chapter 3.1.7 --- Client Station (CS) --- p.22Chapter 3.2 --- Batched Multicast Transmission --- p.24Chapter 3.3 --- Split and Merge Operation --- p.26Chapter 3.4 --- Interactive Function --- p.31Chapter 3.4.1 --- Pause --- p.31Chapter 3.4.2 --- Slow Motion --- p.35Chapter 3.4.3 --- Various Speed Fast Forward / Fast Rewind (FF/REW) --- p.37Chapter 3.4.4 --- Jump Forward/Jump Backward (JF/JB) --- p.42Chapter 3.5 --- Performance Analysis --- p.46Chapter 3.5.1 --- Model --- p.46Chapter 3.5.2 --- System Parameters --- p.49Chapter 3.5.3 --- Results --- p.49Chapter 4. --- DESIGN OF A VIDEO PROXY SYSTEM --- p.57Chapter 4.1 --- Video Proxy System --- p.58Chapter 4.1.1 --- Priority Function --- p.59Chapter 4.1.2 --- Two-Stage Replacement Policy --- p.60Chapter 4.1.3 --- Caching Policy --- p.61Chapter 4.2 --- Performance Evaluation --- p.63Chapter 4.2.1 --- Simulation Environment --- p.63Chapter 4.2.2 --- Performance Metric --- p.64Chapter 4.2.3 --- Results --- p.64Chapter 5. --- CONCLUSION --- p.69BIBLIOGRAPHY --- p.7

Best-Effort Patching for Multicast True VoD Service

A multicast Video-on-Demand (VoD) system allows clients to share a server stream by batching their requests, and hence, improves channel utilization. However, it is very difficult to equip such a VoD system with full support for interactive VCR functions which are important to a growing number of Internet applications. In order to eliminate service (admission) latency, patching was proposed to enable an existing multicast session to dynamically add new clients, and requests can be served without delay if patching channels are available. A true VoD (TVoD) service should support not only zero-delay client admission but also continuous VCR-like interactivity. However, the conventional patching is only suitable for admission control. We propose a new patching scheme, called Best-Effort Patching (BEP), that offers a TVoD service in terms of both request admission and VCR interactivity. Moreover, by using a novel dynamic merging algorithm, BEP significantly improves the efficiency of TVoD interactivity, especially for popular videos. We also model and evaluate the efficiency of the dynamic merging algorithm. It is shown that BEP outperforms the conventional TVoD interaction protocols.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47328/1/11042_2005_Article_6851.pd

Distributed multimedia systems

A distributed multimedia system (DMS) is an integrated communication, computing, and information system that enables the processing, management, delivery, and presentation of synchronized multimedia information with quality-of-service guarantees. Multimedia information may include discrete media data, such as text, data, and images, and continuous media data, such as video and audio. Such a system enhances human communications by exploiting both visual and aural senses and provides the ultimate flexibility in work and entertainment, allowing one to collaborate with remote participants, view movies on demand, access on-line digital libraries from the desktop, and so forth. In this paper, we present a technical survey of a DMS. We give an overview of distributed multimedia systems, examine the fundamental concept of digital media, identify the applications, and survey the important enabling technologies.published_or_final_versio

Semi-automatic video object segmentation for multimedia applications

A semi-automatic video object segmentation tool is presented for segmenting both still pictures and image sequences. The approach comprises both automatic segmentation algorithms and manual user interaction. The still image segmentation component is comprised of a conventional spatial segmentation algorithm (Recursive Shortest Spanning Tree (RSST)), a hierarchical segmentation representation method (Binary Partition Tree (BPT)), and user interaction. An initial segmentation partition of homogeneous regions is created using RSST. The BPT technique is then used to merge these regions and hierarchically represent the segmentation in a binary tree. The semantic objects are then manually built by selectively clicking on image regions. A video object-tracking component enables image sequence segmentation, and this subsystem is based on motion estimation, spatial segmentation, object projection, region classification, and user interaction. The motion between the previous frame and the current frame is estimated, and the previous object is then projected onto the current partition. A region classification technique is used to determine which regions in the current partition belong to the projected object. User interaction is allowed for object re-initialisation when the segmentation results become inaccurate. The combination of all these components enables offline video sequence segmentation. The results presented on standard test sequences illustrate the potential use of this system for object-based coding and representation of multimedia

Omnidirectional view and multi-modal streaming in 3D tele-immersion system

3D Tele-immersion (3DTI) technology allows full-body, multi-modal content delivery among geographically dispersed users. In 3DTI, user’s 3D model will be captured by multiple RGB-D (color plus depth) cameras surround- ing user’s body. In addition, various sensors (e.g., motion sensors, medical sensors, wearable gaming consoles, etc.) specified by the application will be included to deliver a multi-modal experience. In a traditional 2D live video streaming system, the interactivity of end users, choosing a specified viewpoint, has been crippled by the fact that they can only choose to see the physical scene captured by a physical camera, but not between two physical cameras. However, 3DTI system makes it possible rendering a 3D space where the viewers can view physical scene from arbitrary viewpoint. In this thesis, we present systematic solutions of omnidirectional view in 3D tele-immersion system in a real-time manner and in an on-demand streaming manner, called FreeViewer and OmniViewer, respectively. we provide a complete multi-modal 3D video streaming/rendering solution, which achieves the feature of omnidirectional view in monoscopic 3D systems