Next Generation Streaming

What is Streaming?

On-line Playback of multimedia data

 Remote Playback vs. Local Playback

 Bi-directional(ITV) vs. Uni-directional(VoD)

 Unicast vs. Multicast

 Streaming Requirement

 Excessive Space Requirement

 ATSC(19.2MBits/sec) movie of 110 minutes: 15 GBytes

 Excessive Bandwidth Requirement

 ATSC: about 19.2 Mbits/sec, MPEG1/MPEG4: approx. 300Kbits/sec, MPEG2: about 10 Mbits/sec

Markets in Multimedia Streaming

 Worldwide growth of digital STBs(Feb. 8, 2001­ MRG, Inc.) 

 > $11.5 B in annual sales in 2004, over 140 M units by 2004.

 Growth of related digital services > $11 B (annually) by 2004.

 in aggregated new revenues > $54 B by 2004. 

 service revenues

 Electronic Program Guides (EPG)

 Personal Video Recorders (PVRs)

 Video-on-Demand (VOD)

 Interactive TV (ITV)

 Pay per View (PPV) 

 Companies

 NDS, Sony, TiVo, Motorola, Microsoft, Pace, Sarnoff, DirecTV, EchoStar, Hughes, Philips, Broadcom, Intel, National Semiconductor, Liberate, OpenTV, nCube, AOLTV, WebTV, Scientific Atlanta, Thomson, CacheVision, NBC, Wink, RespondTV and many others. 

Components of Streaming: from Technology Aspect

Components of Streaming: from Developer’s Aspect

History of Multimedia Technology

 Early 90’s: Local Playback of Multimedia Contents(OS issues)

 File System

 Resource Allocation

 Call Admission Control in single address space

 Mid 90’s: Remote Playback of Multimedia Contents(NW Issues)

 RTP/RTCP/RTSP

 Synchronization

 Bandwidth Guarantee on Network

 Smoothing

 Late 90’s: Contents Management and Mobile Issues

 Image Processing(Transcoding)

 Pattern Matching(DB Search)

 Authoring Tool

 Multimedia in Mobile Environment

 Heterogeneous Support(Scalable Encoding, Layered transmission)

Market Trends

Next Generation Streaming Support 

 Support for Heterogeneous Terminal

 Few tens of Mhz – Ghz terminal

 Support for Heterogeneous Network

 Few tens of Kbits/sec – Several tens of Mbits/sec

 Support for RASUM

Distributed Scalable Streaming Server

Component Technology: Server

Multimedia Streaming: Server/Client

 Streaming Server

 Difficult to provide Bandwidth Guarantee

 Bursty traffic

 CPU scheduling: Legacy TS approach is not feasible.

 File System: Legacy UFS does not fit.

 How to configure the system to support +1 M users.

 Client

 Heterogeneous Terminal: PDA, Notebook, Desktop

 Heterogeneous Network: T1, xDSL, Cable Modem, POT, IMT-2000

 Wired/Wireless, Static/Dynamic Connection

 Efficient codec to run on light weight processor( < 33 MHz)

Issues

 Adaptive stream QoS management technology for heterogeneous network/client environment

 Support multiple speed playback

 TCP friendly congestion control mechanism for multimedia streaming

 Operating Systems Kernel optimized for streaming

 Clustered File system technology optimized for multimedia streaming operation

 Light weight I/O technology which can handle hundreds of terabytes data

 Load Balancing

Execution Environment

 분산 실행환경

Serve Architecture

System Components

 Session

 System Resource Manager

 resource allocation/scheduling for QoS guarantee

 Component: CPU, Disk, Memory, NIC

 QoS Mapper

 Map QoS metric to system resource metric

 (25fps, 600*480, 1.5Mbps)  Memory(1.5Mbps) , CPU (5%)

 Call Admission Control

 request 요청시, QoS factor 가 변경시 ( ex, Fast forward, backward,.. ), 수락/거절 결정

Client Architecture

Session Management Algorithm

Session Management Algorithm

 Thread per session/Thread per Resource

 Issues: Synchronization between threads

File System for Streaming

 Typical Streaming Operation

 Sequential Read

 Occasional Fast-Forward, Fast-Backward, Pause

 Characteristics of Streaming Operation

 Bandwidth Guarantee

 Minimize Delay variances

 Minimize Latency

 Make the file structure flat  Reduce seek overhead

 Minimize Delay Variation

 File Structure should remain the same with the change in the file size.

 UFS design philosophy

 Handling wide variety of file size without loss of disk space

 Optimized for random I/O

 File System for Multimedia Streaming

 Minorca(U. of Oslo, Norway), MMFS(SUNY Stony Brook, USA), Presto(U. of Minnesota, USA), SMART(Hanyang U., Korea)

 Tigershark(IBM Almaden), Tiger(Microsoft)

Server: Architectural O/S issues

 Running entire stack on a general purpose SMP

 No direct disk to NIC transfers

 Bus based architecture

 O/S may cause queues in wrong places

 O/S supported I/O, IPC and synchronization are typically very inefficient

Server: Load Management Issues

 Symmetric Architecture vs. Layered Architecture

 Layered Architecture: Easier to manage, configure, engineer, but performance implication is not clear

 Load Distribution for Symmetric Architecture

 Client Based Approach(Netscape Access)

 Round Robin DNS(CISCO’s LocalDirector, Cisco’s Distributed Director)

 Dispatcher Based Approach(IBM Network Dispatcher)

 Server Based Approach(Scalable Server WWW)

Server: Content Management Issues

 Large Facilities built as loosely connected clusters of servers

 Significant overheads of contents support

 NFS mounting  Bottleneck, single point of failure

 Full Duplication  Consistency management overhead

 Content Partitioning  Traffic distribution difficult and single point of failure

 File Cached in every server  Nonscalable

 Content partitioning difficult to handle because

 Shifting demand phenomenon

 Heterogeneous servers

Server: Layered Architecture

 Number of Machines in each layer?

 How to maintain state information across the layer?

Multimedia Streaming: Network

 QoS Guarantee

 RTP/RTSP/RTCP

 Diffserv(PHB)

 Intserv(RSVP)

 MPLS

 Adaptive Streaming

 Scalable Encoding

 TCP friendly congestion control

 Transcoding

 Color  Black/White

 Picture  Text

 30 fps  3 fps

 Mobile Multimedia

 Smooth handoff

 Error Resilience

Issues in Network Support for Streaming

 QoS Guarantee

 Stochastic vs. Deterministic Guarantee  QoS model

 Diffserv: Router does not maintain the states of individual sessions.

 Intserv: Router maintains the states of individual sessions. E.g. RSVP

 Determining the timely flow of information

 Internet does not allow timely delivery of packet, but still mechanism for detecting timely delivery of data is required.

 RTP/RTCP, RTSP  The respective information is included in packet header.

 MPEG-4 over RTP

 Which information is to be maintained?

 In what format? (draft-gentric-avt-rtp-mpeg4-00.txt)

Issues in Network Support for Streaming

Issues in Network Heterogeniety Support for Streaming

 Network environment gets more diverse.

 T1, LAN, ADSL, Wireless LAN, 3 G mobile link

 Adaptive Streaming

 Media Transcoding

 Source Driven vs. Receive Driven

 Unicast vs. Multicast

 Scalable Multimedia Model

 Adjusting the rate

 Adjust Frame rate  Drop frames.

 Use hierarchically encoded streams.  Layered Transmission

 For live broadcast, adjust the encoding rate(e.g. QCIF)

Issues in Mobile Multimedia

 Source of Difficulties

 Wireless Link  Large Bit Error Rate(BER), Fading

 Mobility  Packet Route Changes

 Fluctuating Bandwidth

 Mobility

 hand-offs  Delay, Jitter

Issues in Mobile Multimedia

Presentation: SMIL

 SMIL(Synchronized Multimedia Integration Language, W3C)

 Feature

 Describe the temporal behavior of the presentation.

 Describe the layout of the presentation on a screen.

 Associate hyperlinks with media object.

 Objects: audio, video, animation, image, text, text stream, ref

 Features

 par

예)    <par>

           <audio id=“a” begin=“6s” src=“audio.ra” />

           <video id=“v” src=“video.rm” />

         </par>

 seq

예)     <seq>

            <audio src=“audio1” />

            <audio begin=“5s” src=“audio2” />

          </seq>

Presentation: Structure of MPEG4

Summary

 Next Generation Multimedia Streaming Technology

 Massive Scale Support  Clustered Solution

 Adaptive to Heterogeneous Network

 Adaptive to Heterogeneous Terminal Capability

 Presentation Technique

 Clustered Solution

 High Speed Storage Interconnect

 Content Partitioning

 Load Management

 Support for Heterogeniety

 Adaptive End to End Streaming Transport: Unicast vs. Multicast

 Scalable Encoding

 Presentation

 MPEG-4

 SMIL

 For further information, checkout

http://www.dmclab.hanyang.ac.kr/courseware/class/mmdbms/2000/index-mmdbms.htm

Appendix

Presentation: MPEG 4

 MPEG-4

 BIFS(Binary Format For Scenes): VRML like syntax

 Compressed binary format, Streaming, Animation, 2D primitives, Enhanced audio, Facial animation

 DMIF(Delivery Media Integration Framework)

 Session Layer Level Support for Multimedia Presentation

 Definition of transport and synchronization of stream

Presentation: Hierarchical Structure of MPEG 4