Pre Production Work antey enti? watch out

In film
In the film industry, pre-production formally begins once a project
has been greenlit. At this stage, finalizing preparations for
production go into effect. Financing will generally be confirmed
and many of the key elements such as principal cast, director and
cinematographer are set. By the end of pre-production, the
screenplay is hopefully finalized and satisfactory to all the
financiers and other stakeholders.
During pre-production, the script is broken down into individual
scenes and all the locations, props, cast members, costumes,
special effects and visual effects are identified. An extremely
detailed schedule is produced and arrangements are made for the
necessary elements to be available to the film-makers at the
appropriate times. Sets are constructed, the crew is hired, financial
arrangements are put in place and a start date for the beginning of
principal photography is set. At some point in pre-production
there will be a read-through of the script which is usually attended
by all cast members with speaking parts, the director, all heads of
departments, financiers, producers, and publicists.
Even though the writer may still be working on it, the screenplay
is generally page-locked and scene-numbered at the beginning of
pre-production to avoid confusion. This means that even though
additions and deletions may still be made, any particular scene will
always fall on the same page and have the same scene number.
In music
In the music industry, pre-production is a process where a
recording artist spends time creating and refining their music ideas
and producing a demo recording or rough-draft of a song in
order to establish ahead of time if the ideas are promising. This
reduces time and money wasted in expensive studios. The goal is
to enter into the major recording phase of production with the
basic and most promising ideas already established.