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What to consider about live webcasting

You only get 1 chance at a live event, make it count!

This article will explore some of the issues involved in running a live webcast. Why you want to stream live, bitrates, encoders, audiences, etc. You’ll have a better understanding of a live webcast and gain some alternatives to hiring an expensive CDN for a one-time event.

Why go live?

Why do you choose to have a live event? Is it because you want interactivity? Is it an event that happens that people need to see live? Or is it because your CEO said he wants his quarterly address available to all 40 live employees when he gives it?

There are good reasons to host a live event and there are bad reasons. Interactivity doesn’t really require a live stream. You can accomplish most things like chatting and taking polls without it being live.

know your audience

If it’s a corporate event, chances are your attendees will need to attend. However, if it’s a concert or sporting event, make sure you know who your audience is and if they’ll be able to attend. It sounds great to have a live concert for a band on a Friday night, but consider this; Is the audience between 15 and 25 years old? If so, they’ll probably be out Friday night and not at home in front of their computers to watch a concert.

It would be better to offer the concert as a pay-per-view or VOD event that people can watch at their leisure.

Know your encoding options

First choose whether it is a Windows Media or Flash event. What about RealMedia (really, does anyone use RealMedia anymore?). What about QuickTime? It is gaining popularity due to the iPhone, the problem is that not many providers support Darwin live streaming (check with them for the next 6 months though).

Once you’ve chosen a format, choose an encoder. For Flash Live Encoding, you can use Adobe’s Flash Live Encoder and a high-end computer. This product is fine for most consumer applications. You are really limited by the power of your computer. There is no Mac version available, so you need to be on a Windows machine.

A better option for Flash Live encoding is On2Flix Live encoding software or the Sorenson Squeeze Live product. Both will offer higher quality video and more flexibility.

You are still at the mercy of your computer. So I suggest you get the biggest and baddest computer you can when using a software live encoder. Throw in as much CPU, RAM, and video memory as possible. Please use a SATA or Firewire hard drive running at least 7200RMP.

You should also consider how you connect your camera source to the computer. Do not use a simple commercial webcam or analog to USB device. These are fine for home movies, but for professional video you should look into a Prosumer HD camcorder or a high-end encoding capture card like the Ospry card.

For a hardware live encoding solution, check out Digital Rapids, Vbrick or Newtek products. Digital Rapids has a cool new product called the TouchStream Appliance. It is a portable stand-alone hardware encoder perfect for field productions.

Windows Media/Silverlight Encoding

Try Windows Media Encoder or for Silverlight encoding try Microsoft Expression

For WM/Silverlight hardware encoding, choose a Vbrick, Digital Rapids (in some cases), or Tricaster device.

Watch your bitrate

Everybody wants everything in HD these days. There is a compelling reason to stream at 1.5 Mbps or higher. But is it really necessary? Consider this about bitrate: Many people can’t sustain much more than 1000 Kbps for any length of time. 3G wireless networks reach about 700 Kbps at best. You can get good quality full-screen video at about 750 Kbps.

If you want to get high bitrate, please use some new technologies. Microsoft and Adobe have bandwidth detection (variable bit rates). However, Silverlight now offers Microsoft Smooth Stream, which will dynamically change the video bitrate to match conditions at the player level. Adobe FMS 3.5 also uses dynamic live streaming which does more or less the same thing. The important thing to know about streaming at a high bitrate is to make sure you have enough upload bandwidth in place.

Test before going live

You have to be at your arrival one or two days before. If you are using a CDN, see if they offer any kind of live event monitoring service. Connect to your publishing servers and make sure you can maintain the necessary bandwidth for the event. If you have the option of multiple ingestion points, run ‘trace routes’ to the different servers and see which one is actually closest to you. The one for the city you are in does not necessarily mean that it is the closest

Talk to the IT coordinator on site, see if you can get dedicated bandwidth. My experience in conference centers is that the shared wireless internet offered is often below average. If you can’t get dedicated bandwidth, ask them what their usage is like during your event time. If it’s normally heavy, you may need to lower your bitrate to accommodate the poor connection.

Fire up your encoder and have people on different networks in different geographies watch your test stream. You only get 1 shot at this, and there are about a million moving parts that can break.

How do I get my signal across so people can see it?

You have many options. The first thing to consider is how big is my audience? Ultimately this will determine how much bandwidth and resources you will need. Use this equation:

(Bit rate) X (seconds) *

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8

Take that number and divide it by 1000, this will give you your number in MB. Then multiply that by the number of viewers and you’ll know how much bandwidth you use

* average number of seconds a person will watch, not the duration of the event

example:

500Kbps X 1800 (30 minutes)

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8

= 112,500 then divide by 1000 = 112.5 MB. That is the amount of bandwidth that 1 user will consume watching for 30 minutes.

If you will have more than 50 viewers, it makes sense to look into dedicated servers or use a CDN. If you plan to have more than 1000 viewers, then a CDN is almost a must.

But for those events with just a handful of viewers, look to free services like

Mogulus and Ustream. Or look for low-cost options like Amazon cloud computing with Wowza servers. Also check out Influxis, who can host your FMS server for you.

A one-off live event from a tier 1 CDN like Limelight or Akamai will probably set you back around $5000 or more, or they’ll ask you to sign an annual contract somewhere in the neighborhood of $12,000 or more.

That’s a wrapper!

There are many options for live webcasting. Check out WebEx, iStreamPlanet, On24, Multicast and more. Ask the sales rep how many live events they have hosted. If your answer isn’t “so many I can’t count,” then consider moving on.

Thank you,

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