We can consider it as the most important phase because it is where the foundations are laid for what will be done in each moment. Budgets, means, professionals to be involved, spaces or locations are defined. It is a comprehensive and realistic planning work for the entire project.
Decisions made during the pre-production phase materialize. If planning has been catastrophic, production will be a waste of time and capital in a sea of chaos. At this stage all teams work in a coordinated way (sound, lighting, audio, costumes, scenery)
The director and the filmmakers select and edit the best recorded materials. The editor is in charge of assembling and in this phase the production guarantees that everything is available to get the final product.