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You only get 1 shot at a live event, make it count!
This article will explore some of the issues about doing a live web cast. Why you want to go live, bit rates, encoders, audiences, etc. You will have a better understanding of a live webcast and get some alternatives to hiring an expensive CDN for a 1 time event.
Why go Live?
Why are you choosing to have a live event? Is it because you want interactivity? Is it a happening event that people need to see live? Or is it because your CEO said that he wants his quarterly address to be available to the 40 employees live when he gives it?
There are good reasons to offer a live event and there are bad reasons. Interactivity doesn’t really require a live broadcast. You can achieve most things like chat, and poll taking without it being live.
Know your audience
If this is corporate event, then it’s likely your attendees will be required to attend. However if this is a concert or a sporting event, be sure to know who your audience is and if they will 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 15-25 year olds? If so, they are probably going out on Friday night and won’t be 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 the leisure.
Know your encoding options
First choose whether this is to be a Windows Media or Flash event. What about Real Media (really, does anyone use RealMedia anymore?). What about QuickTime? It’s gaining popularity because of the iPhone, the issue is, not too many providers support Darwin live streaming (yet, check with them over the next 6 months).
Once you have a format chosen, choose an encoder. For Flash Live Encoding you can use the Flash Live Encoder from Adobe and a high end computer. This product is OK for most consumer applications. You are really limited to the horsepower of your computer. There is no Mac version available so you must be on a Windows machine.
A better option for Flash Live Encoding is the On2Flix Live encoding software or the Sorenson Squeeze Live product. Both of these will offer higher quality video and more flexibility.
You are still at the mercy of your computer. So I suggest you get the biggest, baddest computer you can when using a software live encoder. Throw as much CPU, RAM, and Video Memory at it as possible. Use a SATA or Firewire hard drive which runs at least at 7200RMP.
You also need to consider how you connect your camera source to the computer. Don’t use a simple off the shelf Web Camera or an analog to USB device. These are OK for home movies, but for professional videos you should look at a Prosumer HD Video Camera or a high end encoding capture card like the Ospry card.
For a hardware live encoding solution, look at the Digital Rapids, Vbrick, orNewtek products. Digital Rapids has a cool new product called the TouchStream Appliance. It’s a portable standalone hardware encoder perfect for field productions
Windows Media/Silverlight encoding
Try the 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
Everyone wants everything in HD these days. There is a compelling reason to broadcast at 1.5Mbps or higher. But is it really necessary? Consider this about bitrate: Many people can’t sustain much more than about 1000Kbps for any length of time. 3G wireless networks at best do about 700Kbps. You can get full-screen good quality video at about 750Kbps.
If you want to go high bit rate, utilize some new technologies. Microsoft and Adobe both have bandwidth detection (variable bit rates). However, Silverlight now offers Microsoft Smooth Stream which will dynamically change the bit rate of the video to adjust for conditions at the player level. Adobe FMS 3.5 also uses dynamic live streaming which does about the same thing. The important thing to know about broadcasting in high bit rate is make sure you have enough upload bandwidth at your venue.
Test before you go live
You need to be at your venue a day or 2 in advance. If you are using a CDN, see if they offer some sort of live event monitoring service. Connect to your publishing servers and make sure you can sustain the bandwidth required for the event. If you have the option of multiple ingest points, run ‘trace routes’ to the different servers and see which one is really closest to you. The one in the city your in doesn’t necessarily mean it’s closest
Talk to the venue IT coordinator, see if you can get dedicated bandwidth. My experience in conference centers is that the shared wireless Internet offered is usually sub-par. If you can’t get dedicated bandwidth, ask them what their usage is like during the time of your event. If it’s normally heavy, then you may need to lower your bit rate to accommodate for the poor connection.
Fire up your encoder and get people on different networks in different geographies to watch your test stream. You only get 1 shot at this, and there are about a million moving parts in this that can break.
How do I get my signal out there so people can see it?
You have a lot of choices. The first to consider is how big is my audience? This will ultimately dictate how much bandwidth and resources you will need. Use this equation:
(Bit rate) X (seconds) *
Take that number and divide by 1000, this will give you your number in MB. Then multiple that by the number of viewers and you will know how much bandwidth you use
*average number of seconds a person will watch, not the length of the event
500Kbps X 1800 (30 min)
= 112,500 then divide by 1000 = 112.5MB. That’s how much bandwidth 1 user will consume watching for 30 minutes.
If you will have over 50 or so viewers, it makes sense to look at dedicated servers or using 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 into free services like
Mogulus and Ustream. Or look at low cost options like Amazon cloud computingwith Wowza servers. Also check out Influxis who can host your FMS server for you.
A one time live event from a Tier 1 CDN like Limelight or Akamai will probably cost you about $5000 and up, or they will ask you sign an annual contract somewhere in the neighborhood of $12,000 or more.
That’s a wrap!
There are lots of options out there for doing live webcasts. Look at WebEx,iStreamPlanet, On24, Multicast, and more. Ask the sales rep how many live events they’ve hosted. If their answer isn’t “so many I can’t count” then consider moving on.
write by Archibald