Concepts

1
Concepts Techniques for Accessible, Closed
Captioned Web-Based Video
David Klein K. Fritz Thompson

• 10th Annual Accessing Higher GroundAccessible
  Media, Web and Technology Conference
• Boulder, Colorado
• November 7, 2007
• http//disability.law.uiowa.edu/lhpdc/publications
  /kleinpubs.html

2
Interactive

• Who are you?
• Why are you here?
• What would you like to know?
• What are your expectations from this workshop?

3
Overview

• Introduction to accessible web-based video
• Compression
• Captioning (activity)
• (Break?)
• QuickTime (activity)
• Our Flash player (activity)
• Embedding content in a web page

4
Introduction

• Law, Health Policy Disability Center
• Grant-funded research, technical support,
  training

5
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

6
Our Video

• http//disability.law.uiowa.edu/dpn/video/dpn_1120
  04/dpn_112004_index.html
• Over 100 hours of online video for training
• Mostly talking heads

7
Feature Choices

• Player choice
• Flash player (default)
• QuickTime
• Windows Media Player
• Uncaptioned versions
• Embedded in web page vs. standalone
• Automatic play vs. user initiated
• Resizable
• Metadata, transcript, supporting documents

8
Overview of the Technologies
9
Players

• QuickTime
• Windows Media Player
• Flash Player

10
The Technologies

• Clients and servers
• Plugins or whatever
• Downloading
• Embedding video in web pages
• Captioning
• Flash

11
Clients vs. Servers
Server
12
Server vs. Client

• Server
• Stores HTML, video, caption text, other files
• Files can be stored on different servers
• Some dynamic content (e.g., databases)
• Client
• Displays content
• Interface to the user
• Dynamic
• Assembles files / content into a whole
  presentation

13
Client View
Browser Window
Video
Captions
Embedded Player with Controls
Links to supporting documents
14
Embedded Captioned Video
Server
Client
Video File
Embed in HTML File
Combine Files in Player
Caption File
15
Captioning Technologies

• XML
• Extensible Markup Language
• SMIL
• Synchronized Multimedia Integration Language
• SAMI
• Microsoft Synchronized Accessible Media
  Interchange
• QuickTime caption file
• Apple
• DFXP
• Adobe Flash

16
Creating Accessible Video

• 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

17
Video Compression Examples

• Find folder ahg2007CD on desktop
• Open folder (double click)
• Double click index.html
• Select Compare compression methods

18
Web-Based Video Methods

• Download play
• Video downloads completely then plays
• Streaming
• Server sends packets of video to client
• Progressive download
• Video downloads, but starts playing as soon as
  possible

19
Download Play

• Pros
• Reduces bandwidth issues
• Can play back without freezes
• Download and store for later play
• Cons
• Wait for file to download before playing
• Can be a long time
• No copy protection
• Archive only not live video

20
Streaming

• Pros
• Short wait for start of video
• Can start in middle of video
• Cons
• High bandwidth required
• Freezes not uncommon
• Problems at client end (firewalls)
• Can be expensive
• Can copy protect
• Required for live video
• Useful for archived video

21
Progressive download

• Pros
• Short wait for start of video, depending on
  bandwidth
• Low bandwidth possible
• Store for later play
• Freezes possible but replay without freezes
• Copy resistance but no protection
• Archive only no live video