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Part 1 RTF version - Law_ Health Policy _ Disability Center

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Part 1 RTF version - Law_ Health Policy _ Disability Center Powered By Docstoc
					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 qualit y
   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
 Freezespossible 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  p o s s ib le
 Freezes possible but can be replayed without freezes
 Download and store for later play
 Copy resistance
 Archive only
n ba ndwidth
 Slow connection possible
 Freezes possib le b ut ca n b e r epla yed without fr eez es
 Downloa d a nd stor e for later play
 Copy r es ista nce
 Ar chive only

				
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