DCI Specs - Digital Cinema Initiatives

The information, as shown in Table 4 below, is the minimum required information tosuccessfully interchange files.Data Element NameData Element DefinitionActive Horizontal Pixels (Ph) Total number of active horizontal pixels in the image containerActive Vertical Pixels (Pv) Total number of active vertical pixels in the image containerFrame RateThe rate that images are to be projected, expressed in frames per secondFrame CountThe integer number of frames in a sequenceTable 4: Required Image Structure Information3.3. Audio Specification3.3.1. Audio Concepts and RequirementsDigital Cinema audio requires standardized characteristics, channel mapping and a fileformat to successfully playback in a motion picture theater.3.3.2. Audio Characteristics3.3.2.1. IntroductionThe necessary characteristics for standardized audio are: bit depth, sample rate,reference level and channel count. These parameters are given below.3.3.2.2. Bit DepthThe bit depth shall be 24 bits per sample. DSM Audio Material having other bit depthsshall be justified to the most significant bit per [AES3-2003 Section 4.1.1].3.3.2.3. Sample RateIrrespective of the associated image frame rate, the audio sample rate shall be eitherforty-eight or ninety-six thousand samples per second per channel, commonly expressedas 48.000 or 96.000 kHz. At 24 FPS playback, there are exactly 2,000 audio samplesper frame for 48.000 kHz and exactly 4,000 audio samples per frame for 96.000 kHz. At48 FPS playback, there are exactly 1,000 audio samples per frame for 48.000 kHz andexactly 2,000 audio samples per frame for 96.000 kHz.A theater playback system shall have the capability of performing sample rateconversion as needed.3.3.2.4. Channel CountThe delivered digital audio, contained within the Digital Cinema Package (DCP), shallsupport a channel count of sixteen full-bandwidth channels.3.3.2.5. Digital Reference LevelDigital inputs and outputs shall have a nominal reference level of -20 dBFS (decibelbelow full scale) and output 85 dBc (decibels referenced to the carrier) sound pressurelevel per channel measured with pink noise.DCI Digital Cinema System Specification v.1.2 Page 30