mattgarrish
commented
2 years ago This has been partially clarified in the EPUB 3.3 revision, @Jeffxz, although there's no guarantee of support beyond ID referencing.
The definition of the text element's src attribute now reads:
The value MUST be a [path-relative-scheme-less-URL string](), optionally followed by U+0023 (#) and a [URL-fragment string]().
https://w3c.github.io/epub-specs/epub33/core/#sec-smil-text-elem
And the reading system spec now says:
When presented with a Media Overlay [text element]() [[!EPUB-33]] whose src attribute references a [target element]() [[HTML]] or SVG Fragment Identifier [[SVG]], Reading Systems SHOULD ensure the referenced element is visible in the [Viewport](). Reading Systems MAY support other fragment identifier schemes.
https://w3c.github.io/epub-specs/epub33/rs/#sec-rsconf-rendering-text
The question that still needs to be solved, as you've figured out, is how ranges should be identified. Would you use CFIs or something else? That's the part that needs incubation before any stronger support statement could be incorporated.
Jeffxz
iherman
Introduction
I would like mediaoverlay to have a normal format to support range so that it will not require publisher to wrap text with html element specifying id attribute to map to audio clip. Or if there is already such a way to define this in spec then I would like to know.
who will benefit from the use case Content creator and reading system
what is the use case So it will be easier to map each word to audio clip without adding HelloWorld
how I will benefit from the use case There are a lot of benefit to have range in text. For example if content creator would like to map audio clip to each word then we don't need to wrap each word one by one. And it will be possible to use tool to generate smil automatically.
Detail
Use this smil as example it matches this text for one word. If we use span like this then it would be very difficult for reading system to highlight each word accordingly.
I searched around MediaOverlay but can see text src only can apply to IRI then we have a few problems.
IRI does not prevent us from defining range like http parameter for example
http://example.org/ebook1?path=//table[1]/tr[1]/td[2]&start=412&end=414but it is not well defined that can be used as contract between content creator and reading system. Also it can only deine very simple data type. (maybe serialize a json string to one parameter? But still need a definition)The serialization format for selector. The Text Position Selector are very close to what I am looking for but it does not have dom range. While the Range Selector does not seem to have character offset which a DOM Range does support.
So I wonder if could find a way to map certain word to audio clip without adding more html element.