[Resending after subscribing to WHATWG list - apologies for the noise] Dear WhatWG, Jer, Eric, Silvia, Philip,
W3C Timed Text Working Group kindly requests you to consider the following proposal: --------------------- What? --------------------- We propose to specify an implementation of the text track cue API where the format of the cue data is HTML. The "cue type" is called in the following "HTMLCue". The default onenter() handler in the HTMLCue interface would attach the cue data to the target element; conversely the default onexit() handler would clear the target element's inner HTML. --------------------- Why? --------------------- Different file formats are used for the distribution of subtitles and captions in the HTML ecosystem. Currently only WebVTT has a defined Cue concept that is implemented by Web Browsers. It would extend the reach of accessible content greatly if the text track API could be used by any subtitle format. Options for a solution: 1) Mapping of other formats to VTTCues Although this may be a short-term option a lossless mapping is often not feasible and requires considerable knowledge of the source and the destination format. It would also need continuous alignment of each of the subtitle formats with WebVTT and vice versa. 2) Define a cue type for every subtitle format Even if these different cue type specifications would exist it is unlikely that browsers will support all different cue "specializations". 3) Define a generic cue type This cue type should be easy to implement by browsers and it should be possible to map the semantic to the scope of different existing formats. We think an HTML cue as a variant of the third option is the best solution. The strength of a generic HTML cue type is that, assuming that the way to render these cues is clearly defined somewhere, basically any kind of subtitle format that can be translated into HTML could be supported, as long as the browser, a client side JS or a server based solution does the translation work somewhere. One way to make use of the doc fragment is to place the doc fragment as an overlay over the video. The HTMLCue could be defined as an HTML extension. The HTML5 Spec itself does not need to be changed. It may be worth noting that under the hood some browsers already translate WebVTT to HTML and some client side JS solutions translate TTML to HTML. => Next Steps? We would appreciate learning your opinion about this with the goal of advancing this activity during W3C TPAC in October 2015. Please send any emails to public...@w3.org - if you would rather respond in private please reply directly to me at this address. Kind regards, Nigel Megitt, co-chair, W3C Timed Text Working Group
