Streaming an H.323 Videoconference

Streaming Videoconferences

Egon VerharenTNC2004 H.323 TrainingJune 11, 2004Rhodes, Greece

Streaming

Streaming is the one-way delivery of digital content from a streaming server to a streaming client in a continuous, paced, and controlled flow.

Streaming alleviates the need to download an entire media clip as a file.• Live events don’t exist as a file yet!• Allows playing to start before download is completed• Protects copyright

Streaming a Videoconference

Streaming a videoconference makes it possible for any number of people to view a conference – either live or recorded for on-demand access.

Viewers use desktop computers with standard media players such as Real, Windows Media, or QuickTime.

What Kinds of ThingsCan You Do?

Key individuals participate interactively by videoconference; a larger audience views the live stream.

Save the proceedings of a meeting. Make a class or lecture available on-

demand for student review. In fact, maybe all you want to do is stream

an event – you don’t need to videoconference. You have a videoconferencing appliance in the room, and…

Interactive for Live Events

Streaming is a one-way delivery of media.

Participants in a live, streaming event can participate interactively (give feedback “the other way”) by:•E-mail to a conference facilitator•On-line chat

Four Methods to Stream a Videoconference

All-in-one box solutions

Combination of videoconferencing terminal and standard streaming encoder

Videoconferencing appliances with built-in H.26x/G.7xx multicast streaming

Application service provider

All-In-One Box

As either an• H.323 terminal and a streaming server, or • H.323 MCU and streaming server.

These devices• Take the H.26x video and G.7xx audio out of an H.323 envelope and stuff into the envelope of a common streaming format such as Real, Windows Media, or QuickTime, and

• Serve the unicast or multicast stream.• Can store the stream for VOD.

All-In-One Box

Examples:• STARBAK Torrent VCG• FVC Conference Server with Streaming Support• Virtual Rooms Videoconference Service (VRVS)

Combo Terminal and Encoder

Two standard devices…• H.323 videoconference terminal• Streaming encoder

Are interconnected• A/V out of H.323 terminal into A/V input of encoder

Encoder can be just about anything• Real, Windows Media, QuickTime; or MPEG-1,-2,-4; unicast or multicast

Video can be recorded and stored for VOD

Terminals with Built-In

Some high-end terminals such as • Polycom FX• Tandberg 880

Can multicast the H.26x/G.7xx audio and video in standard streaming envelopes (QT, etc.).

No ability to record for VOD.

Application Service Providers

Many videoconference bridging service providers also provide a streaming option.

The technology that an ASP will employ will either be an All-In-One Box or a Combination Terminal and Encoder

Pros and Cons

Video and audio quality• CON: Both All-In-One Box and Terminals with Built-In repackage H.26x and G.7xx video and audio.

–H.26x & G.7xx are not optimized for streaming. The video quality is more susceptible to degradation due to network congestion than made-for-streaming formats such as Real and Windows Media encoders.

–H.26x doesn’t provide dynamic bandwidth adjusting capability like Real SureStream and Windows Intelligent Streaming.

Just because…

You’re getting a Real, QT, or WM stream out of an All-in-One Box, doesn’t mean optimized-for-streaming encoders are being used!

All-In-One Box and Terminals with Built-In DO NOT use the Real or WM encoders. They stuff H.26x and G.7xx encoded video and audio into Real, WM, or QT envelopes.

Pros and Cons

Video and audio quality• PRO: Solution Combo Terminal and Encoder uses optimized-for-streaming encoding formats.

–H.26x & G.7xx from the videoconference are decoded to baseband video and audio and re-encoded in an optimized-for-streaming format.

Pros and Cons

Networking• CON: Terminals with Built-In require IP multicast.

–Multicast is sparsely supported in the commercial Internet.

–Multicast support in university and commercial intranets is varied and typically not robust.

–Terminals with Built-In are only feasible if your audience is on multicast-enabled networks.

Pros and Cons

Networking• PRO: All-in-One Box and Combo Terminals and Encoders support IP unicast and multicast transmissions.

Pros and Cons

Operations and Management• CON: Combo Terminal and Encoder can be complex to manage

–Have to schedule and manage the encoder. Videoconference scheduling systems don’t support viewing the pair of devices as a single logical device.

Features• CON: Terminals with Built-In don’t have the ability to record a videoconference.

• CON: Data collaboration recording is difficult!!

fixed to speed of conference

flexible modem to broadband

fixed to speed of conference

Transmission speed

only w/ extra special tech

yesyesRecord for VOD

fair to poorgoodfair to poorPerf under net

congestion

requiresIP multicast

unicast ormulticast

unicast ormulticast

Networktransmission

simplecomplexmoderateManagement &

operation

simplecomplexmoderate to

complexInitial set up

Built-InComboAll-In-One 

moderate-to-low

highmoderate

Cost to support a large number of concurrent conferences

lowmoderatehigh

Cost to support a small number of concurrent conferences

Built-InCombo Term

& EncoderAll-In-One 

Internet2 CommonsVC Streaming Service

Utilizes STARBAK Torrent VCG all-in-one box

Available to any Internet2 Commons member who requests a conference

Internet2 Commons VC Streaming Service

Simple web interface• Video uses QuickTime, Windows Media Player, or

Real

Can add slides and chat, if you want them

Stream has about a 1 to 1 ½ second delay over the actual videoconference• Comparatively speaking, a very short amount of time