Digital Cinema Distribution and Projection
How it worksDigital cinema has taken place of historical motion picture film projection. Nearly all the multiplex are using digital cinema projection technique now - a - days. Even a single screen theater like Galaxy (Rajkot ,gujrat [INDIA] ) is using the digital cinema projection....
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 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.
satellite or fibre-optic broadband.
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.
Digital Cinema Initiatives
Briefly, the specification calls for picture encoding using the ISO/IEC 15444-1 "JPEG2000" (.j2c) standard and use of the CIE XYZ color space at 12 bits per component encoded with a 2.6 gamma applied at projection. Two levels of resolution for both content and projectors are supported: 2K (2048×1080) or 2.2 MP at 24 or 48 frames per second, and 4K (4096×2160) or 8.85 MP at 24 frames per second. The specification ensures that 2K content can play on 4K projectors and vica-versa
For the sound component of the content the specification provides for up to 16 channels of uncompressed audio using the "Broadcast Wave" (.wav) format at 24 bits and 48 kHz or 96 kHz sampling.
Playback is controlled by an XML-format Composition Playlist, into an MXF-compliant file at a maximum data rate of 250 Mbit/s. Details about encryption, key management, and logging are all discussed in the specification as are the minimum specifications for the projectors employed including the color gamut, the contrast ratio and the brightness of the image. While much of the specification codifies work that had already been ongoing in the Society of Motion Picture and Television Engineers (SMPTE), the specification is important in establishing a content owner framework for the distribution and security of first-release motion picture content.
In addition to DCI's work, the National Association of Theatre Owners (NATO) released its Digital Cinema System Requirements.
The document addresses the requirements of digital cinema systems from the operational needs of the exhibitor, focusing on areas not addressed by DCI, including access for the visually impaired and hearing impaired, workflow inside the cinema, and equipment interoperability. In particular, NATO's document details requirements for the Theatre Management System (TMS), the governing software for digital cinema systems within a theatre complex, and provides direction for the development of security key management systems. As with DCI's document, NATO's document is also important to the SMPTE standards effort.
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 and Japan however, there is still a significant presence of HDTV for theatrical presentations. Agreements within the ISO standards body have led to these systems being referred to as Electronic Cinema Systems (E-Cinema).)
Digital cinema projectors
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. Because feature films in digital form are encrypted and the decryption keys are locked to the make, model and serial number of the projector used, an unapproved projector simply will not work if an attempt is made to use it to screen current release feature films from a DCP.
DLP cinema projectors
Initially DCI-compliant DLP projectors were available in 2K only, but from early 2012, when TI's 4K DLP chip went into full production, DLP projectors have been available in both 2K and 4K versions. Manufacturers of DLP-based cinema projectors are now offering 4K upgrades to many of their more recent 2K models.
Early DLP Cinema projectors, which were deployed primarily in the U.S., used limited 1280×1024 resolution or the equivalent of 1.3 MP (megapixels). Digital Projection Incorporated (DPI) designed and sold a few DLP Cinema units when TI's 2K technology first debuted but then abandoned the D-Cinema market while continuing to offer DLP-based projectors for non-cinema purposes. Although based on the same 2K TI "light engine" as those of the major players they are so rare as to be virtually unknown in the industry. They are still widely used for pre-show advertising but not usually for feature presentations.
TI's technology is based on the use of Digital Micromirror Devices (DMDs).These devices are manufactured from silicon using similar technology to that of computer memory chips. The surface of these devices is covered by a very large number of microscopic mirrors, one for each pixel, so a 2K device has about 2.2 million mirrors and a 4K device about 8.8 million. Each mirror vibrates several thousand times a second between two positions, in one light from the projector's lamp is reflected towards the screen, in the other away from it. The proportion of the time the mirror is in each position varies according to the required brightness of each pixel.
Three DMD devices are used, one for each of the primary colors. Light from the lamp, usually a Xenon similar to those used in film projectors with a power between 1 kW and 7 kW, is split by colored filters into red, green and blue beams which are directed at the appropriate DMD. The 'forward' reflected beam from the three DMMDs is then re-combined and focused by the lens onto the cinema screen.
Sony SXRD projectors
Live broadcasting to cinemasDigital cinemas can deliver live broadcasts from performances or events. For example, there are regular live broadcasts to movie theaters of Metropolitan Opera performances. In February 2009, Cinedigm screened the first live multi-region 3D broadcast through a partnership with TNT. Previous attempts have been isolated to a small number of screens. In December 2011, the series finale of the BBC dance competition series Strictly Come Dancing was broadcast live in 3D in selected cinemas.
List of digital cinema companies
- Barco — digital projector manufacturer
- Blackmagic Design — digital cinema camera and distribution equipment manufacturer
- Christie — digital projector manufacturer
- Deluxe Digital Studios — distributor and theater system integrator
- Dolby Laboratories — theater system integrator
- Doremi Labs — Digital server and theater management system manufacturer
- GDC Tech — Digital server and theater management system manufacturer
- IMAX — digital projector manufacturer
- Kinoton — manufacturer of digital projection solutions
- Kodak — theater system integrator
- NEC — digital projector manufacturer
- MasterImage 3D — 3D cinema and mobile display technology
- Panavision 3D — 3D cinema display technology
- Qube Cinema — Digital Cinema mastering, distribution and server products manufacturer
- RealD Cinema — 3D cinema display technology
- RED Digital Cinema Camera Company — digital cinema camera manufacturer
- Silicon Imaging — digital cinema camera manufacturer
- Sony — manufacturer of 4K digital projector, cinema camera manufacturer and digital cinema servers and theater system integrator
- Technicolor — distributor and theater system integrator
- Texas Instruments — developers of DLP Cinema projector technology
- UFO Moviez — world's largest satellite based Digital Cinema
- dcinex — theater system integrator & digital server manufacturer