Techniques for Creating Accessible, Closed Captioned Web-Based Video
California State University - Northridge
21st Annual International Technology and 
Persons with Disabilities Conference

Los Angeles, California
March 22, 2006

http://disability.law.uiowa.edu/lhpdc/publications/kleinpubs.html
Interactive
•	Who are you?
•	Why are you here?
•	What would you like to know?
•	What are your expectations from this workshop?
Overview
•	Introduction to accessible web-based video
•	Compression
•	Captioning (activity)
•	(Break?)
•	QuickTime (activity)
•	Windows Media Player (activity)
•	Our Flash player (activity)
•	Embedding content in a web page
Introduction
•	Law, Health Policy & Disability Center

Grant-funded research, technical support, & training

Our Needs
•	Provide accessible web-based training
•	Quality video with high quality audio
•	Closed captions
•	Transcripts
•	Supporting documents (PowerPoints, Handouts, etc.)
•	Different formats (QuickTime, Windows Media Player, Flash)
•	Efficient production, development, and deployment
•	Frustrated with “player wars”

Our Video
•	http://disability.law.uiowa.edu/dpn/video/dpn_112004/dpn_112004_index.html
•	Nearly 100 hours of online video for training
•	Mostly talking heads
•	Characteristics (user choice)
•	Start with Flash
•	Links to different players
•	Uncaptioned versions
•	Embedded vs. Standalone players
•	Automatic play vs. press a key to start
•	Resizable Players
•	Surrounding metadata, transcript, supporting documents

Players
•	QuickTime
•	Windows Media Player
•	Flash Player
The Technologies
•	Clients and servers
•	Plugins or whatever
•	Downloading
•	Embedding video in web pages
•	Captioning
•	Flash
Clients vs. Servers
Server
•	Server 
•	Stores HTML, video, caption text, other files
•	Files can be stored on different servers
•	Files
•	HTML page
•	Video file
•	Caption text file
•	Combining file
•	Supporting files (transcript, handouts, PowerPoint)
Client 
•	Displays HTML in browser
•	Launches players
•	Assembles and displays the pieces 
•	Video
•	Caption text 
•	Video player and its controls
•	HTML and surrounding content

Client View
Embedded Captioned Video
Captioning Technologies
•	XML 
•	Extensible Markup Language
•	SMIL
•	Synchronized Multimedia Integration Language
•	SAMI
•	Microsoft® Synchronized Accessible Media Interchange 
•	QuickTime caption file
•	Apple
•	Flash
•	Macromedia
Creating Accessible Video
•	Basic usability
•	Start with video / audio of highest possible quality
•	Acquire secondary audio source and/or CART (real-time caption) file if possible
•	Capture, edit and compress video
•	3 output formats: .mov, .wmv, and .flv
•	Attention to first frame
•	Black
•	Titling

Video Compression Examples
•	See “Compare compression methods” link on CD index.html file.
•	Copy CD to desktop (hold down Option key and drag CD icon to a space on the desktop)
•	Open the new folder
•	Double click index.html
Video Compression
•	Codecs
•	Compression – Decompression
•	File sizes
•	Uncompressed / raw
•	1 minute = 230 megabytes
•	Compressed
•	 1 minute = 0.5 – 10 megabytes
Video Compression Factors
•	Bandwidth
•	Amount of data that can be streamed over the Internet
•	Ability of client computers to play back
•	File size
•	Video vs. audio quality
•	Level of action / movement 
•	Subject activity
•	Camera movement
•	Transitions
•	Detail (patterns in background, faces) vs. pixelation
•	Colors (smooth or blotchy)
Video Delivery Options
•	Look for compression settings in compressor
•	Other settings
•	Download and play
•	No special setting
•	Streaming
•	Hinting
•	“Progressive download”
•	QuickTime setting
•	Inherent in Media Player (.wmv)
Compression Solutions
•	Progressive download unless copyright issues
•	300 KB/s minimum
•	Native frame rate (30 fps)
•	Audio – Qualcomm, PureVoice highest quality, or MP3 44,000 Hz, 16-bit
•	Avoid streaming unless live
Compressors Recommendations
•	Sorenson Squeeze 
•	Flip4Mac Studio (if Mac for development)
•	Alternates
•	QuickTime (.mov) – inexpensive but limited
•	Windows Media Encoder (.wmv) – free 
•	Flash 8 Video Encoder (.flv) – comes with Macromedia Flash 8
•	Flip4Mac Plugin for QuickTime (.wmv) – $99
Additional Compressors
•	Discreet Cleaner 
•	Not being developed
•	Canopus Procoder (Win)
•	May not do .flv files
•	Apple Compressor (Mac)
•	Comes with Final Cut Pro
•	May not do .flv
•	Compression Master (Mac)
•	Adobe Premier (Win)
•	May not do .flv

Bandwidth
•	Low bandwidth 
•	Dialup connections
•	Possibly slow DSL
•	Heavily used networks
•	28 KB/s to 128 KB/s
•	High bandwidth
•	DSL, Cable, T1
•	128 KB/s to 512 KB/s and more
Compression Accessibility Issues
•	Low bandwidth positives
•	Small file sizes for downloading to hard drives
•	Low bandwidth negatives
•	Small display size
•	Pixelation and artifacts (low quality video)
•	Poor sound quality
•	Jerkiness, freezes, dropouts, no connection at all 
Compression Accessibility Issues
•	High bandwidth positives
•	Larger display sizes
•	Better quality video
•	High sound quality
•	High bandwidth negatives
•	Large file sizes harder to download to hard drives
•	Large files sizes can put stress on the server – slower page loading
•	Jerkiness, freezes, dropouts, no connection at all when connection slow
Download and Play
•	Wait for file to download before playing
•	Can be a long time
•	Freezes possible but can play back without freezes
•	Download and store for later play
•	No copy protection
•	Archive only

Streaming
•	Short wait for start of video
•	High bandwidth required
•	Fast server or multiple servers
•	Special network settings may be needed (multiple connections)
•	Fast connections
•	Freezes not uncommon
•	Problems at client end (firewalls)
•	Can copy protect
•	Needed for live video
•	Possible for archived video

“Progressive download”
•	Short wait for start of video, depending on bandwidth
•	Slow connection possible
•	Freezes possible but can be replayed without freezes
•	Download and store for later play
•	Copy resistance
•	Archive only