Dynamically constructing video from bits and pieces
iPOV's Flash Virtual Playlist Control (FVPC) has two functions. The first allows easy addition and manipulation of overlays, features and enhancements onto existing videos. The second enables iPOV to dynamically assemble new videos from pieces of other videos and materials - even at the very end of the development cycle.
The playlist controller can pull in a set of Flash movies and play them in a sequence and timing that are specified in an external XML file. Everything is downloaded to the end-user's web browser where the Adobe Flash Player assembles them in the correct order and timing to play them seamlessly. In effect, the FVPC performs basic video editing each time the materials are loaded from the website. The FVPC operation is shown schematically in the following diagram.
|
Playlist Demonstrator
You can explore the playlist's dynamic power with this online demo. |
The FVPC's editing power means that iPOV can postpone the final design of a video clip until the last moment in the development cycle. In fact, we can postpone finalization until moments before the clip is downloaded to be viewed. This has two practical effects:
- By manipulating the source XML flies on a web server, different versions of the video clip can be delivered to different users. If this feature is combined with server-side logic, it would be very practical to deliver different instructional movies to different categories of users - instantly, seamlessly and transparently.
- Errors can be excised and revisions can be added very quickly - without having to reprocess all of the source video. While iPOV makes some edits directly to video using conventional video editors, it prefers to make the adjustments in the FVPC so that later corrections can be made in minutes, not days.
