Hands on Guide to Webcasting

May 14, 2007Streaming Media East

2

The Goal

• Live at noon• Audience participation

– yes, that means you

3

What We Have To Do

• Planning– programming– production– network infrastructure– web presence

• Execution– a/v production– authoring– encoding

• Testing– everything – twice.

4

Rough Schedule

• Initial discussion (10 mins)• Planning (1 hour)

– basics (who/what/where/why)

• Execution (1 hour)– a/v production setup– a/v testing– encoding setup– encoding testing

5

Why Webcasts are Tricky

• They’re live– No second chance

• Additional hardware requirements• Additional personnel requirements• They test the limits of your streaming

infrastructure– Bandwidth– Server architecture (web & streaming)

• They’re expensive and therefore can be hard to justify

Are you ready?

7

First: Make the Business Case

• Who– is the audience?

• What– are we webcasting?

• Where– is the location suitable

• When– is there enough time to do it right?

• Why– is this the best way to address the need?

8

We need a crew.

• Executive Producer• Audio engineer• Videographer (camera op)• Encoding engineer• Host• Guest(s)

9

Planning

• Location– Size, power, access, union fees

• Signal Acquisition– On site connectivity, satellite

• Equipment– Usually best to work with a partner

• Crew– May come with equipment

• Presentation– Talent, Pre/post show, technical difficulties

• Network Infrastructure– host, bandwidth usage, encoding specs

10

• Production area• Stage• Audio• Video• Encoding

Setup

11

• Avoid ground hum– Placement or extra equipment

• Ambient mics– Absolutely for musical events

• Tape down loose cables• Use compression• Test!

Audio Setup

12

Setting Up A Gain Structure

• Make sure each piece of equipment operates in its optimal range

• Start with first piece of equipment and work through the signal chain

• set the input and output gain for each• Peaks at -3dB for analog, -10dB for

digital

13

Audio Production Tips

• Compression “evens out” audio levels – Protects your equipment from “spikes” in level– Attenuating loud sections enables overall signal

gain– “Fattens” audio– Hardware compressor is essential for webcasts

14

Compression Illustrated

15

• Tripods (heavy duty)• Risers if available• Lights

– 3-point?– Flat wash?

• White balancing (shading)• Test!

Video Setup

16

How Video Codecs Work

• Intra-frame compression– Just like a .jpg or .png file

• Inter-frame compression– Differences between frames are encoded

• Key frames– Entire frame is encoded– Uses a lot of bandwidth

• Difference frames– Only differences are encoded– Use relatively little bandwidth on low motion content

17

Video Production Tips

• Avoid unnecessary motion/changes– Use a tripod, use a tripod, use a tripod– Avoid moving objects in the background– Avoid special effects– Simple edits are best– Keep the number of cuts to a minimum

• Framing– Smaller screen, so frame tighter

18

Video Production Tips

• G-I-G-O• Use good video engineering practice

– If you don’t know, hire someone

• Good equipment, proper technique– If you don’t own it, rent it

• Lighting is essential– Nearly impossible to correct using software– Low-light = no light

19

Video Processing Techniques

• VGA vs. Television displays– VGA screens are far more detailed – Traditional video tends to look dark & washed out

• Adjust Brightness– Add gain to match screen to a TV monitor– Be careful if you’re going back out to the

broadcast world!

• Adjust Contrast– Adding a small amount is good; be careful though– Too much contrast adds grain (bad for codecs)

• Color– Increasing saturation a bit can be helpful

20

Encoding Setup

• Bit rate• Resolution• Capture card?• Encoding software?• Local Archive?• Push vs. pull encoding• Redundancy is key

– Ideally redundant connectivity– Extra equipment

• Multiple stream solutions

21

Authoring

• Link to webcast page from home page• Always offer a metafile link• If embedding, keep it simple• Test!

22

Authoring

• Problem: browsers don’t stream– Browsers don’t understand RTSP or MMS protocols– Browsers download entire file

• Solution: metafiles– Small file delivered via HTTP– Contains information about streaming file

4

Web Server

Streaming Server

1

2

3

5

23

Authoring - Metafiles

• QuickTime .qtl files

• RealSystem .ram files

• Windows Media .asx files

<?xml version="1.0“ ?><?quicktime type="application/x-quicktime-media-link“ ?><embed src=“rtsp://your.qtserver.com/YourStream.mov" />

rtsp://your.realserver.com/YourStream.rm

<asx version="3.0"> <entry> <ref href="mms://your.wmserver.com/YourStream.wmv" /> </entry></asx>

24

Distribution Techniques

• Redundancy is key• Robust load balancing required• Use multicast where appropriate• Usually best to work with a partner• TEST!

25

Distribution Methods

• Unicast/multicast to servers• Unicast/multicast to local clients

26

Countdown

• Test the audio• Test the video• Test the encoder(s)• Test the link(s)• Go live at least 10 minutes before event

begins, preferably 30 minutes

Liftoff?

28

Q & A

Thank YouSteve Mack

smack@luxmedia.com