Small Guide on Cinema Tech
Here's Some Basic Things to Know:
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Types of Modern Movie Theatre Systems:
1. Digital Theatres:
- Standard 2D Projection Theatre
- 3D Projection Theatres
- Dolby Theatres
- IMAX Digital Theatres (Liemax)
- IMAX 3D Theatres
- HFR Theatres
- HFR 3D Theatres
2. Film Theatres:
- 35mm Film Theatre
- 70mm Film Theatre
- IMAX 70mm Film Theatre (15/70)
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1. Digital Theatres:
Here is some common information related to all types of digital cinema:
Resolution: 2K or 4K
Video Compression Codec: JPEG 2000
Audio/Video File Container: MXF (.mxf)
Color Space: DCI P3, mapped to XYZ
Audio Compression: Uncompressed PCM Multichannel Wav
Audio Bit depth: 24Bit
Audio Sample Rate: 48/96kHz
Aspect Ratio:
- Scope (2048 × 858 or 4096 × 1716) = 2.39:1 aspect ratio (Widely used for all new movies)
- Flat (1998 × 1080 or 3996 × 2160), = 1.85:1 aspect ratio
- HDTV (1920 × 1080 or 3840 × 2160) 16:9 aspect ratio (~1.78:1)
- Full (2048 × 1080 or 4096 × 2160) (~1.9:1 aspect ratio, official name by DCI is Full Container. Not widely accepted in cinemas.)
In addition to the equipment already found in a film-based movie theatre (e.g., a sound reinforcement system, screen, etc.), a DCI-compliant digital cinema requires a digital projector and a powerful computer known as a "server".
This ia Christie Pandoras Box Server. It combines the full feature software set with the flexibility and reliability of a powerful hardware platform designed for maximum creative results.
Pandora's Box has:
- XEON processor
- SSD RAID system
- Nvidia Quadro GPUs
- Up to 8 DisplayPort outputs
- Optional sync board
Different Server Models for Different Perfomance Demands:
- PK1 960GB SSD / 24GB RAM storage with XEON processor
- PK2 7.5 TB SSD / 48GB RAM storage with XEON processor
- PK3 32TB SSD / 48GB RAM storage with XEON processor
All servers feature SSD storage and the latest hardware components for maximum stability and performance. All servers include dual Intel XEON processors.
Here is a List of Different Brand Digital Cinema Servers/Players & OS used by them:
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 GB and 300 GB 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 Internet. Promotional trailers arrive on a separate hard drive and range between 200 GB and 400 GB in size. The contents of the hard drives may be encrypted.
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, to prevent illegal copying and piracy. The necessary decryption keys are supplied separately, usually as email attachments and then "ingested" via USB.
What is a KDM?
A KDM (Key Delivery Message)is a small file generated by content mastering facilities (like Deluxe Technicolor Digital Cinema for example) and then sent to cinemas to unlock their content for playback. They have been around since 2006 in one form or another, and are currently in a format called 'SMPTE Modified Transitional 1'.
Why use KDM?
Film studios go to great lengths to prevent the creation of unlicensed versions of their content and also want to ensure that cinemas are upholding their screening agreements. In light of the threat of digital piracy, when studios send digital content to cinemas, they encrypt it as a DCP (Digital Cinema Package) so that it could only be played exactly where they wanted it to be. KDM’s were created to decrypt these DCPs for playback of one specific piece of content at one screen over a pre-determined period of time.
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.
Several versions of the same feature can be sent together. The original version (OV) is used as the basis of all the other playback options. Version files (VF) may have a different sound format (e.g. 7.1 as opposed to 5.1 surround sound) or subtitles. 2D and 3D versions are often distributed on the same hard drive.
This is a screenshot of 2K DCP of Candlestick (2014), a 1h23m movie. which includes a Uncompressed 5.1 PCM Wav audio.
The file structure of a DCP is organized into a number of Material eXchange Format (MXF) files that store audio and video streams, and auxiliary index files in XML format that tell the digital server how to display the movie.
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 Projectors:
For More Projector Models: https://www.christiedigital.com/products/cinema/projection/
You Can See List of DCP Players (Softwares) Here:
https://en.m.wikipedia.org/wiki/Digital_Cinema_Package
Guide for Making a DCP:
https://www.knuterikevensen.com/
Free Software Tool for Creating a DCP:
http://code.google.com/p/opendcp
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● Standard 2D Theatre
Video Bitrate: Variable bitrate of 75-125 Mbps for 2K & 100-200 Mbps for 4K Resolution (max. 250Mbps)
NOTE: Regardless of Resolution, there is no fix bitrate numbers for DCP J2K Video, Different distributor studios encode DCP at different bitrates (under 250Mb/s) except for IMAX 4K 3D DCP which is encoded at under 500Mb/s
Framerate: 24fps
Audio Codec: Uncompressed 24bit PCM Wav 48kHz
Audio Channels: Channels depends on how many sound channels movie is mastered into, it can be 2.0, 5.1 or 7.1
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● 3D Projection Theatres
Video Bitrate: 250 Mbit/s - a net 125 Mbit/s for single frame
Resolution: 2048× 1080 (2K)
for Scope (2.39:1) presentation 2048×858 pixels of the imager is used
for Flat (1.85:1) presentation 1998×1080 pixels of the imager is used
Framerate: at 48 frame/s (24 frame/s per eye)
Audio Codec: Uncompressed 24bit PCM Wav 48kHz
Audio Channels: 5.1 or 7.1
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● Dolby Theatres
Video Bitrate: Variable bitrate of 75-125 Mbps for 2K & 100-200 Mbps for 4K Resolution (max. 250mb/s)
Framerate: 24fps
Audio Codec: Uncompressed 24bit Dolby TrueHD Atmos 48/96kHz (Object Based Sound)
Audio Channels: 5.1 or 7.1
Image Quality: We get to see 500 times the contrast ratio compared to a standard movie projection system, pure black levels, an expanded color gamut and twice the brightness.
Projector: Dolby Vision uses dual 4K Laser Projectors designed in partnership with Christie to support films that have been optimized and color graded for Dolby Vision HDR.
Sound of Dolby Theatres:
Dolby Atmos creates powerful, moving audio by introducing two important concepts to cinema sound: audio objects and overhead speakers.
Sound comes from all directions, including overhead, to fill the cinema with astonishing clarity, richness, detail, and depth.
In Dolby Atmos, by contrast, sound can be freed from channels. It enables artists to treat specific sounds as individual entities, called audio objects. These can be precisely placed and moved by the soundtrack creator anywhere in the cinema's three-dimensional space, though the artist can continue to use channel capabilities as desired. The Dolby Atmos cinema processor then determines which of a cinema's huge array of front, back, side, and overhead speakers it will use to recreate this lifelike movement.
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● IMAX Digital Projection Theatres (LieMax)
Video Bitrate: Variable bitrate of 75-125 Mbps for 2K & 100-200 Mbps for 4K Resolution (max. 500mb/s)
Framerate: 24fps
Audio Codec: Uncompressed 24bit PCM Wav 48kHz
Audio Channels: 6 Track or 12 Track (extremely few IMAX-branded theaters have the 12-channel sound system. The 12-channel sound system is found exclusively in IMAX with Laser theaters. Those theaters have the very expensive 4K resolution dual laser projection setup.)
NOTE: IMAX 6 Track sound has different Channels layout than conventional 5.1 Systems. IMAX movie soundtrack goes through a special process, the sound team at IMAX goes back to the stems, the original tracks from the movie & works with filmmakers to create a unique soundtrack.
Projectors: IMAX Xenon Digital uses dual 2K (2048 x 1080) Barco xenon-bulb projectors. IMAX Laser uses dual 4K (4096 x 2160) Barco laser projectors.
Server: Doremi servers with dual SDI output.
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● IMAX 3D Theatres
Variable bitrate of 75-125 Mbps for 2K & 200-500 Mbps for 4K Resolution (Max. 500Mbps)
Note: Only IMAX 3D Theatres can show 3D at 4K UHD Resolution, other 3D theatres only have 2K Resolution
Framerate: at 48 frame/s (24 frame/s per eye)
Audio Codec: Uncompressed 24bit PCM Wav 48kHz
Audio Channels: IMAX 6 Track (5.1)
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● HFR (High FrameRate) Theatres
Video Bitrate: Variable bitrate of 75-450 Mbps for 2K (Max. 450Mbps)
Note: All HFR Movie Presentation in theatres are at 2K Resolution, No Theatres show more than 24fps on 4K
Framerate: 24fps, 48fps, 60fps, 120fps etc
Audio Codec: Uncompressed 24bit PCM Wav 48kHz
Audio Channels: 5.1 or 7.1
Here you can see List of HFR Presented movies till date:
https://en.m.wikipedia.org/wiki/List_of_films_with_high_frame_rates
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● HFR 3D Theatres
Video Bitrate: Variable bitrate of 75-450 Mbps (2K)
Framerate: 24fps, 48fps, 60fps, 120fps etc
Audio Codec: Uncompressed 24bit PCM Wav 48kHz
Audio Channels: 5.1 or 7.1
Only 5 Movies are released for HFR 3D Presentation:
1. The Hobbit: An Unexpected Journey (2012) 48FPS 3D 2K
2. The Hobbit: The Desolation of Smaug (2013) 48FPS 3D 2K
3. The Hobbit: The Battle of the Five Armies (2014) 48FPS 3D 2K
4. Billy Lynn's Long Halftime Walk (2016) 120FPS 3D 2K
5. Gemini Man (2019) 120FPS 3D 2K
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2. Film Theatres:
Here is some common information related to all types of film cinema:
Resolution of Films: It is estimated that 35mm film has a digital resolution equivalent to 4K, 35mm Imax film equates to 6K, while 70mm Imax is closer to 12K. Regardless of how they are shot, most films will be converted into a digital format for editing, colour grading and VFX (called digital intermediate and usually at 2K resolution). While some films are scaled back up to a digital or film print for distribution, even Imax digital projection systems are not capable of playing back higher than 4K.
Sound on Films: is a class of sound film processes where the sound accompanying a picture is recorded onto photographic film, usually, but not always, the same strip of film carrying the picture. Sound-on-film processes can either record an analog sound track or digital sound track, and may record the signal either optically or magnetically. Earlier technologies were sound-on-film, meaning the film's soundtrack would be on a separate phonograph record.
Digital Sound for Films: Sound data is stored on separate compact discs/Hard disk synchronized by a timecode track on the film just to the right of the analog soundtrack and left of the frame.
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● 35mm Film Theatre
Framerate: 24fps
Digital Sound: 3 different digital soundtrack systems for 35 mm cinema release prints were introduced during the 1990s. They are: Dolby Digital, which is stored between the perforations on the sound side; SDDS, stored in two redundant strips along the outside edges (beyond the perforations); and DTS, in which sound data is stored on separate compact synchronized by a timecode track on the film just to the right of the analog soundtrack and left of the frame
Audio Codec:
1. ATRAC (for SDDS) 44.1kHZ (Max. 2.2Mb/s Bitrate)
2. AC-3 (Dolby Digital) 48kHz (Max. 640Kbits/s Bitrate)
3. DTS 48kHz (Max. 1509Kbits/s)
Audio Channels:
1. 8 Channels (7.1) for SDDS
2. 5.1 Channels for Dolby Digital (AC-3)
3. 5.1 Channels for DTS
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● 70mm Film Theatre
As used in cameras, the film is 65 mm (2.6 in) wide. For projection, the original 65 mm film is printed on 70 mm (2.8 in) film. The additional 5 mm are for four magnetic strips holding six tracks of stereophonic sound.
Although later 70 mm prints use digital sound encoding, the vast majority of existing and surviving 70 mm prints predate this technology.
The DTS digital sound-on-disc system was adapted for use with 70 mm film, thus saving the significant costs of magnetic striping.
Each frame is five perforations tall, with an aspect ratio of 2.2:1
Framerate: 24fps
Audio Codec: DTS 48kHz (max. 1509Kbits/s Bitrate)
Audio Channels: 5.1
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● IMAX 70mm Film Theatres (15/70)
Framerate: 24fps
Audio Codec: Uncompressed 24bit PCM Wav 48kHz (Digital Sound)
Audio Channels: 6 Track (5.1)
Aspect Ratio: 1:44:1
Projectors: IMAX 70mm Projectors use Single Xenon Bulb based Projector
There are four types of projectors used in IMAX, namely GT (Grant theater), GT 3D (duel rotor), SR (small rotor) and MPX . All these projectors use the 70mm format.
How Sound Works: IMAX 70mm nowadays uses a hard drive that carries a single uncompressed audio file that contains the six channels. These are converted directly to analogue rather than processed through a decoding method such as DTS. it is locked to the projector by a SMPTE time code system synchronization apparatus.
Like conventional theatres, IMAX theatres place speakers both directly behind the acoustically-transparent screen, and around the theatre to create a "surround sound" effect. IMAX also provides a "top center" speaker in addition to the centre speaker found in conventional theatres. This extra channel allows the sound mix engineers to take advantage of the screen's greater height.
More about IMAX Presentation: https://www.slideshare.net/Sebby23/imax-presentation
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As said earlier, DCP J2K Video has Variable bitrate & Different Distributors set different Video Bitrate for their Movie DCP (Under 250Mbps). Here is small List of Different Movie Version Sizes to get More insight:
Distributed by: 20th Century Studios
Avatar (2009) 2D 2K (2h 41m french release) = 186GB
Avatar (2009) 3D 2K (2h 41m us release) = 276GB
Distributed by: Warner Bros. Pictures
The Hangover Part III (2013) 2D 2K (1h 40m us release) = 105.8GB
The Hobbit - An Unexpected Journey (2012) IMAX 3D HFR@48fps (2h 49m us release) = 457GB
The Hobbit - An Unexpected Journey (2012) 2D 2K 24fps (2h 49m us release) = 200GB
The Hobbit - An Unexpected Journey (2012) 3D 2K 24fps (2h 49m us release) = 250GB
Distributed by: Walt Disney Studios Motion Pictures
Avengers Endgame (2019) 2D 2K (3h 2m us release) = 223Gb
Avengers Endgame (2019) 3D 2K (3h 2m us release) = 237Gb
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Note: All the Info is gathered from different internet sources, you can search topics on internet for more info & insight.