The romantic vision of the projectionist changing rolls of 35mm film is a thing of the past. Since the massive digital transition of the 2010s, the movies you watch are no longer physical in the traditional sense; they arrive at the projection rooms inside HDs, SSDs, via satellite, or internet, protected by encryption that expires automatically.
Currently, more than 200 thousand rooms around the world operate exclusively with digital projectors. The analogue era is over, with very few exceptions. In this article we will explore in detail this curious and complex aspect that many are unaware of.
The end of the film (with rare exceptions)
Many people may still believe that feature films arrive in theaters on those giant 35mm metal reels spinning on noisy projectors, but no. Since the massive digital transition of the 2010s, more than 200,000 rooms around the world operate exclusively with digital projectors. The only notable exception are the very few cinemas IMAX remaining analogues (fewer than 30 globally), which still use 15-perforation 70mm film — a format that offers resolution equivalent to 12-18K, technically superior to 4K digital IMAX.
The loading of an IMAX film into the projector
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Christopher Nolan is one of the last staunch defenders of the purely analogue format. When it launched Oppenheimer in 2023, the director printed IMAX 70mm copies that measured approximately 17km of unrolled film and weighed around 290kg each. The technical challenge is brutal: the film needs to move quickly through the projector, but stop momentarily 24 times per second at the projection gate without tearing.
To prevent the film’s own weight from creating enough tension to tear it apart, the IMAX system uses dozens of distribution rollers that isolate different sections — loops and extra lengths act as shock absorbers that absorb sudden movements. The projector lamp is so powerful that it would literally burn the film if it remained still for more than 1 second, so the airflow created by the film’s extended path constantly dissipates heat.
Rooms like TCL Chinese Theatre IMAX in Los Angeles, the Cinesphere in Toronto and the BFI IMAX in London they still maintain operational 70mm projectors for special releases.
In Brazil, the first IMAX arrived in 2006 at Shopping Bourbon in São Paulo, opened with the documentary 3D Seabed. However, all Brazilian IMAX theaters, including those at UCI Kinoplex in Recife, Fortaleza and Rio de Janeiro, in addition to Cinesystem Bourbon, have operated exclusively in digital format since the complete transition in the 2010s. No 70mm analog theater has ever been installed in the country.
For 99.9% of current releases, digital DCP has completely replaced this analog infrastructure.
What is a DCP (and why it is complex)
The Digital Cinema Package is not a simple video file. It is a structured collection of MXF (Material Exchange Format) files that store video, audio and subtitles separately, tied together by XML metadata. The image uses the XYZ color space (not common monitor RGB), optimized for the huge range of cinema projectors, while gamma 2.6 compensates for the reduced luminance of dark rooms. This modular separation allows a single DCP to contain multiple versions: audio in 10 languages, subtitles in 15 languages, 5.1 or Atmos mixes, all reusing the same image track.
Encoding each frame in JPEG 2000 (industry standard) consumes hours of processing even on powerful machines, transforming a 90-minute film into 100-300GB of data. This process explains why professional labs charge between $10-$15 per minute of film: it’s not just conversion, but rigorous technical validation following SMPTE/Interop standards to ensure global compatibility.
The encryption
Here comes the most ingenious (and restrictive) system of digital distribution: the KDM (Key Delivery Message). Each cinema server has a unique cryptographic certificate, like an electronic fingerprint. When a distributor authorizes the screening of a film, it generates a specific KDM for that projector, valid for a specified period — generally 1 to 4 weeks. Without this key, the DCP remains encrypted and unusable, even if the theater has the complete file on the HD.
This architecture solves two problems simultaneously: it prevents piracy (since the KDM automatically expires after the screening window) and guarantees territorial control (the same KDM does not work in other cinemas). An interesting practical example, which serves as an example, is Top Gun: Maverick. When the film reached its 20th week in theaters, Paramount could make KDMs flexible for isolated afternoon sessions, but newly released films had renewable 7-day KDMs, forcing cinemas to negotiate each extension.
How does the film reach the theater?
HDs
The traditional method uses external hard drives formatted in ext3 Linux with inode 128 — an archaic technical requirement, but mandatory for compatibility with old servers running outdated Linux kernels. USB 3.0 drives are the current standard.
DCP PACKED
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IMAX has moved to SSDs (more expensive but 3-4x faster transfer), especially for 4K DCPs exceeding 400GB. After the film is released, the distributor usually requests the units to be returned.
Satellite
In Brazil and Latin America, the CinecolorSat has operated the region’s largest satellite distribution network since 2013, connecting more than 1,700 cinema complexes. The system works from a NOC (Network Operations Center) located in Santiago, Chile, which transmits DCPs via multicast directly to servers installed in each cinema. This means that a single DCP upload is simultaneously received by hundreds of rooms, eliminating shipping costs and reducing lead times from 3-5 days (land logistics with HDs) to 6-12 hours of overnight download.
The NOC monitors the status of each server in real time: available storage space, condition of the receiving equipment (Hughes antennas) and content access permissions as authorized by distributors. This infrastructure is vital for simultaneous global releases of blockbusters, where 500+ theaters need to receive the same 250GB DCP on the same night — something impossible to coordinate with physical HD logistics. CinecolorSat also maintains interconnected offices in Mexico, Brazil, Colombia, Peru, Argentina and Chile, allowing a file sent from São Paulo to be retransmitted via satellite throughout Latin America without the need for duplicate uploads.
Internet
Distribution via the internet is the fastest growing, although it still faces infrastructure challenges. Specialist platforms such as DCU Connect (Digital Cinema United), Movie Transit (Unique Digital in partnership with Deluxe Technicolor) and onlinedcp in Germany offer proprietary DCP delivery networks via broadband. DCU Connect, for example, is free software for exhibitors that installs in 10 minutes on the cinema server and allows direct downloads of securely encrypted DCPs.
In the United States, the DCDC (Digital Cinema Distribution Coalition), a consortium formed by Warner Bros., Universal, AMC Theaters and Regal, controls the digital distribution of most major studio releases via satellite and internet simultaneously. In Brazil, in addition to CinecolorSat, laboratories such as Gaia Digital and international platforms such as DCPShare and PureDCP offer upload of DCPs to the cloud with direct download links for festivals and independent exhibitions.
How big are the files?
When we talk about DCP, the storage numbers are impressive. A typical 90-minute movie in 2K (2048×1080 pixels) takes up between 150-200GB, while the 4K version (4096×2160 pixels) jumps to 250-300GB. This happens because each frame is individually compressed in JPEG 2000 with a maximum bitrate of 250Mbps — a DCI standard that guarantees cinematic quality, but results in massive files.
Oppenheimer by Christopher Nolan is a documented extreme case: the 1.90:1 4K digital IMAX version weighed exactly 485GB for 3 hours and 1 minute of film, resulting in a bitrate of approximately 46MB/s. The conventional flat (1.85:1) and scope (2.39:1) versions were between 313-318 GB each, with variations depending on the language of the audio track. The Dolby Vision version with Atmos track occupies around 314 GB.
But the absolute record holder is Avatar: Fire and Ashes, whose full DCP at high frame rate (48fps) and 3D surpasses 600GB. Disney had to produce more than 1,000 different versions of the film — combining 2D/3D, different screen formats (flat/cinemascope), 24fps/48fps, multiple brightness levels for 3D projection and different languages. To manage this insane logistics, the distributor created a global search system where each theater reports exactly which screen and projector configuration it has, receiving only the specific DCP needed, not all variants.
2K still dominates projection
Despite the hype about 4K, the overwhelming majority of cinemas in the world still use 2K projectors. Even festivals showing in IMAX often request 2K DCPs. The reason is practical: 4K doubles file size, increases production costs and encoding time, with no noticeable visual gain for the majority of audiences sitting at normal distances from the screen.
However, 4K technology is expanding in premium cinemas. Manufacturers like Christie Digital offer full lines of 4K laser projectors, including the Christie CP4450-RGB (50,000 lumens) and the Christie Eclipse.
A Barco competes with models like the Smart Laser 4K, while the Sony dominates digital IMAX theaters with dual 4K projectors that deliver a combined 60,000 lumens. Premium networks such as Cinemark XD, AMC Dolby Cinema and digital IMAX theaters globally have been operating mostly in native 4K since 2020.
The invisible ecosystem behind the session
When you buy a ticket to watch that long-awaited film, a silent logistical dance has already taken place weeks before: the studio generated hundreds of versions of the DCP, laboratories duplicated thousands of HDs or scheduled satellite uploads, and cinema servers received KDMs valid for exactly 7 days. The HD that the employee connects to the projector carries encrypted data that only works on that specific equipment, that specific week. After the last session, it goes back to the distributor, is reformatted and reused in the next release
This transition from analog to digital eliminated 35mm reels, but created an unprecedented control system: distributors can remotely end the screening of any film just by not renewing KDM.
And when a classic returns to theaters in 4K, or gets a Blu-Ray re-release, the process is even more fascinating, involving scanners capable of capturing every grain of the original film. Understand in this other article of ours how is it possible for a very old film to be released in 4K.
Source: https://www.hardware.com.br/artigos/como-filmes-chegam-cinema/
