Accessibility/Video a11y Aug09: Difference between revisions
(started updating with Feb 10 state) |
(added update Feb 10) |
||
| Line 30: | Line 30: | ||
=== Specifications === | === Specifications: associating external text === | ||
Specifications for how to associate out-of-band time-aligned text with a HTML5 video (and audio) tag as well as how to parse multitrack media files and expose the same attributes, DOM API and JavaScript API are in the making. | Specifications for how to associate out-of-band time-aligned text with a HTML5 video (and audio) tag as well as how to parse multitrack media files and expose the same attributes, DOM API and JavaScript API are in the making. | ||
| Line 44: | Line 44: | ||
Update Feb10: | Update Feb10: | ||
* a specification that was created from a discussion in the W3C Accessibility Task Force is available from: http://www.w3.org/WAI/PF/HTML/wiki/Media_TextAssociations | * a specification that was created from a discussion in the W3C Accessibility Task Force is available from: http://www.w3.org/WAI/PF/HTML/wiki/Media_TextAssociations | ||
* discussions about standard formats tend towards: SRT and DFXP | |||
=== Specifications: JavaScript API for multitrack media === | |||
Update Feb10: | |||
* a specification that was created from a discussion in the W3C Accessibility Task Force is available from: http://www.w3.org/WAI/PF/HTML/wiki/Media_MultitrackAPI | |||
=== Demo implementations using javascript === | === Demo implementations using javascript === | ||
Revision as of 11:12, 7 February 2010
Video Accessibility Status Aug 2009 & Nov 2009 & Feb 2010 update
by Silvia Pfeiffer
This is a status report on the progress of video accessibility. I thought I'd publish this snapshot since it is a nice collection of resources around where video accessibility stands right now.
Test File Collection
A collection of time-aligned text files for testing is starting to emerge.
Text files for video/audio in different formats are available from: http://svn.annodex.net/itext/elephants_dream/ and http://svn.annodex.net/itext/chocolate_rain/
These include:
- 34 srt files for captions/subtitles in 34 different languages for “Elephants Dream” Blender Foundation movie – these are good for tests of srt support and different charactersets (i18n)
- 1 srt file and audio recording of audio description in English for “Elephants Dream” – these are good to test audio descriptions for the blind in two different formats
- 1 srt file for chapter markers for “Elephants Dream” – this tests sectioning and direct access to chapters
- 1 lrc and 1 qttext file for lyrics for “Chocolate Rain” video and music file CC-licensed by Tay Zonday – this tests different file formats for text annotations and support of accessibility for audio
Further accessibility-related files have been added (Nov 09):
- all 34 srt files have been converted to utf-8 for use with Kate
- a script has been added to create Ogg Kate files and merge them with Ogg Video files - the binary files are not in the repository
- 1 audio description file which can also be added to a Ogg video file using oggz-merge
- added 1 subtitle file in SAMI Microsoft Synchronized Accessible Media Interchange format subtitle file and one in Substation2 format, thanks to Guillaume Olivrin
- added 1 sign language file in South African Sign Language provided by Nare Mmonwa
Further accessibility-related files have been added (Feb '10):
Specifications: associating external text
Specifications for how to associate out-of-band time-aligned text with a HTML5 video (and audio) tag as well as how to parse multitrack media files and expose the same attributes, DOM API and JavaScript API are in the making.
- an initial specification for out-of-band time-aligned text files for HTML5 video is available from https://wiki.mozilla.org/Accessibility/HTML5_captions
- initial discussions have been had on the mailing lists of the following communities: W3C HTML WG, WHATWG, W3C WAI-XTECH, Free ARIA community, Xiph accessibility
- Feedback and discussions are collected at https://wiki.mozilla.org/Accessibility/Experiment1_feedback
Update Nov09:
- an second specification for out-of-band time-aligned text files for HTML5 video is available from https://wiki.mozilla.org/Accessibility/HTML5_captions_v2, with a main change being the introduction of a structuring element itextlist
- Feedback and discussions are collected at https://wiki.mozilla.org/Accessibility/Experiment2_feedback
Update Feb10:
- a specification that was created from a discussion in the W3C Accessibility Task Force is available from: http://www.w3.org/WAI/PF/HTML/wiki/Media_TextAssociations
- discussions about standard formats tend towards: SRT and DFXP
Specifications: JavaScript API for multitrack media
Update Feb10:
- a specification that was created from a discussion in the W3C Accessibility Task Force is available from: http://www.w3.org/WAI/PF/HTML/wiki/Media_MultitrackAPI
Demo implementations using javascript
A collection of JavaScript implementations for associating time-aligned text with audio/video is starting to emerge.
There are demos at http://www.annodex.net/~silvia/itext/ - their open source code is available from http://svn.annodex.net/itext/.
The demos consist of the following:
- "Elephants Dream" with subtitles and captions, chapter markers, and textual audio annotations for screen readers
- "Elephants Dream" with a different video player skin to test video player controls accessibility
- "Chocolate Rain" as video with subtitles and as audio with lyrics
- "Elephants Dream" with a demonstration of how to directly jump to time offsets in videos through URL changes
Update Nov09:
- "Elephants Dream" following the second itext specification is available at http://www.annodex.net/~silvia/itext/elephant_no_skin_v2.html
Related open bugs in Mozilla
The following bugs relate to video and audio accessibility at Mozilla:
- "Support for Kate overlay streams in video tag" https://bugzilla.mozilla.org/show_bug.cgi?id=481529
- "Implement UI for subtitles on html5 video/audio" https://bugzilla.mozilla.org/show_bug.cgi?id=515898
- "Ogg Theora video with two audio tracks fails to play" https://bugzilla.mozilla.org/show_bug.cgi?id=516323
Publications
Silvia posted the following blog posts relating to video accessibility:
- “First experiments with itext”
http://blog.gingertech.net/2009/07/29/first-experiments-with-itext/
- “The different aspects of video accessibility”
http://blog.gingertech.net/2009/08/03/aspects-of-video-accessibility/
- “ARIA – A Brief Introduction”
http://blog.gingertech.net/2009/08/21/aria-a-brief-introduction/
- “Updated video accessibility demo”
http://blog.gingertech.net/2009/09/14/updated-video-accessibility-demo/
- “Open Standards for Sign Languages”
http://blog.gingertech.net/2009/09/16/open-standards-sign-language/
- “HTML5 audio element accessibility”
http://blog.gingertech.net/2009/09/16/html5-audio-element-accessibility/
New in Nov09:
- "New proposal for captions and other timed text for HTML5"
http://blog.gingertech.net/2009/10/06/new-proposal-for-captions-and-other-timed-text-for-html5/
- "Dealing with multi-track video (and audio)"
http://blog.gingertech.net/2009/10/17/dealing-with-multi-track-video-and-audio/
- "The model of a time-linear media resource for HTML5"
http://blog.gingertech.net/2009/11/23/model-of-a-time-linear-media-resource/
- "Manifests for exposing the structure of a Composite Media Resource"
http://blog.gingertech.net/2009/11/25/manifests-exposing-structure-of-a-composite-media-resource/
Also the following relate to media fragment addressing, which will enable a deeper interaction with audio and video and thus improve accessibility as well:
- “Jumping to time offsets in HTML5 video”
http://blog.gingertech.net/2009/08/19/jumping-to-time-offsets-in-videos/
- “Media Fragment addressing into a live stream”
http://blog.gingertech.net/2009/08/26/media-fragment-addressing-into-a-live-stream/
- “Demo of deep hyperlinking into HTML5 video”
http://blog.gingertech.net/2009/09/02/demo-of-deep-hyperlinking-into-html5-video/
- “URI fragments vs URI queries for media fragment addressing”
http://blog.gingertech.net/2009/09/08/uri-fragments-vs-uri-queries-for-media-fragment-addressing/
Talks given at:
- "WebJam 2009 talk on video accessibility"
http://blog.gingertech.net/2009/10/09/webjam-2009-talk-on-video-accessibility/
- "Web Directions South 2009 talk on HTML5 video"
http://blog.gingertech.net/2009/10/09/web-directions-south-2009-talk-on-html5-video/
- "HTML5 Video element discussions at TPAC meetings"
http://blog.gingertech.net/2009/11/16/html5-video-element-discussions-at-tpac-meetings/