Getting Ahead of the CurveSCALABLE, ACCESSIBLE, ENTERPRISE-CLASS VIDEO ON THE WEB

WCAG Requirements

Perceivable Operable Understandable Robust

Media is multi-modal (sight, sound, interactive)

Media Accessibility Checklist (http://www.w3.org/WAI/PF/media-a11y-reqs/)

Accessible Media Requirements by Type of Disability Blindness

Low vision Atypical color perception (color blind)

Deafness

Hard of hearing

Deaf-blind

Physical impairment

Cognitive and neurological disabilities

Production and Delivery Requirements

Alternative Content Technologies

Captioning

Described video

Text video description

Transcripts

Extended video descriptions

Enhanced captions/subtitles

Sign translation

Clean audio

Content navigation by content structure

System Requirements

Access to interactive controls / menus Discovery and activation/deactivation of

available alternative content by the user Granularity level control for structural

navigation Time-scale modification Requirements on making properties

available to the accessibility interface Requirements on the use of the viewport Requirements on secondary screens and

other devices

Alternative Content Technologies

Alternative Content Technologies:Captions“Captioning is the process of converting the

audio content of a television broadcast, webcast, film, video, live event, or other productions into text and displaying the text on a screen or monitor. Captions not only display words as the textual equivalent of spoken dialogue or narration, but they also include speaker identification, sound effects, and music description.” (http://www.dcmp.org/captioningkey/)

Alternative Content Technologies:CaptionsIt is important that the captions are:

synchronized and appear at approximately the same time as the audio is delivered

equivalent and equal in content to that of the audio, including speaker identification and sound effects

accessible and readily available to those who need or want them

Captions can be either Open or Closed

While similar in construction, Captions and Sub-Titles are not the same thing.

Alternative Content Technologies:Captions WCAG Success Criteria

S.C. 1.2.2 Captions (Prerecorded) (A)

S.C. 1.2.4 Captions (Live) (AA)

S.C. 3.1.2 Language of Parts (AA)

S.C. 1.4.8 Visual Presentation (AAA)

UAAG Success Criteria S.C. 1.1.1 Render Alternative Content (A)

S.C. 1.1.3 Replace Non-Text Content (A)

S.C. 3.1.3 Retrieval Progress (A)

S.C. 2.11.8 Video Contrast and Brightness (AAA)

Alternative Content Technologies:Captions (Timing and Display)Formats for captions, subtitles or foreign-language subtitles

must:

Render text in a time-synchronized manner, using the media resource as the time-base master.

Be available in a text encoding. (e.g. UTF-8)

Support positioning in all parts of the screen - either inside the media viewport but also possibly in a determined space next to the media viewport.

Permit a range of font faces and sizes. Permit rendered text and backgrounds in a range of colors, supporting a full range of opacities.

Additional requirements supporting internationalization and visual display properties

Alternative Content Technologies:Captions Formats

WebVTT (dev.w3.org/html5/webvtt/)

TTML/SMPTE (http://www.w3.org/TR/ttaf1-dfxp / https://www.smpte.org/sites/default/files/st2052-1-2010.pdf)

Other formats exist:

Scenarist Closed Caption (.scc)

SAMI/SMIL (.smi)

RealText (.rt)

SubRip/SubViewer (.srt/.sbv)

Alternative Content Technologies:DescriptionsDescribed video contains descriptive narration of key

visual elements designed to make visual media accessible to people who are blind or visually impaired.

The descriptions include actions, costumes, gestures, scene changes or any other important visual information that someone who cannot see the screen might ordinarily miss.

Alternative Content Technologies:Descriptions WCAG Success Criteria

S.C. 2.4.6 Headings and Labels (AA)

S.C. 1.2.5 Audio Description (Prerecorded) (AA)

S.C. 1.4.7 Low or No Background Audio(AAA)

UAAG Success Criteria

S.C. 1.1.1 Render Alternative Content (A)

S.C. 1.1.3 Replace Non-Text Content (A)

S.C. 3.1.3 Retrieval Progress (A)

S.C. 2.11.8 Video Contrast and Brightness (AAA)

Alternative Content Technologies:TranscriptsA full transcript supports different user needs

and is not a replacement for captioning. A transcript can either be presented simultaneously with the media material, which can assist slower readers or those who need more time to reference context, but it should also be made available independently of the media.

Alternative Content Technologies:Transcripts WCAG Success Criteria

S.C. 1.2.1 Audio-only and Video-only (Prerecorded) (AA)

S.C. 2.4.6 Headings and Labels (AA)

S.C. 3.1.1 Language of Page (A) UAAG Success Criteria

S.C. 1.1.1 Render Alternative Content (A)

S.C. 1.1.3 Replace Non-Text Content (A)

S.C. 3.1.3 Retrieval Progress (A)

S.C. 2.11.8 Video Contrast and Brightness (AAA)

Alternative Content Technologies:Extended and Enhanced Extended descriptions work by pausing the video and program

audio at key moments, playing a longer description than would normally be permitted, and then resuming playback when the description is finished playing. This will naturally extend the timeline of the entire presentation

Enhanced captions are timed text cues that have been enriched with further information - examples are glossary definitions for acronyms and other intialisms, foreign terms (for example, Latin), jargon or descriptions for other difficult language. They may be age-graded, so that multiple caption tracks are supplied, or the glossary function may be added dynamically through machine lookup.

Alternative Content Technologies:“Above and Beyond” Clean audio

Content navigation by content structure Sign translation

Summary of Authoring Requirements

To be fully conformant to WCAG 2.0 (AA), you will require the following:

CaptionsVideo DescriptionsTranscripts

System Requirements

What is an HTML5 Media Player?

<video width=“800" height=“600" controls>

<source src=“MyVideo.mp4" type="video/mp4" />

<source src=“MyVideo.webm" type="video/webm" />

<track src=“MyCaptions.vtt" kind=“Captions" srclang="en" label="English" />

<!-- fallback for legacy browsers -->

</video>

The browser is the video player – the video player is the browser!

HTML5 anticipates author scripted & customized controls

Many HTML5 video players today use Flash players as a fallback

System RequirementsAccess to interactive controls / menus

Interactive controls and menus must be available to all users for all means in which the controls are exposed - no matter whether they are exposed by the user agent, or are scripted.

Controls must be device independent, so that control may be achieved by keyboard, pointing device, speech, etc.

System RequirementsDiscovery and activation/deactivation of available alternative content by the user Alternative content must be both

discoverable by the user, and accessible in device agnostic ways.

The development of APIs and user-agent controls should adhere to UAAG guidance.

System RequirementsDiscovery & activation/deactivation of available alternative content

In cases where the alternative content has different dimensions than the original content, the user has the option to specify how the layout/reflow of the document should be handled.

The user can browse the alternatives and switch between them.

Synchronized alternatives for time-based media can be rendered at the same time as their associated audio tracks and visual tracks

Non-synchronized alternatives can be rendered as replacements for the original rendered content.

Provide the user with the option to load time-based media content such that the first frame is displayed (if video), but the content is not played until explicit user request.

System RequirementsGranularity level control for structural navigation

A real-time control mechanism must be provided for adjusting the granularity of the specific structural navigation point next and previous. Users must be able to set the range/scope of next and previous in real time.

System RequirementsTime-scale modification

While all devices may not support the capability, a standard control API must support the ability to speed up or slow down content presentation without altering audio pitch.(This feature has been present on many devices, especially audiobook players, for years. )

System RequirementsMaking properties available to the accessibility interface (AAPI)

For user agents supporting accessibility APIs implemented for a platform, any media controls need to be connected to that API.

System RequirementsRequirements on the use of the viewport

The video viewport traditionally provides a bounding box for many of the visually represented alternative-content technologies, although some alternative content does not rely on a viewport. Remember when designing player ‘skins’ is that the lower-third of the video may be needed for caption text.

Summary of System Requirements

Controls must be accessible, via platform AAPIs

Alternate content must be discoverable, and able to be modified by the end user

Content navigation and content display should allow for personalization

Infrastructure & Production Requirements

Let’s Do Video!

Producing Accessible videos Streaming your Accessible videos Managing your Accessible video library

Caption & Description ResourcesOutsourcing

Captions 3PlayMedia (http://3playmedia.com)

Automatic Sync (http://www.automaticsync.com/caption)

CaptionMax (http://captionmax.com/)

National Captioning Institute (http://www.ncicap.org)

Described Video Bridge Multimedia

(http://www.bridgemultimedia.com/audiodescription/ )

Dicapta (http://www.dicapta.com/)

CaptionMax (http://captionmax.com/)

More resources (http://www.acb.org/adp/services.html)

Producing Accessible videosVideo Captioning SoftwareMAGpie (http://ncam.wgbh.org/invent_build/web_multimedia/tools-guidelines/magpie)

Media Access Generator is the original free caption and audio-description authoring tool for making multimedia accessible to persons with sensory disabilities.

Subtitle Workshop (http://www.urusoft.net/products.php?amp;cat=sw&lang=1)

The most complete, efficient and convenient freeware subtitle editing tool. It supports all the subtitle formats you need and has all the features you would want from a subtitle editing program.

Caption Generator (http://www.vttcaptions.com/)

Caption Generator lets you create, synchronize and edit .vtt captions.

Producing Accessible videosVideo Description SoftwareYouDescribe (http://www.youdescribe.org/)

Free web-based tool that allows anyone to record descriptions of YouTube videos and/or play previously described YouTube videos.

CapScribe Open (http://www.inclusivemedia.ca/captionme/)

Free Mac-based video editor for captioning and description

MAGpie (http://ncam.wgbh.org/invent_build/web_multimedia/tools-guidelines/magpie)

Media Access Generator is the original free caption and audio-description authoring tool for making multimedia accessible to persons with sensory disabilities.

Livedescribe (http://www.livedescribe.com/)

Video description software designed, prototyped and developed at The Center for Learning Technology.

Producing Accessible videosHTML5

Out of band<video controls>

<source src=movie.webm>

<source src=movie.mp4>

<track src=english.vtt kind=captions srclang=en>

<track src=french.vtt kind=captions srclang=fr>

<p>Fallback content here with links to download video files</p>

</video>

Producing Accessible videosHTML5

In Band

Producing Accessible videosHTML5

In Band - ToolsHandbrake (Captions)

CyberLink Power Director

Sony Movie Studio Pro

iMovie

Adobe Premiere Pro

Streaming your Accessible videosAdaptive StreamingMedia Server

Adaptive Streaming - HTTP (http://en.wikipedia.org/wiki/Adaptive_bitrate_streaming)

MPEG-DASH

Apple HTTP Adaptive Streaming

Microsoft Smooth Streaming

Adobe Dynamic Streaming for Flash

http://www.streamingmedia.com/Articles/Editorial/Featured-Articles/How-to-Produce-for-Adaptive-Streaming-81020.aspx

Streaming your Accessible videosReal Time Streaming Protocol (RTMP)Media Server

Helix DNA Server / Helix Universal Server :

RealNetworks' streaming server. Comes in both open-source and proprietary flavors.

RealNetworks commercial streaming server for RTSP, RTMP, iOS, Silverlight and HTTP streaming media clients

QuickTime Streaming Server:

Apple's closed-source streaming server that ships with Mac OS X Server.

Windows Media Services:

Microsoft streaming server previously included with Windows Server that uses RTSP modified with Windows Media extensions

Streaming your Accessible videosReal Time Streaming Protocol (RTMP)Media Server

Wowza Media Server:

Multi-format streaming server for RTSP/RTP, RTMP, MPEG-TS, ICY, HTTP (HTTP Live Streaming, HTTP Dynamic Streaming, Smooth Streaming)

Managing your Accessible video library

Not all Media CMS solutions are equal.

An accessible Media CMS supports the following:

Integrated upload and tracking of Captions, Video Descriptions, Transcripts and of course Videos

Integrated Adaptive Streaming

Supports/converts multiple codecs (.mp4, WebM)

Thanks!

Questions?

John Foliot

john.foliot@Deque.com

@johnfoliot