Abstract :
To understand
the concept of digital cinemas, we need to understand about the film based cinematography
– In a large number of cases (even today), the pictures are shot using analog
film based cameras, then converted in to digital format for editing, mixing, re-recording
and adding special effects and converted back to analog films for projecting
them through the analog film based projectors.
Digital Cinemas
use digital processes end to end – right from the capture (digital movies are
shot using digital CCD based cameras with high resolution), storage (they are stored
in digital tapes, hard disks or flash drives), processing (editing, mixing, re-recording,
sound, special effects etc are handled in the digital format), display (digital
cinema is displayed using digital projectors which are controlled by industry standard
servers with management software in the theatres) and distribution (digital cinema
copies are mostly transmitted electronically over the Internet or satellites or
even hard disks).
How Digital
Cinema Works
In addition
to the equipment already found in a film-based movie theatre a DCI-compliant digital
cinema screen requires a digital projector and a computer known as a "server" Movies are supplied
to the theatre as a digital file called a Digital Cinema Package
(DCP). For a typical feature film this file will be anywhere between 90 and 300GB
of data (roughly two to six times the information of a Blu-ray disc) and may arrive
as a physical delivery on a conventional computer hard-drive or via satellite
or fibre-optic broadband. Currently (Dec 2013) physical deliveries are most common
and have become the industry standard. Trailers arrive on a separate hard-drive
and range between 200 and 400MB in size.
Regardless
of how the DCP arrives it first needs to be copied onto the internal hard-drives
of the server, usually via a USB port, a process known as "ingesting".
DCPs can be, and in the case of feature films almost always are, encrypted. The
necessary decryption keys are supplied separately, usually as email attachments
and then "ingested" via USB. Keys are time limited and will expire after
the end of the period for which the title has been booked. They are also locked
to the hardware (server and projector) that is to screen the film, so if the theatre
wishes to move the title to another screen or extend the run a new key must be obtained
from the distributor.
The playback
of the content is controlled by the server using a "playlist". As the
name implies this is a list of all the content that is to be played as part of
the performance, the playlist will be created by a member of the theatre's staff
using proprietary software that runs on the server. In addition to listing the content
to be played the playlist also includes automation cues that allow the playlist
to control the projector, the sound system, auditorium lighting, tab curtains and
screen masking (if present) etc. The playlist can be started manually, by clicking
the "play" button on the server's monitor screen, or automatically at
pre-set times.
E-Cinema
The Society
of Motion Picture and Television Engineers (SMPTE) began work on standards for digital
cinema in 2000. It was clear by that point in time that HDTV did not provide a sufficient
technological basis for the foundation of digital cinema playback. In Europe, India
and Japan however, there is still a significant presence of HDTV for theatrical
presentations. Agreements within the ISO standards body have led to these non-compliant
systems being referred to as Electronic Cinema Systems (E-Cinema).
Digital cinema
projectors
Only four manufacturers
make DCI-approved digital cinema projectors; these are Sony, Barco, Christie
and NEC. Except for Sony, who use their own SXRD technology, all use the Digital Light Processing technology
developed by Texas Instruments (TI).
Although D-Cinema projectors are similar in principle to digital projectors used
in industry, education, and domestic 'home cinemas'
they differ in two important respects: first, they must conform to the strict performance
requirements of the DCI specification, second, they must incorporate anti-piracy
devices intended to protect the content copyright.
For these reasons all projectors
intended to be sold to theaters for screening current release movies must be approved
by the DCI before being put on sale. They now pass through a process called CTP
(Compliance Test Plan). Because feature films in digital form are encrypted and
the decryption keys (KDMs) are locked to the serial number of the server used (linking
to both the projector serial number and server is planned in the
future), a system will allow playback of a protected feature only with the required KDM.
Download :
Download :