- From: Nigel Megitt <nigel.megitt@bbc.co.uk>
- Date: Tue, 30 Jan 2018 15:38:47 +0000
- To: Nigel Megitt <nigel.megitt@bbc.co.uk>, Janina Sajka <janina@rednote.net>, "public-tt@w3.org" <public-tt@w3.org>
- CC: Accessible Platform Architectures Administration <public-apa-admin@w3.org>, W3C WAI Accessible Platform Architectures <public-apa@w3.org>
Dear Janina, Following this, I have raised each comment individually for tracking purposes at: https://github.com/w3c/imsc/issues/315 https://github.com/w3c/imsc/issues/316 https://github.com/w3c/imsc/issues/317 https://github.com/w3c/imsc/issues/318 https://github.com/w3c/imsc/issues/319 https://github.com/w3c/imsc/issues/320 https://github.com/w3c/imsc/issues/321 You (and all) are welcome to follow and participate in the discussion there, otherwise we will discuss the issues, arrive at a WG disposition for each comment and request your comments on those dispositions. Kind regards, Nigel On 30/01/2018, 15:14, "Nigel Megitt" <nigel.megitt@bbc.co.uk> wrote: >Dear Janina, > >Thank you for sending these review comments. I will file each comment as a >separate issue on our GitHub repository w3c/imsc for the purpose of >continuing the conversation. > >Kind regards, > >Nigel > >(Chair, TTWG) > > >On 30/01/2018, 14:55, "Janina Sajka" <janina@rednote.net> wrote: > >>Colleagues: >> >>The Accessible Platform Architectures (APA) Working Group has reviewed >>your FPWD and offers our comments below. >> >>According to APA process, the formal APA decision on these comments is >>logged at: >>http://lists.w3.org/Archives/Public/public-apa-admin/2018Jan/0008.html >> >> >>Janina Sajka, APA Chair >> >><Begin comment> >> >>1. While we appreciate that TTML Profiles for Internet Media Subtitles >>and Captions 1.1 <https://www.w3.org/TR/ttml-imsc1.1/> is depending on >>Timed Text Markup Language 2 (TTML2) <https://www.w3.org/TR/ttml2/> , it >>should still include an introduction that guides the reader to a better >>understanding of its content. Such an introduction could respond to the >>following questions: >> >>a. Why are profiles needed for text-only and image-only >>captions/subtitles? >>b. What are typical use cases for a image-only captions/subtitles? >>c. What is the purpose of a presentation processor, and a transformation >>processor? >> >>2. There is a general issue with the way that an author specifies layout >>characteristics of captions and subtitles, such as font size, font >>family, line height, background and positioning. The spec describes the >>approach of the author specifying a 昆fixed layout昌 for captions and >>subtitles that the user cannot change. However, it must be possible for >>the user to overwrite the author易s choice of font size, or background >>color, for example. This is necessary for accessibility reasons, in the >>same way that browsers allow the user to change font size and background >>color. How can we find a good solution for these conflicting interests >>between author and user? We would like to get into a discussion with you >>on this issue. >> >>3. Section 2 Documentation Conventions (applies also to Timed Text Markup >>Language 2 (TTML2) <https://www.w3.org/TR/ttml2/> section 2.3). For >>accessibility of the spec, information such as whether an element is >>deprecated or obsoleted should not be indicated by color (or background >>color) alone (cf. WCAG 2.0 SC 1.4.1 >><https://www.w3.org/WAI/WCAG20/quickref/#visual-audio-contrast-without-co >>l >>or> ). >> >>4. Section 5.1 General. The method of associating a text profile document >>instance with an image profile document instance should be specified for >>interoperability reasons, and not be left open to the specific >>implementation. Also, the association should be in both ways, i.e. also >>from the image profile document instance to the text profile document >>instance. >> >>5. Section 6 Supported Features and Extensions. All font-related features >>are prohibited for the image profile. This seems to be an unnecessary >>restriction if the image profile contains images in SVG format which >>could be rendered differently based on the author易s choice of font >>characteristics. >> >>6. Section 7.7.3 itts:forcedDisplay. This seems like a temporary >>solution. Wouldn易t it be better to define semantic layers of information >>that each could be made visible and invisible at runtime as appropriate >>for the user? For example, the user may want to see either speech-only >>(subtitles), narration speech only (parts of subtitles), foreign-language >>speech-only (parts of subtitles) or any combination of them. >> >>7. Section 7.7.4 itts:altText. While we see this feature as useful for >>accessibility purposes, it should be mandatory for images rather than >>recommended only. As mentioned in the spec, one could take the pertaining >>text passage from the text profile document instance 〝 but (1) an >>accompanying text profile is not required, and (2) the alternative text >>for the image could be different from the textual caption. Therefore, the >>itts:altText element should always be specified, but it should be empty >>for decorative images (not clear if a 昆decorative image昌 used as a >>caption makes sense anyway). By requiring an itts:altText for every >>image, but allowing for an empty element in case of a decorative image, >>we would align it with the alt attribute in HTML5 for images. >> >><End Draft Comment> >> >>* ACTION TO TAKE >> >>This CfC is now open for objection, comment, as well as statements of >>support via email. Silence will be interpreted as support, though >>messages of support are certainly welcome. >> >>If you object to this proposed action, or have comments concerning this >>proposal, please respond by replying on list to this message no later >>than 23:59 (Midnight) Boston Time, Tuesday 23 January. >> >>Janina >> >> APA Tracking Notes >> >>apa-ACTION-2152: >> Assigned to: Gottfried Zimmermann >>https://www.w3.org/tr/ttml-imsc1.1/ >> >>Draft comments by Gottfried: >>http://lists.w3.org/Archives/Public/public-apa/2017Nov/0008.html >> >> >>------------------------------------------------------------------------- >>- >>---- >> >>Janina Sajka >> >>Linux Foundation Fellow >>Executive Chair, Accessibility Workgroup: http://a11y.org >> >>The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI) >>Chair, Accessible Platform Architectures http://www.w3.org/wai/apa >> >>> > >> Here is my proposed feedback to the Timed Text Working Group: >> >> >> <draft-feedback> >> >> >> 1. While we appreciate that [1]TTML Profiles for Internet Media >> Subtitles and Captions 1.1 is depending on [2]Timed Text Markup >> Language 2 (TTML2), it should still include an introduction that >> guides the reader to a better understanding of its content. Such >> an introduction could respond to the following questions: >> >> a. Why are profiles needed for text-only and image-only >> captions/subtitles? >> b. What are typical use cases for a image-only captions/subtitles? >> c. What is the purpose of a presentation processor, and a >> transformation processor? >> >> >> 2. There is a general issue with the way that an author specifies >> layout characteristics of captions and subtitles, such as font >> size, font family, line height, background and positioning. The >> spec describes the approach of the author specifying a 昆fixed >> layout昌 for captions and subtitles that the user cannot change. >> However, it must be possible for the user to overwrite the >>author易s >> choice of font size, or background color, for example. This is >> necessary for accessibility reasons, in the same way that browsers >> allow the user to change font size and background color. How can >> we find a good solution for these conflicting interests between >> author and user? We would like to get into a discussion with you >> on this issue. >> >> >> 3. Section 2 Documentation Conventions (applies also to [3]Timed Text >> Markup Language 2 (TTML2) section 2.3). For accessibility of the >> spec, information such as whether an element is deprecated or >> obsoleted should not be indicated by color (or background color) >> alone (cf. [4]WCAG 2.0 SC 1.4.1). >> >> >> 4. Section 5.1 General. The method of associating a text profile >> document instance with an image profile document instance should >>be >> specified for interoperability reasons, and not be left open to >>the >> specific implementation. Also, the association should be in both >> ways, i.e. also from the image profile document instance to the >> text profile document instance. >> >> >> 5. Section 6 Supported Features and Extensions. All font-related >> features are prohibited for the image profile. This seems to be an >> unnecessary restriction if the image profile contains images in >>SVG >> format which could be rendered differently based on the author易s >> choice of font characteristics. >> >> >> 6. Section 7.7.3 itts:forcedDisplay. This seems like a temporary >> solution. Wouldn易t it be better to define semantic layers of >> information that each could be made visible and invisible at >> runtime as appropriate for the user? For example, the user may >> want to see either speech-only (subtitles), narration speech only >> (parts of subtitles), foreign-language speech-only (parts of >> subtitles) or any combination of them. >> >> >> 7. Section 7.7.4 itts:altText. While we see this feature as useful >> for accessibility purposes, it should be mandatory for images >> rather than recommended only. As mentioned in the spec, one could >> take the pertaining text passage from the text profile document >> instance 〝 but (1) an accompanying text profile is not required, >> and (2) the alternative text for the image could be different from >> the textual caption. Therefore, the itts:altText element should >> always be specified, but it should be empty for decorative images >> (not clear if a 昆decorative image昌 used as a caption makes sense >> anyway). By requiring an itts:altText for every image, but >>allowing >> for an empty element in case of a decorative image, we would align >> it with the alt attribute in HTML5 for images. >> >> </end comments> >> >> >>-- >> >>Janina Sajka >> >>Linux Foundation Fellow >>Executive Chair, Accessibility Workgroup: http://a11y.org >> >>The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI) >>Chair, Accessible Platform Architectures http://www.w3.org/wai/apa >> >> > >
Received on Tuesday, 30 January 2018 15:40:06 UTC