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Concepts & Techniques for Accessible, Closed Captioned Web-Based Video 10th Annual Accessing Higher Ground: Accessible Media, Web and Technology Conference.

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Presentation on theme: "Concepts & Techniques for Accessible, Closed Captioned Web-Based Video 10th Annual Accessing Higher Ground: Accessible Media, Web and Technology Conference."— Presentation transcript:

1 Concepts & Techniques for Accessible, Closed Captioned Web-Based Video 10th Annual Accessing Higher Ground: Accessible Media, Web and Technology Conference Boulder, Colorado November 7, 2007 http://disability.law.uiowa.edu/lhpdc/publications/kleinpubs.html David Klein K. “Fritz” Thompson

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_ 112004/dpn_112004_index.html http://disability.law.uiowa.edu/dpn/video/dpn_ 112004/dpn_112004_index.html http://disability.law.uiowa.edu/dpn/video/dpn_ 112004/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 Clients

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 Embedded Player with Controls Video Captions Links to supporting documents

14 Embedded Captioned Video Embed in HTML File ServerClient Video File Caption File Combine Files in Player

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


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