February 10, 2010

Herdict-Firefox Integration and Better HTML Presentations

I recently wanted to create a short, two-minute and thirty second “pitch” for the Herdict-Firefox integration prototype I’m working on with Jennifer Boriss, Laura Miyakawa, and Jeffrey Licht.

Here is the result. It turned out that the pitch itself was an experiment for me: after fiddling around with Screenflow and iMovie for a bit, I got frustrated with their limitations and decided to just use HTML to put together the presentation.

After writing out the script for the pitch, and recording my narration with Audacity, I saved the file as both Ogg Vorbis and MP3—different browsers support different formats—and set up a directory structure.

As with Mozilla: The Big Picture, I basically stuffed everything into the structure of an HTML page. The first two slides of the presentation, for instance, look something like this:

  <div id="slides">
    <div data-at="0.0">
      <a href="http://www.mozillalabs.com"><img
         id="logo" src="images/labs-logo.png"/></a>
      <h1>Firefox-Herdict Integration Pitch</h1>
    <div data-at="4.0">
      <img src="images/server-not-found.png"/>

The data-at attribute is an example of the HTML 5 data- attribute and records how many seconds into the audio the slide should be displayed. I marked up subtitles for the presentation in a similar way.

After that, I wrote some JavaScript that just attaches a timeupdate event listener to the presentation’s audio element and synchronizes the current slide and subtitle to its position. The result is something that looks and feels to an end-user like a YouTube video—one can even “scrub” the position slider to quickly rewind and fast-forward. However, I’d argue that this approach is actually superior to standard video in a number of ways:

  1. Slides can have any valid HTML content embedded in them. Text can be copied and pasted, their look and feel can be altered through CSS; images can be hyperlinked to their original sources.
  2. It’s easier to eliminate compression artifacts without sacrificing bandwidth and download size. Text, for instance, is always super-crisp.
  3. Since everything uses HTML, CSS, and JavaScript, anyone can view-source or use a web inspector to investigate how things are put together; as I explain in The Open Web is Magic Ink, they can take it apart, see how it works, and put it back to together in a different way. Doing such things with a pure bitmapped video representation wouldn’t be possible: you’d need the source “project files” for whatever program was used to compose the video, not to mention access to said program.
  4. Subtitles can be toggled on or off, and adding new languages isn’t hard.
This approach has its downsides, too, of course: there wasn’t a really easy way for me to embed the presentation in this blog post, for instance, and it can’t be viewed at all on Internet Explorer, as far as I know.

Still, it was a fun experiment to try, and for this particular use case I actually found it easier to compose everything using Open Web technologies than with the proprietary tools at my disposal.

Please be sure to check out the actual presentation, too, as the stuff we’re doing with Herdict is way cool.

© Atul Varma 2021