You can play the movie in higher resolution here. from M. Roessler, http://cougar.jpl.nasa.gov/HR4796/anim.html

Here are stills from the movie with explanations of what is happening:

All stars form from clouds of gas and dust which roam our galaxy. Eventually, gravity causes the cloud to collapse; since the cloud is spinning, material falls in along the "poles" faster than it does near the "equator". This flattening results in a disk-like object.
Material slowly wends its way into the center of this disk, forming a new star. While the star continues to grow, lumps form in the disk which will ultimately become planets.
The disk eventually thins as more material falls onto the star and the protoplanets. A hole in the disk near the star forms as material is completely incorporated into the star and planets.
Now fully formed giant gaseous planets exist within the hole, even as new planets are still under construction in the outer parts of the disk. Earth-like planets will build up from the many smaller objects now in orbit close to the star.
Ultimately, the remaining dust clears completely. The final stages of building earth-like planets continue for another hundred million years or so in the form of catastrophic collisions between young bodies. After the dust settles, we have a fully formed solar system like our own.