Why don’t you consider the following setup:
Let the user upload the movie
Hand the movie over to Backgroundrb for processing and render a “Movie being processed”-message and a PeriodicalUpdater to your view
In the PeriodicalUpdater method, query Backgroundrb to see if the processing is finished
If it’s finished, render it in the page
This way, you’ll avoid locking up one of your mongrels during a possible long running process (and movie processing tends to be a long running process). On top of that, the user can continue working with your application while the processing is taking place. It might require you to rethink your interface a bit, but the user experience will be substantially improved.
Peter De Berdt