W3C home > Mailing lists > Public > public-html-a11y@w3.org > July 2010

[media] FW: Comments on Media Accessibility Requirements

From: John Foliot <jfoliot@stanford.edu>
Date: Thu, 22 Jul 2010 19:06:23 -0700 (PDT)
To: <public-html-a11y@w3.org>
Message-ID: <03b301cb2a0b$a67392b0$f35ab810$@edu>


Jim Allan (UAAG) forwarded this to me. Greg Lowney has provide some very
detailed feedback (which slipped my radar) which we should review as part
of the User Requirements. There is a lot of detail here, although much of
it is editorial in nature.  I will look to integrate as much as I can into
the Wiki page as quickly as possible, but active participants in the media
sub-group are encouraged to review and comment as required.


Thank you Jim and Greg.




From: Jim Allan [mailto:jimallan@tsbvi.edu] 
Sent: Thursday, July 15, 2010 10:14 PM
To: 'John Foliot'
Subject: FW: Comments on Media Accessibility Requirements




From: w3c-wai-ua-request@w3.org [mailto:w3c-wai-ua-request@w3.org] On
Behalf Of Greg Lowney
Sent: Tuesday, July 13, 2010 3:45 PM
To: WAI-UA list
Subject: Comments on Media Accessibility Requirements


As requested, here are some comments on the Media Accessibility
Requirements document, for those working on it. Most are minor editorial
issues but there are a few significant ones.

Comments on Media Accessibility Requirements



Last modified 2010-06-16

(I've used asterisk to mark comments that seem wide in scope, rather than
being merely about one particular item.) 


1.	I noticed that in two places the document skips heading levels,
and that the navigation links at the bottom are headings, which doesn't
seem appropriate. (The Firefox extension HeadingsMap highlights these
2.	Link to definitions for screen reader, AT, etc?
3.	* Making things available to AT is explicitly required in a very
few instances (e.g. Transcripts), which doesn't seem an intentional
choice. The two sections devoted to AT compatibility also call out a few
requirements, making it all rather confusing. I suggest making it a more
general requirement applying to almost everything (e.g. AT access to
caption text and its formatting, hyperlinks, etc.).
4.	* In general it doesn't distinguish expected steps (such as
keyboard access and customizable color) from steps that would be going
above and beyond core expectations (such as most of the steps listed for
Autism). This could really mislead and turn off readers who interpret
these as unrealistic expectations for most media. Are all listed
requirements really deserving of core-level status?
5.	* In general it could benefit from forward references to related
sections further down in the document.

Accessible media requirements by type of disability

6.	Re dyslexia mention synchronized highlighting of phrases in text
with audio.
7.	Why capitalize "Communication, Social Interaction, and Repetitive
8.	Incomplete sentence: "Since individuals on the autism spectrum can
be quite visual and learn effectively from social stories."
9.	In "Dexterity / Mobility impairment" should note that many users
rely on AT such as on-screen keyboards or speech recognition.
10.	In "Accessible media requirements by type of disability" I'd add a
section explaining that many people have multiple disabilities, and that
while deaf-blind is one category, there are others not specifically called
out here. Users for example may have low vision and difficulty typing, 
11.	The term "Sensory disability users" isn't used very much, and
might be considered less politically correct than "users with sensory

Audio Description: Voiced, Texted, and Extended

12.	* Consider grouping AD, TAD, and EAD in a single section on audio
descriptions, because they have a lot of overlap, are closely related, and
having three headings disproportionately emphasizes them over other
technologies that get a single section. Same with captioning and extended
captioning, and the two sections on AT compatibility.
13.	"They are written to convey objective information (e.g., a yellow
flower) rather than subjective judgments (e.g., a beautiful flower)" may
be correct but seems odd to me. I'm sure the script called for a beautiful
flower, rather than merely a yellow one, and the beauty is what the writer
and director were trying to convey, so it seems strange to actively avoid
conveying it. 
14.	These two bullet items seem redundant: "Closed descriptions can be
recorded as a separate track containing descriptions only, timed to play
at specific spots in the timeline and played in parallel with the
program-audio track."; "Some audio descriptions can be given as a separate
audio channel mixed in at the player." Are "track" and "channel" used here
as technical terms for different things, or is it just a linguistic
15.	"Audio description is available.; however regulation in the U.S.
and Europe is increasingly focusing on description." I think you mean,
"and" rather than "however". 
16.	The term "audio/video descriptions" seems misleading as (to me at
least) it sounds like it's discussing both audio descriptions of visual
content (e.g. a second audio track) and visual descriptions of visual
content (e.g. displayed text).
17.	Re list introductions like "Systems supporting audio/video
descriptions that are not open must", do you nowhere say that systems that
provide audio are required to support audio/video descriptions?
18.	"(AD-1) Provide an indication that descriptions are available, and
are active/non-active." seems useful but not necessarily a core
requirement. I believe that most television viewers who try closed
captions are used to just turning them on and waiting to see whether any
captions are actually displayed, which is actually more convenient than
requesting a display telling them whether there are captions and only then
turning on the caption display. 
19.	"The degree and speed of volume change should be under provider
control" what is meant by provider in this case? The term hasn't been used
in the discussion thus far.
20.	"(AD-8) Allow the author to provide fade and pan controls to be
accurately synchronized with the original soundtrack." is not really
enough information for novices like me. You might want to elaborate on the
goal. Is it to have the description sound like the narrator is standing in
the same location as the object being described? Also, one difference
between AD-8 and AD-13 is the former is all about author control, whereas
the latter gives control to both, but still fails to specify that the user
preference should override author preference.
21.	Is there supposed to be another document or section that would go
into more details on these requirements? Quite a few of them seem too
high-level to be useful; for example, "(TAD-1) Support presentation of
texted audio description through a screen-reader or braille device with
playback speed control and voice control and synchronization points with
the video."
22.	"(AD-10) Allow the user to select from among different languages
of descriptions, if available, even if they are different from the
language of the main soundtrack." I'd add "or from the general system
language setting.", for example choosing audio descriptions in your native
Farzi even if you're using English for your operating system's primary
language and listening to a film with Japanese audio.
23.	I suggest adding something early on letting readers know that
additional, advanced features are discussed in separate sections below.
For example, when I first read this I noted that it lacked allowing the
audio description track (speech or text) to pause and resume the media
with which it's synchronized. (For example, for video with audio being
watched when all viewers want the descriptions, the user might choose a
descriptive track that pauses the normal content in order to insert more
detailed descriptions than could fit in the main content's normal gaps.) I
wrote a comment about it, only later to find it was included in a separate
24.	Shouldn't the audio description requirements (or recommendations)
include the user ability to omit the video altogether, leaving only the
normal audio and descriptions?
25.	"Texted audio descriptions are provided as text files with a start
time for a description cue." It would help to mention any standardized
formats used for this purpose.
26.	Compare and contrast "(TAD-3) Where possible, support to present a
text or separate audio track privately to those that need it in a
mixed-viewing situation, e.g. through headphones." vs. "(AD-11) Support
the simultaneous playback of both the described and non-described audio
tracks so that one may be directed at separate outputs (e.g., a speaker
and headphones)." The key differences aren't conveyed clearly.
27.	"(TAD-4) Where possible, support for different options for authors
& users to deal with the overflow case: continue reading, stop reading,
and pause the video. Pause the primary audio and video. The preferred
solution from a user POV is to pause the video and finish reading out the
TAD." Consider rephrasing as "pause the primary audio and video until the
TAD catches up."
28.	In the discussion of texted audio description, might want to
clarify that every time you say "video" you of course mean both the
primary video and audio content.
29.	Reading top to bottom, I kept thinking that the document
overlooked variations until I encountered them further down. I would
recommend that the introduction to audio descriptions mention that
subsequent sections will discuss basic audio descriptions, texted audio
descriptions, and extended audio descriptions. Similarly, the discussions
of AD and TAD might allude to the fact that sometimes the descriptions are
too long for pauses, and refer the reader to the section on extended audio
descriptions below.
30.	EAD-2 (automatically pausing) would be impractical without EAD-3
(automatically resuming), so you might just combine them.
31.	TAD-4 and EAD-1 blur the boundary between TAD and EAD. If a system
supports TAD-4 it supports EAD, so might take out TAD-4 and refer the
reader to the EAD section.
32.	EAD section might explicitly say it applies to both AD and TAD.

Clear Audio (CA)

33.	"(CA-4) Potentially support pre-emphasis filers" I think you meant

Content Navigation by Content Structure (CN)

34.	"Short music selections tend to have versus and repeating
choruses" I think you meant "verses".
35.	In the section on structured navigation, your discussion of h1
isn't what I would have expected. In HTML documents, h1 is normally the
title of the current document, regardless of the scope of that document.
For example, an online book would typically be divided into multiple pages
and the h1 for the main page would be the title of the book, while the h1
for a chapter would be the title of the chapter, and if you can delve more
deeply and reach a page for a section its h1 would be the title of that
section. Thus, where you say "In a news broadcast, the most global level
(analogous to <h1>) might be 'News, Weather, and Sports.'" I would have
expected the h1 equivalent would more like "KIRO 7 Eyewitness News at
36.	"Audio productions of 'The Divine Comedy' may well include
reproductions of famous frescoes or paintings interspersed throughout the
text", did you mean video or multimedia productions? I don't expect many
audio productions to reproduce the frescoes and paintings :-)
37.	"Nowadays, these programs are based on the ANSI/NISO Z39.86
specifications." You might say "ANSI/NISO Z39.86 (DAISY) specifications"
in order to reference its commonly-used friendly name.
38.	In the introduction to structured navigation, the final two
paragraphs (UAAG references) seem entirely out of place. 
39.	In some places the document interleaves requirements for authoring
tools (e.g. CN-1) with requirements for content players (e.g. CN-2), which
is a little confusing. 
40.	I think I could figure out what "transport bar" means, but then
two paragraphs later "navigation track" comes along and I'm not sure what
the difference would be.
41.	Shouldn't structural navigation requirements include providing the
user with a navigable table of contents?
42.	"(CN-1) Generally, provide accessible keyboard controls for
navigating a media resource in lieu of clicking on the transport bar need
to be available, e.g. 5sec forward/back, 30sec forward/back, beginning,
end" is in the h3 section titled "Content Navigation by Content Structure"
but isn't about navigating by structure, nor does it fit in the larger h2
section "Alternative Content Technologies".
43.	If you were going to include CN-1 saying that content navigation
controls need to be keyboard accessible, that would imply that all
sections discussing user input needs to have a similar requirement for
keyboard access. Seems better just to refer readers to the section on
keyboard access which requires it for everything, and perhaps provide a
non-exhaustive list of instances you think they might overlook.
44.	* Seems odd that there are a lot of things here that I don't
believe are in UAAG. For example, CN-9 requires the user be able to skip
or filter out ancillary content such as sidebars, but I don't believe
UAAG20 requires that Web browsers allow the user to exclude such things
from the keyboard navigation or voicing order.

Captioning (CC)

45.	"Captions are always written in the same language as the main
audio track." And yet, I've not seen DVD or set-top boxes distinguish
between same-language and different-language captions. Also, you should
discuss here the use of foreign language captions, rather than only
mentioning them in the lead-in sentence for the requirements. Also, CC-26
explicitly acknowledges that there can be be multiple tracks of captions
in different languages. 
46.	"Closed captions are transmitted as data along with the video.",
wouldn't the category of closed captions also include captions that are
pulled down only on demand, possibly from another source entirely, rather
than transmitted with the video? Or is there another term for that?
47.	".turn them on, usually by invoking an on-screen control or menu
selection" or a dedicated physical button such as on a remote control. 
48.	"Open captions are always visible; they have been merged with the
video track and cannot be turned off." Except by selecting a different
video track.
49.	Interesting to note that while users of closed captions may prefer
verbatim text, operas are usually supertitled using shortened versions of
the libretto, to make it easier for readers to follow along without
spending too much time reading each line. This is true even of
same-language supertitles.
50.	As noted above it's confusing to first mention subtitles and
foreign language subtitles in the lead-in to the requirements, without
introducing the concepts or clarifying that they'd use the same
technologies as same language captions.
51.	* "(CC-10) Render a background in a range of colors, supporting a
full range of opacities." With this and several similar requirements, do
you want to clarify that the caption author should be able to specify a
background color, or do you feel it would be acceptable for the player to
choose what it considers a background appropriate for the text color and
video background? Should the user be able to override caption attributes
such as these?
52.	There are several requirements for horizontal languages without
corresponding requirements for vertical languages. For example, should
CC-15 or a parallel equivalent require that captions can be positioned at
least a minimum distance from the side of the screen?
53.	"(CC-21) Permit the distinction between different speakers." An
example of one that requires more detail. For example, any system would
allow one to prefix strings with the name of the speaker, and you already
require the author to be able to put strings in different locations. Do
you mean markup so the rendering agent can apply automatic, distinct
formatting styles, or so that assistive technology examining the captions
can convey the distinctions to users through other means?
54.	The lists titled "Formats for captions, subtitles or
foreign-language subtitles must" and "Further, systems that support
captions must" should probably use parallel construction, as I assume they
both relate to all types of captions, including same language and foreign
language, and regardless of whether they're formatted as subtitles or
55.	A number of items in the list "Formats for captions, subtitles or
foreign-language subtitles must" seem to be discussing the systems that
display the captions rather than the formats for specifying them. It may
just be a matter of rewording a number of the items, such as changing
"(CC-1) Render text in a time-synchronized manner, using the audio track
as the timebase master." To "(CC-1) Allow the author to specify the time
and duration at which text is displayed, using the audio track as the
timebase master." and "(CC-11) Render text in a range of colors." to
"(CC-11) Allow the author to specify colors for ranges of text."
56.	The list titled "Further, systems that support captions must"
should probably include one or more requirements to support the wide range
of author-specified markup that caption formats are required to support.
For example, having a caption format that allows the author to specify
text color is wasted when a player ignores those settings. 
57.	Why is captioning the only section to distinguish requirements for
data formats from requirements for rendering systems? Wouldn't that
distinction apply just as much (or little) for audio description, sign
language, etc.?

Extended Captioning

58.	It might be helpful to give an example of how this could be used.
For example, an ancillary window could display a scrolling list of the
most recent hyperlinks to be provided in captions, so that the link
doesn't disappear after just a few seconds when the next set of captions
is displayed. 

Sign Translation

59.	"mixed with the video and offered as an entirely alternate stream"
should be in parentheses instead of commas.
60.	"(SL-3) Support the display of sign language video either as
picture-in-picture or alpha-blended overlay." in these clauses the use of
"or" leaves it ambiguous whether the system needs to support both methods
and allow the author to choose, or whether the system is allowed to
support only one of the options.


61.	I believe "Providing a full transcript is a good option in
addition to, but not as a replacement for, timed captioning" conflicts
with UAAG20 where we acknowledge situations where transcripts are more
appropriate than synchronized captions. For example, transcripts are
usually sufficient for pre-recorded audio-only media.
62.	"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." has inconsistent grammar: probably want to
delete "either".
63.	I would suggest avoiding the word "provisioning" because it's
jargon and there are other terms that are more widely understood. Also,
it's not used elsewhere in the document.

System Requirements

64.	This section could use an intro paragraph. I assume it's a
catch-all for requirements that don't fit into a single alternative
content technology, all of which were in the previous section. However,
the term "system requirements" parallels that used under "Captioning"
where it meant requirements for players as distinct from data formats, and
that's confusing, especially since other sections such as that on
assistive technology are certainly system requirements.  Any catch-all
section should probably be at the end rather than in the middle. 

Keyboard Access to interactive controls / menus

65.	As noted above, it should be made clear that access through
keyboards and keyboard emulators is not optional, despite the phrase
"Systems supporting keyboard accessibility must."
66.	The phrase "interactive controls / menus" in the title is
misleading, since it is not limited to things that are "interactive" as in
having input and output, and "controls/menus" implies things with visual
representation on the screen. For example, if a player supports navigation
using mouse gestures, those should also all have keyboard equivalents.

Granularity Level Control for Structural Navigation

67.	"(CNS-3) This control must be input device agnostic." We don't
talk about agnostic elsewhere, so might rephrase it. Since functionality
needs to be available through the keyboard (already required by KA-1) this
essentially says that all keyboard navigation commands need to also have
equivalents for every other input device (e.g. pointing devices, and on
some systems speech or gestures). Is that what you intended to require?
68.	Isn't this entire section redundant to the content navigation

Time Scale Modification

69.	This is the first list of requirements that isn't scoped with
"Systems supporting such and so must". Does it really rate being the only
universal requirement?

Production practice and resulting requirements

No comments.

Discovery and activation/deactivation of available alternative content by
the user

70.	Re "The user agent can facilitate the discovery of alternative
content by following the criteria", this is the first list of requirements
to be described as optional, with the word "can" instead of "must". 
71.	Most of these requirements are already covered in their
appropriate sections of the document.
72.	"(DAC-3) The user can browse the alternatives, switch between
them." Should be replaced by the newer UAAG wording.

Requirements on making properties available to the accessibility interface

73.	Should refer the reader to the section on assistive technology API
further down in the document, or better yet, come after it.
74.	"any media controls need to be connected to that API" should be
"any media controls and text content need to be."
75.	"On self-contained products that do not support assistive
technology, any menus in the content need to provide information in
alternative formats" I'm skeptical of seeming to limit this to menus when
it really means menus and other controls.
76.	"make accessibility controls, such as the closed-caption toggle,
as prominent as the volume or channel controls" As I commented on the 508
Refresh, while this is well intentioned, a quick review of remote controls
for televisions and set-top boxes indicated that most if not all give
special prominent for volume and channel controls, because they're
probably the most commonly used controls. I don't think that it is
necessary for dedicated caption and video description controls to be equal
in prominence, and thus tied for the most prominent controls on the
device. This is especially true in because many people who use captions
will turn them on and leave them on, rather than toggling them frequently.
77.	The sentences on remote controls and physical button layout don't
really fit the section title ("making properties available to the
accessibility interface"). 
78.	Technically, the closed-system requirements don't fit the title
either, but at least they thematically go with AT compatibility so the
title could be changed to better incorporate both.
79.	I really can't understand any of the requirements in this section
as they're currently written. For example, while "(API-1) Support to
expose the alternative content tracks for a media resource to the user,
i.e. to the browser" is clear with regard to alt text when displayed or
hidden, and captions as they're displayed, what does it mean with regard
to secondary audio tracks?

Requirements on the use of the viewport 

80.	Re "(VP-1) If alternative content has a different height or width
to the media content, then the user agent will reflow the viewport." This
seems more relevant to the container than to media per se. Is it talking
about when video is replaced by description or when a caption field is
added below the video field?
81.	If we're talking about containers hosting media, then it brings in
a few additional requirements not yet listed here, such as the ability to
move the keyboard focus into and out of media objects. 
82.	"(VP-5) Captions occupy traditionally the lower-third of the video
- the use of this area for other controls or content needs to be avoided."
This is one of the few "requirements" that is phrased as a recommendation.

Requirements on the parallel use of alternate content on potentially
multiple devices in parallel

83.	The requirements in this section are all about supporting
assistive technology, which doesn't fit with the title or introduction to
this section ("Requirements on the parallel use of alternate content on
potentially multiple devices in parallel"). The title and intro should be
Received on Friday, 23 July 2010 02:07:01 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 7 January 2015 15:05:12 UTC