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digital cinema

The Digital Cinema Initiative(DCI) is developing a standard for digital cinema: D-Cinema. The DCI standard includes the complete distribution and projection technology and specifies data formats and projection techniques for D-Cinema.

The DCI Standard

The central component of the DCI standard is the Digital Cinema Package( DCP), a container that contains the image, sound and subtitle data. Due to the container format, the DCI standard can also be used for other content. Specified resolutions are 2K and 4K for the horizontal direction.

Display formats in 16:9 aspect ratio.

Display formats in 16:9 aspect ratio

The maximum resolutions are 2,048 x 1,080, which corresponds to the 2K standard, and 4,096 x 2,160 pixels, which corresponds to the 4k standard. These values are such that all image formats - widescreen film with an aspect ratio of 1.85:1, as well as Panavision and Cinemascope as widescreen with 2.35:1 - can be displayed. Widescreen is displayed at 3,006 x 2,160 pixels and Panavision at 4,096 x 1,730 pixels. HDTV with a 16:9 aspect ratio can also be displayed at 1,920 x 1,080 pixels.

Visible lines of TV pictures at different aspect ratios

Visible lines of TV pictures at different aspect ratios

A comparison with classic analog film technology shows that the resolution of the 4K standard, at eight million pixels, is twice as high as that of classic technology; the refresh rate, on the other hand, is the same for both systems at 24 Hz. From these values, an uncompressed data rate of 5.07 Gbit/s is calculated for an image resolution of 24 bits. For the compression of the image data, the Digital Cinema Initiative (DCI) has chosen Motion JPEG 2000. The data is stored in containers in Material Exchange Format( MXF).

High data rates through SMPTE

The Society of Motion Picture and Television Engineers( SMPTE) has specified the SDI interface for serial transmission of these data streams at a data rate of 2.97 Gbit/s. For audio, all 16 audio channels are stored individually and uncompressed at 24 bits in Broadcast Wave Format( BWF), which is based on Waveform Audio File(WAV). The first six channels can be used for surround sound according to 5.1, with two more Sony Dynamic Digital Sound( SDDS) can be emitted.

Special measures are dedicated to protection against unauthorized access in the DCI standard. This includes the Advanced Encryption Standard( AES), which secures data and Transport Layer Security( TLS) for data transmission.

Ultra-HDTV( UHDTV) is another cinema technology with an image resolution of 7,680 X 4,320 pixels, the 8K standard.

Englisch: digital cinema
Updated at: 18.11.2016
#Words: 384
Links: data center interconnect (DCI), standard (STD), digital, projection, data
Translations: DE

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