This page is still under construction following the discussion on the forum. Send your comments to info@accessibility.nl.
Contents: Introduction | Procurement requirements | Matrix Overview | Additional General requirements | Terminology and definitions | captions | audio description | full text alternative | subtitles | sign language | audio dubbing | decorative video | What do you need to deliver | layers | How to make these files | Example Scenarios | Appendix: 1. relevant guidelines; 2. Legislation; 3. Procurement: what to ask for or offer; 4. Links
The Web Guidelines, WCAG and drempelvrij.nl all require the same set of guidelines for video and audio, so that looks easy. To make it even easier, different parties are working on tools to make the production of online video and audio as easy as dropping a coin in a Coke machine. Yust to make sure we all understand this the same way, we provide some guidance and instruments below. First an important question:
Ask for conformity with the Web Guidelines when you change or renew (parts of) your website or multimedia. Please have a look at the appendix for more information and precise checkpoints you can use in your procurement documents.
| WCAG 1-A |
WCAG 1-AA |
WCAG 1-AAA |
Web Guidelines |
WCAG 2-A |
WCAG 2-AA |
WCAG 2-AAA |
WCAG samurai |
|
|---|---|---|---|---|---|---|---|---|
| A Prerecorded | ||||||||
| 1 (Closed) Captions | X | X | X | X | X | X | X | X |
| 2 (Closed) Audio description | X | X | X | X | OR | X | X | X |
| 3 Full text alternative | OR | X | ||||||
| 4 Audio description | ||||||||
| 5 Sign language | X | |||||||
| B Live (Recorded/Archived) | ||||||||
| 1 (Closed) Captions | X | X | X | X | X | X | X | |
| 2 (Closed) Audio description | X | X | X | a | a | a | a | a |
| 3 Full text alternative | ||||||||
| 4 Audio description | ||||||||
| 5 Sign language | X | |||||||
| C Live (Not recorded/Not archived) | ||||||||
| 1 (Closed) Captions | X | X | X | X | X | X | X | |
| 2 (Closed) Audio description | X | X | X | a | a | a | a | a |
| 3 Vol tekst alternatief | ||||||||
| 4 Audio description | ||||||||
| 5 Sign language | ||||||||
| D Decorative | ||||||||
| 1 Only descriptive label | X | X | X | X | X | X | X | X |
| E Audio (incl. Podcasts - Recorded/Archived) | ||||||||
| 1 Captions voor talk | X | X | X | X | X | X | X | X |
| 2 Transcript for mainly music | X | |||||||
This is the Matrix of requirements for video and audio. Also use the additional general requirements in the section below (if applicable). The matrix and additional requirements are based on WCAG1.0, related techniques documents and other documents by stakeholders and experts on the web. X stands for required, a stands for alternative solution allowed in some cases, read more explanations in this article. For the Web Guidelines in the Netherlands, it is necessary to work conformant with the Rijksbesluit. To be ready for the future, we have also used the april 2007 version of WCAG2.0. The Section508 guidelines are very close to the WCAG1.0 priority 1, but missing the multimedia guidelines and swapping some priority 1 and 2 checkpoints.
Also added in the last column is part of the www.wcagsamurai.org proposal by Joe Clark e.a.. The first draft requires transcripts for talk: for large sites immediately, for smaller sites within a reasonable period. For Podcasts, WCAG Samurai adds: Lists of video or song titles etc. must be provided, and those must be published within 24 hours of publication of the podcast.
The additional general requirements in this section are taken from different sources as explanation and interpretation of the WCAG guidelines. They seem to be generally accepted on the web.
Synchronized text equivalents of audio information. They are mostly in the same language as the audio and convey not only speech content, but also non-speech information such as sound effects, music, laughter, and speaker identification and location. Captions shall not obscure or obstruct relevant visual information. Captions may sometimes be designated in packaged media as "subtitles for the deaf and hard of hearing (SDH)."
There is a difference between open and closed captioning (NCAM):
Silent movies need no captions, but then an explanation is necessary to explain that there is no soundtrack. This should also be done on the page that links to or embeds the video (source: wcagsamurai).
Live video and/or audio must have synchronized captions and audio descriptions. Webaim gives and explanation of live captioning, but there are many options and techniques these days.
Wcagsamurai errata writes: "Video or audio that is presented as an examples of written, spoken, or sign language (where the language itself or its use is the purpose of the recording, not the meaning of the words), including language-learning sessions and linguistic field recordings, do not have to be captioned, transcribed, or described".
Internet telephony, voice instant messaging and voice conversations between during gaming do not have to be captioned or transcribed. In the US, the Federal Relay Services provide deaf, hard-of-hearing, deaf/blind and or people who have speech disabilities with equal communication access. This includes captioning and/or dubbing of live (online) video and audio, but also of live telephony and messaging support.
Audio descriptions make video accessible to people who are unable to see it. It provides information about movements or actions which are important to the comprehension of the content and that cannot be understood from the audio information alone. They include information such as actions, characters, body language, background visuals, sets and on-screen text and graphics. WCAG1.0 calls them auditory descriptions. Audio descriptions are added mostly during natural pauses of the sound track. If necessary, the timing of the content may be lengthened for the description to be inserted. The difference between open and closed audio description has been descibed earlier under captions.
Videos with a soundtrack but without a visual component do not need audio description. You do then have to explain that there is not a visual component.
For Live video and audio (like sports, games etc) ensure that all visual content is described in the included audio. This could be done by the person speaking in the video or audio. Then, a seperate audio description is not necessary.
Because of the EU TV Without Frontiers Directive that also describes the necessity for accessibility of online media, it is relevant to look at the fcc regulation on video description for television (CFR Sec. 79.3(a)): "The insertion of audio narrated descriptions of a television program's key visual elements into the natural pauses between the program's dialogue". This is limiting the definition used by W3C in WCAG 1.0 that describes more information to be added in the audio captions.
Document including correctly sequenced text descriptions of all visual and audio settings, actions, speakers, and non-speech sounds. Also including transcript of all dialogue. The Full text alternative must also achieve the same outcomes as achieved by the interaction (if any) during the multimedia. Mostly, a screenplay used to create multimedia content meets this definition only if it is corrected to accurately represent the final multimedia.
The Full text alternative is introduced by WCAG 2.0 and does not offer conformance with the Dutch Webguidelines.
On screen synchronized text providing the translation of the audio information. Sometimes, subtitles are edited, for people using the language as a second or a foreign language, for visual learners, for beginning readers etc.
WCAG Samurai adds that "Videos in languages other than the main language of the surrounding page do not need to be translated by subtitling or dubbing" for conformance with the accessibility guidelines it could however be nice for other viewers or listeners."That includes sign-language videos, which also do not need to be translated".
Live captioning and subtitling can be done by specially trained stenographers using stenotype or velotype keyboards. Also voice recognition with or without an operator is used increasingly.
A language that uses a system of manual, facial, and other body movements as the means of communication, especially among deaf people. It is very well possible to automatically generate sign language but not all sign languages are supported and not all details can be used or understood. Mostly the sign language is projected on top of a video or audio file in the right or left lower corner of the viewscreen (depending on the content of the video).
A method to add to or replace the existing audiotrack of a videofile. Sometimes, it is used to completely replace the original soundtrack with a translation.
Joe Clark adds:".[..]...Dubbing can completely replace an original dialogue track, replace everything but some features (like songs), or can be added to an original track (e.g., running in a slight delay after the original language track, which has its volume lowered). "
Audio dubbing is not a part of the guidelines, but it may influence captions and audio descriptions. This is covered in the matrix.
If non-text content is multimedia , live audio-only or live video-only content ( like live video without sound from Amsterdam), a test or exercise that must be presented in non-text format , or primarily intended to create a specific sensory experience , then text alternatives at least identify the non-text content with a descriptive text label.
If your visitors do not support the main output because it is not WCAG/Web Guidelines conformant, like currently the Flash or other (proprietary) formats, you will have to provide alternative output. This paragraph decribes the fall back if the online video, audio or multimedia is not WCAG/Web Guidelines conformant. All of the following are required (if applicable):
There are players that support SMIL. Also some players can play video, captions and audio descriptions (like the VLC player).
We are working on this section. There are already some interesting links in the linkslist below
We are working on a first draft of this section with funding from the Bartimeus Foundation.
The Web Content Accessibility Guidelines version 1 (WCAG1.0) provide three checkpoints with relevance to multimedia and video in particular.
WCAG1.0 checkpoint 1.1
WCAG1.0 checkpoint 1.1: "Provide a text equivalent for every non-text element. (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video.The Web Guidelines add some success criteria to this:
The Unified Web Evaluation Methodology version 1.13 offers detailed tests to measure this WCAG checkpoint. This Methodology (UWEM) has been produced in a major European Cluster of 3 projects including more than 21 parties working in the field of accessibility from 8 countries. The tests include testing for alternatives for video and/or audio tracks to measure conformance with WCAG1.0.
WCAG1.0 checkpoint 1.3
WCAG1.0 checkpoint 1.3: "Until user agents can automatically read aloud the text equivalent of a visual track, provide an auditory description of the important information of the visual track of a multimedia presentation.[priority 1]"
To test this, the Web Guidelines add: "One of the following applies:
Please also use the tests proposed in UWEM for this guideline.
WCAG1.0 checkpoint 1.4
WCAG1.0 checkpoint 1.4: "For any time-based multimedia presentation (e.g., a movie or animation), synchronize equivalent alternatives (e.g., captions or auditory descriptions of the visual track) with the presentation."
The Dutch Web Guidelines propose the following success criteria, where all of the following apply:
Auditory descriptions are provided of all information in scenes, actions, and events that cannot be perceived from the sound track alone;
All significant dialogue and sounds are captioned, except if the Web content is real-time and audio-only and not time-sensitive and not interactive, then a transcript or other non-audio equivalent is sufficient;
Descriptions and captions are synchronized with the events they represent.
As an addition or as he calls it an errata, Joe Clark states that "all your videos with soundtracks must have captioning. Also, most or all of your videos must have audio description (depending on content). You have to transcript dialogue-heavy podcasts (but not music podcasts), and you can’t use text files or HTML as substitutes for captioning or audio description".
Please also use the tests proposed in UWEM for this guideline (see under section 6.1.1 for short explanation of UWEM).
The Web Content Accessibility Guidelines version 2.0 covers accessibility of video and audio under multimedia in seven checkpoints. For this paper, we used the April 2007 draft of WCAG2.0. There is a clear difference between prerecorded and live audio and video in the guideline. Captions are always provided. For level AAA, sign language is required in all cases.
We are currently working on section508 and the update, UWEM and other relevant documents.
An extensive overview of national policies and legislation in different EU countries can be found on the supportEAM website as outcome of the Support EAM project.
In general: Ask for full conformance with Web Guidelines: Requirements (Word document, 1620 Kb)
The Web Guidelines include all the priority 1 and 2 checkpoints from the W3C Web Content Accessibility Guidelines. Mostly very easy to evaluate yourself, but to limit the risk of expensive repair cost later, you could ask a third party to evaluate for you following an ISO 17020 accreditation procedure. A ranked list of Webbuilders who have proven to be able to build following the guidelines is also available. This could save you many headaches. Also the Gilde van front-end developers will produce front end developers knowing what to do. You can easily become a member if you are a front end developer and procurers can ask for certification papers. Note that the more detailed requirements below are covered already by the general conformance with WCAG priority 1 and 2 or the Web Guidelines above.
More detailed: Require conformity with the following guidelines in particular:
Indirectly, also the following checkpoints are relevant and have to conform:
Also visit the pages about making subtitles for online video in Magpie on this site.
The links below are not yet categorized. We will do this later but for now this gives you the opportunity to have a look at pages we think are worth a visit.
http://teitac.org/wiki/Audio_Video
http://www.cenelec.org/NR/rdonlyres/5C6E5124-6034-422A-
A1CC-62B2229746C3/664/FinalreportTVforAll.pdf
http://www.tiresias.org/guidelines/television.htm
http://www.w3.org/TR/WAI-WEBCONTENT/
http://www.w3.org/1999/10/tvweb-ig-charter
http://cnice.utoronto.ca/guidelines/caption.php
http://www.ofcom.org.uk/static/archive/itc/itc_publications/
codes_guidance/standards_for_subtitling/introduction.asp.html
http://www.ofcom.org.uk/static/archive/itc/itc_publications/
codes_guidance/standards_for_subtitling/subtitling_4.asp.html
http://www.fcc.gov/cgb/dro/video-description.html
http://www.hitech-projects.com/euprojects/mytv/
http://www.hitech-projects.com/euprojects/mytv/myTV%20Fina-
l%20project%20overview.pdf
http://www.tvhelp.org.uk/
http://www.digital-web.com/articles/captions_flash_video/
http://www.webaim.org/techniques/captions/
http://www.jeroenwijering.com/extras/readme.html#basic
http://www.jeroenwijering.com/?item=Flash_Video_Player
http://dotsub.com
http://en.wikipedia.org/wiki/Subtitle_%28captioning%29#Subtitle_formats
http://www.ofcom.org.uk/static/archive/itc/itc_publications/codes_guidance-
/audio_description/audio_1.asp.html
http://www.rnib.org.uk/xpedio/groups/public/documents/publicwebsite/-
public_audiodescriptionontv.hcsp
http://ncam.wgbh.org/webaccess/magpie/magpie_help/audiodescription.htm
http://ncam.wgbh.org/publications/adm/guideline_h.html
http://www.apple.com/education/accessibility/technology/texttrack.html
http://www.apple.com/education/accessibility/
http://klaus.geekserver.net/flash/streaming.html
http://www.videolan.org/vlc/streaming.html
http://www.streamalot.com/wm-embed.shtml
http://forums.mozillazine.org/viewtopic.php?t=206213
http://www.apple.com/quicktime/tutorials/embed.html
http://www.divx.com/divx/webplayer/
http://dltj.org/2007/02/update-to-embedded-web-video/
http://www.jeroenwijering.com/?item=Making_Video_Accessible
http://www.jeroenwijering.com/extras/accessibility.html
http://www.minvws.nl/video/
http://www.rnib.org.uk/xpedio/groups/public/documents/code/public_-
adclipadvertshomehtml.hcsp
http://www.projectreadon.com/
