Concepts & Techniques for Accessible, Closed Captioned Web-Based Video 10th Annual Accessing Higher Ground: Accessible Media, Web and Technology Conference Boulder, Colorado November 7, David Klein K. “Fritz” Thompson
Embedded Closed Captioning QuickTime Text Track QuickTime Pro required Embedded in video file itself Video & captions self-contained Easy to Deploy (1 file) May start faster in browser (1 file) Hard to modify Captions can’t be closed without script Can be “masked” (e.g., translucent)
Embedded Closed Captioning QuickTime Text Track Demo of embedding text track into QuickTime Also see WebAIM: uicktime/add_captions.php uicktime/add_captions.php uicktime/add_captions.php
Embedded Captioned Video – Single File Embed in HTML File ServerClient Video File with Captions
QuickTime Captioned Video SMIL file option Requires 3 files Relatively easy to modify captions and video Video and caption files can be reused Captions separate, so can be eliminated Harder to deploy
Embedded Captioned Video – Multiple Files Embed in HTML File ServerClient Video File Caption File Combine Files in Player
QuickTime Captioning & Deployment Video .mov file Caption file .txt QuickTime caption file SMIL .smi,.sml, or.mov Integrates video and caption files HTML Integrates video, captions, player, text, other files
Final Assembly (QuickTime) Video file videoname.mov Caption file videoname_captions.txt SMIL file videoname_smil.movvideoname_smil.sml videoame_smil.smi (avoid)
SMIL File Characteristics Use XML standards Tags case sensitive All elements closed xxx (open and close tags) (no explicit close tag; end with the slash) “SMILtext” identifier not standard
SMIL File Layout SMILtext SMILtext <smil> </smil>
SMIL File “SMILtext” tag, encoding, QuickTime association Header Metadata (video name, copyright info) Player layout (“region” sizes, background / text colors) Container IDs for linking parts Body Video duration Start (and end) times File locations Links to regions
SMIL and the Player Layout Root Layout Video region Text region
SMIL File Activity Handout: Activity 2: QuickTime Objective: Modify MAGpie files to assemble a captioned QuickTime video