Back to Earth

After some well-needed rest, it’s time for me to dive back into the world of WebVTT with team OSD in OSD700. There are only a handful of us this semester and there is a lot of work to do. Sounds like a fun time to me!

Our end goal is still to implement the WebVTT standard into Mozilla Firefox. This semester, each student is going to drive a different area of the implementation. Personally, I think this is a pretty good approach. I’d like to drive the DOM implementation of WebVTT. The Document Object Model (DOM) is a representation of the objects found in HTML documents. It has an API which is accessible through JavaScript. The DOM implementation will allow developers to use JavaScript to program their WebVTT-equipped web apps with ease. At least, that’s the plan.

WebVTT files are loaded into the DOM with the <track> element. The W3 Wiki describes how one uses the element. src is the location of the WebVTT file to use. You can also specify a kind although the effects of doing so are a bit unclear.

Much more useful is the actual HTML5 specification which pretty well details the <track> element in full. It also includes an IDL implementation of the DOM interface!

interface HTMLTrackElement : HTMLElement {
  attribute DOMString kind;
  attribute DOMString src;
  attribute DOMString srclang;
  attribute DOMString label;
  attribute boolean default;

  const unsigned short NONE = 0;
  const unsigned short LOADING = 1;
  const unsigned short LOADED = 2;
  const unsigned short ERROR = 3;
  readonly attribute unsigned short readyState;

  readonly attribute TextTrack track;
};

IDL stands for Interface Description Language, and that’s pretty well what it is. It’s a language used to define interfaces. That’s pretty well I know at this point.

Right now, I feel like I need to spend the new few days synthesizing all of this information. There is a lot to take in. However, I have devised a rough plan of the next few weeks!

Week 1 - Synthesizing information, Research on IDL and track

Weeks 2/3 - Look at other media DOM implementations such as video. Use this information to start trying to hack in the track element.

Week 3: Presentation 1

Weeks 4/5 - Continuing to hack track in

Week 6 - Presentation 2, hopefully at this point I’ll have something to show. Maybe an in class demonstration of some API calls from the developer console in Firefox.

Honestly, at this point, I have no idea how the rest semester will look. I gave myself a bit of time to hack the track element in as I believe it will not be an easy feat. IDL looks similar to Java. After that, testing, helping write DOM tests and whatever else I can do. As there are so few of us trying to accomplish quite a large task, I feel as if we will be changing job hats quite a lot over the next few months. While my hair doesn’t really work well with hats, I’m pretty excited for the next few months. I learned so much in the first semester, and this semester looks like a repeat in that category!