Multiplexing Team Members: Cesar Chavez Arne Solas Steven Fong Vi Duong David Nguyen

Streaming Protocols

TCP Transmission Control Protocol  Protocol used for reliable document transfer  HTTP (Hypertext Transfer Protocol) uses TCP as the protocol for reliable document transfer.  Unsuitable for video and audio because:  Imposes flow control  Unnecessary Message delivery

UDP User Datagram Protocol  UDP is the alternative to TCP.  UDP forsakes TCP's error correction and allows packets to drop out if they're late or damaged.  Access Problems (firewalls).

RTP  The data part of RTP is a thin protocol providing support for applications with real- time properties.  continuous media (timing reconstruction )  loss detection  security  content identification.

VDP  VDP is an augmented RTP with demand resend.  VDP creates two channels between the client and server.  One is a control channel.  The other channel is for the streaming data.

RTSP . RTSP is a communications protocol for control and delivery of real-time media.  It defines the connection between streaming media client and server software  Provides a standard way for clients and servers from multiple vendors to stream multimedia content.

RSVP  Protocol designed to allow the assignment of priorities to "streaming" applications.  Works by permitting an application transmitting data over a routed network to request and receive a given level of bandwidth.

Media Streaming  Comparison of Commercial Video Streaming Products  Commercial Video Servers  Research on Continuous Media Toolkits and QoS Architectures

Comparison of Commercial Video Streaming Products  Deliver highest quality video for a given bandwidth, lowest delay, no jitter(low frame loss), good audio/visual synchronization, high quality audio, and image resolution.  Best possible video quality over a range of networks/bandwidths without content duplication is highly desirable. This characteristic is referred to as scalability.  Commercial products offer two types of scalability.

Continued…  One is the encoding state. A range of encoding formats to choose from, which correspond to a range of bandwidths.  Two is the dynamic scalability based on the available bandwidth at the time. Where dynamic scalability is provided it is usually simple frame dropping.

Commercial Video Servers  High-end database-driven video servers are also available from companies like IBM, Oracle, SGI, Sun and Tektronix. These products should be considered for large scale applications or for serving large numbers of simultaneous stream.

Research on Continuous Media Toolkits and QoS Architectures  The following are the major research project investigating the use of scalable video compression to dynamically adapt to variable bandwidth, to ensure multimedia delivery.  Berkeley Continuous Media Toolkit  Application Level Gateway  Distributed Real-time MPEG Video Audio Player  Multimedia Communication Filters  Image and Advanced TV Lab, Columbia  DSTC SuperNova

Video Streaming Standards  H.261  H.263  MPEG1  MPEG2  MPEG4

H.261  H.261 is use for teleconferencing applications and is intended for carrying video over ISDN.  H.261 needs substantially less CPU power for real-time encoding than MPEG.  H.261 uses constant-bit-rate encoding.

H.263  H.263 is design for low bitrate communication.  H.263 expected to be use for wide range of bitrate and expected to replace H.261.  H.263 supports 5 resolutions, able to compete with MPEG standards.

MPEG-1  MPEG-1 offers VHS quality video at a bandwidth of 1-1.5Mbps.  The resolution id at 30 frames per second  MPEG-1 requires expensive hardware for real- time encoding.  MPEG-1 does not offer resolution scalability  MPEG-1 is not suitable for video conferencing

MPEG-2  MPEG-2 is a better standard than MPEG-1  MPEG-2 include support for higher resolution video and increased audio capabilities.  MPEG-2 offers broadcast quality and full screen video at a bandwidth of 4-18Mbps.  More expensive than MPEG-1 to encode and decode.

MPEG-4  MPEG-4 is still in its experimental stage  Compression scheme for video conferencing,  MPEG-4 can be use for multiplexing for transmission over different networks  MPEG-4 framework focuses on a language called MSDL

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