Why IT Skills Are Essential for Projectionists
Back in the days of 35mm film prints, cinema projectionists would patrol projection booths during a showing to monitor the rollers guiding the film to the projector like track wheels on a train. They would pay attention to abnormal sounds; were they squeaking? Did they need lubrication? As the film fed to the projector from the rotating platters and back again, the projectionist would make sure the platter speeds were normal. If the light on the screen flickered, this would let the projectionist know that the xenon bulb needed changing. But in today’s digital projection suites, the art of film projection is less about the foibles of celluloid and more about servers, switches, and stable connections. We will provide some set up guidelines (further below) and scenarios in this article to help maintain and troubleshoot issues that can arise in a digital projection suite.

Understanding digital cinema networks is no longer optional for projectionists, cinema technicians and managers of today, it’s essential. From ingesting digital cinema packages (DCPs) into playback systems to troubleshooting failed content transfers, information technology (IT) literacy keeps the booth running smoothly and, more importantly, keeps the audience blissfully unaware of the chaos that sometimes unfolds behind the scenes.

Understanding the Digital Cinema Network
A theatre management system (TMS) is the control centre of most multiplexes, managing content across all screens. Paired with or integrated into a library media server (LMS), it stores and distributes DCPs to each auditorium’s server or secure media block. Single screen and smaller cinemas tend to use a lighter variant of a TMS, working without LMS storage, to schedule shows, leaving the content to be stored on each of the screens servers.

These media blocks connect to projectors and audio processors, sending automation commands to turn the projector light on, cue the sound track and fade the lights in the auditorium. The key delivery messages (KDMs) ensure only authorised projection equipment at specific theatre sites can play the encrypted content within a predefined time frame. 

Early digital projection suites typically relied on external media servers, which communicate securely with projectors and audio processors. These servers also issued automation commands to switch on the projector lamp, cue the soundtrack, and fade the lights in the auditorium.

Advancements in projection technology now enable manufacturers to offer fully integrated solutions within the projector chassis itself. These integrated units consolidate the functions of a media server (including the media block or media player) and, in some instances, the audio processing hardware, thereby eliminating the need for separate external servers or dedicated audio processors. |

A TMS can route KDMs to the appropriate projection equipment within a cinema. This entire system is connected, via Category 5 (CAT5) cables to a series of network switches, typically using a star topology in multiplexes or direct connections in smaller venues.

Knowledge of these systems is crucial for the modern projectionist. 

Setting Up and Securing the Network
DCPs are data-heavy, a 90-minute 2K resolution feature with 5.1 audio, subtitles and audio description can total just over 100 gigabytes (GB). Throw in 4K resolution, 7.1 audio, advanced object based audio like Dolby Atmos or DTSx, then the storage could double in size. That’s why fibre or gigabit ethernet connections are recommended between the TMS and screen servers. It is best practice to avoid wireless content transfers all together.

To ensure stability:

• Assign static IP addresses to each device (projection equipment) to avoid address conflicts.
• Use RAID arrays for storage redundancy. The data is stored across an array of hard disk drives (HDDs), so should one fail, the data is safe across the remaining drives.
• Install backup switches for network resilience.

And with the increasing risk of cyber attacks, security matters. Virtual private networks (VPNs) are standard for secure remote access to a digital cinema network from outside a theatre location. As well, technical support teams will have access to the latest software patches and firmware, keeping the equipment up to date. Cinemas can further beef up their cybersecurity by only allowing trained staff to have access to their programming and network systems  to protect content from tampering or theft.

Troubleshooting: When the Network Fails You
Despite using top-of-the-range operations technology, cinemas are not immune to IT problems and things can still – and will – go wrong. The difference between a picture perfect presentation and a black screen can be one dodgy cable. Let’s break down some of the common issues that plague projection booths and share some insights into fixing them.

1. Server Missing From TMS
The auditorium is full of school children, the show is about to begin and the server has vanished from the network. It’s easy for anxiety to creep in but try to stay calm. Most connectivity issues have straight forward fixes.

Start with the physical layer:

• Check if the network switch port light is blinking.
• Reset the ethernet cable on both ends.
• Replace questionable cables (especially if the port’s link speed drops unexpectedly).

If the server still won’t appear:

• Confirm that all devices share the same subnet mask and have unique IP addresses.
• Watch for IP address conflicts (two devices fighting for the same IP = flickering visibility).
• Try pinging the server from the TMS.

If all else fails, do a systematic reboot. Shut down the TMS from the software, then switch it off at the mains. Follow the same procedure for all the servers, then boot them all back up again. After this, power up the TMS.

2. The DCP That Wouldn’t Ingest
The DCP for that highly anticipated blockbuster movie has arrived. You’ve plugged it into the TMS and have started the ingest process. However, halfway through the transfer, the gremlins and errors pop up cancelling the ingest. DCP ingestion failures can raise blood pressure, but understanding the typical causes, helps to tackle them calmly.

Common causes:

• Incompatible file system: DCP drives may use EXT2/3, NTFS, or FAT32. Servers often don’t read exFAT or macOS HFS+.
• Corrupted files: try copying the DCP to another drive and re-ingest. If the same file fails repeatedly, it’s likely corrupt.
• Low server storage: always try to keep server storage under 85% full for stability.
• Loose USB connections or flaky drives: try another ingest method.

When ingesting over the network, slow speeds or dropouts point to network instability. If USB direct ingest works but TMS network transfer doesn’t, your network is the culprit.

And sometimes… just reboot the server. It works more often than you’d expect.

3. KDM Headaches
The DCP has been successfully transferred to the server, the playlist has been checked with all the preshow adverts and trailers, however, the TMS is now displaying the gut wrenching red warning, “KDM not valid” message. That feature presentation your audience is excited to see is blocked. KDMs are tiny XML files that can make or break a screening. So it’s imperative to check:

• That the KDM matches the correct media block certificate.
• That the server’s clock is correct – KDMs are time-sensitive.
• That the KDM was ingested to the right server.

TMS systems often handle this automatically, alerting you if a KDM is missing, valid or expired for the media block serial number. But if you’re doing it manually, it’s easy to misplace a key. Keep a list of media block serial numbers and double-check filenames.

If you’re still stuck, call your film buyer, distributor or integrator. They can usually issue a new key quickly if you have the server ID and screening details handy.

4. Network Speeds
Ever seen a 110GB DCP crawl across the network like it’s stuck in molasses? It’s before the school holidays, and the cinema has had four DCPs delivered, with transfers all set to proceed overnight. However, in the morning, the TMS cancelled three of the content transfers with the first having only completed 1%. Bandwidth issues are often caused by:

• Old or faulty cables (e.g. a bad Cat5e cable throttling speeds to 100Mbps).
• Outdated switches that can’t handle gigabit speeds.
• Overloaded networks, especially if the booth shares bandwidth with public Wi-Fi or office internet.

Tips:

• Stagger transfers to avoid flooding the network.
• Use dedicated switches or VLANs for projection traffic.
• Monitor your switches’ admin panels for errors, port speeds, and uptime.
• Have a dedicated network for the Digital Cinema Suite.

When all else fails, cut out the TMS completely and plug the drive straight into the auditorium server. Direct ingest skips the network entirely and can save the day.

A Multi-Functional Role
Projection booths may have swapped splicers, reels and platters for patch cables, hard disk drives and network switches but the mission’s the same: the show must go on (as smoothly as possible).

Digital projection demands a new kind of projectionist, part technician, part troubleshooter, part detective. Understanding how your cinema network works right down to subnet masks and blinking port lights gives you the power to resolve issues swiftly and confidently.

There is no greater satisfaction than seeing the auditorium lights fade, the audio processor cue over to play the DCP soundtrack and the fans on the projector fire up, knowing that the audience is enjoying the magic, blissfully unaware of the cable you just replugged seconds before showtime.