5 Reasons to Avoid “Do It Yourself DCPs”


Since I started SDC in 2009 I’ve always feared that film makers would stop outsourcing the creation of DCPs to labs like ours and instead use DIY methods to manage the process themselves. There is plenty of hacky software freely available and plenty of instructional guides and blogs on how to use it. But ten years later and the DIY method still hasn’t caught on. Fortunately, D-Cinema labs are still busy. Why? Because homemade DCPs suck! Here are my top five reasons why:

1 – Quality and Reliability

I love cinema and I think the DCP should be the ultimate distributable version of the film in terms of technical quality. Just like the 35mm print used to be. Labs create DCPs on super high-end equipment such as Clipster by Rohde and Schwarz costing upwards of 80k. They’re then QCd in highly calibrated test cinemas to give the film makers or distributors a true idea of how the film will look in a standard commercial digital theatre. (Make sure your lab has a proper calibrated test cinema and offer you a QC session. If they don’t, avoid them like the plague.) Not only does a properly made DCP look completely faithful to the original film, but the DCP itself will work in any DCP capable cinema on the planet. DCPs made on hacky Internet tools are often not reliable and will fail to ingest.

When people try to do this process themselves, they put about as much effort in as a YouTube upload. They don’t check the DCP because they don’t have a cinema, and the first time they see it is in front of 300 people at a film festival. And, low and behold, if the thing even plays, the colours look completely wrong. That’s because making DCPs involves a big colour-space conversion. In most cases we’re mapping REC709 to P3 and then describing that P3 in terms of XYZ colour values that a Xenon lamp projector is designed to work with. It involves understanding lots of tricky colour space things. Such as whether the picture is full range or legal SMPTE range and handling that correctly so the colours don’t look crushed or washed out. It means understanding the difference between the thousands of NITs produced by a TV compared to the 14ft lamberts produced by a DCI compliant projector and interpreting that difference correctly. Sometimes it involves working with more exotic colour spaces like REC2020. Or old 10bit DPX log files from 35mm film scans. In other words, the process is complicated and requires knowledge and skill to get right. If you don’t posses that knowledge and skill, you should not attempt making DCPs with software dowloaded for free from the Internet. If you’re interested in digital cinema mastering, go and work for a digital cinema lab and learn how to do it properly. Reading this book cover to cover is an essential starting point.

If you’re serious about DCPs, this book is a brilliant starting point.

2 – The Standard isn’t the Standard

There are various unwritten rules in digital cinema mastering that only encoders know. If you’re trying to make your own DCP, you’re probably following a blog or online guide not written by an experienced encoder. Or you might be looking things up in the DCI specifications. But there are grey areas. For instance, a large proportion of the world still uses the older Interop DCP specification. There are still cinemas that can’t play 25fps. Very few cinemas have their masking set up for the so-called “container” format that uses the entire chip (2048 x 1080). Some digital cinema servers freak out if you ingest from an EXT2 drive with a 256bit inode. I could go on forever. Labs know about these subtleties through years of experience. And we’re still learning things today. Which leads us onto…

3 – Support When It All Goes Wrong

Things go wrong with DCPs all the time. And when they do, you want an experienced voice at the end of the phone who can solve everything in a jiffy. A good lab will always provide you with support even at odd hours. Technicians have seen it all before, and when something new crops up, they know how to escalate the issue and get it fixed.

I have a close friend who is a big-shot IT guy for one of the tech giants. He’s really good at tech support and I often pester him for help with computer issues. He’s good for all the obvious reasons. He’s an expert, he cares a great deal about what he does, he enjoys helping people. But there is something else as well. Great technicians don’t get distracted by red herrings. When fixing an issue they instinctively know where the problem lies before they know what the solution is. They don’t work to a flow chart like somebody in a call centre. Instead, they get hunches on things that lead them in the right direction.

Often a DCP is the final link in the chain after years of work and millions invested. And perhaps it’s the night of a big glitzy premiere. Failure is not an option at these screenings. It amuses me that that all of that work can come to rely on a single flimsy USB port on an old server. That’s why you need great technicians behind you. They will fix things when it all, inevitably, goes wrong.

4 – Security is Important

DCPs can be encrypted to protect them from unauthorised playback and transcoding. If a DCP is encrypted, you need a lab to look after the complex decryption process. Your lab will have a Trusted Device List (TDL). This is a database that holds the public certificates for every single cinema screen everywhere. They will have a highly automated way of sending decryption keys to cinemas via email in the form of Key Delivery Messages (KDMs). Each KDM is encrypted and can only be opened by the cinema server it’s targeted to. The process is tricky, often goes wrong due to out of date information and requires round-the-clock technical support. The vast majority of cinemas are very easy to work with. But, sadly, you often encounter poorly trained cinema staff who have no idea how the process works. It can be a nightmare. It’s virtually impossible to manage an encrypted DCP without the help of an experienced lab.

But why encrypt? A lot of folks don’t realise just how easy it is to convert a DCP into other formats. If a DCP isn’t encrypted then anyone can do whatever they like with it. For a high value film, encryption is a no-brainer. But, when you think about it, encryption is important for all DCPs. A lot of first time film makers who are trying to get exposure will respond to this with “hey, I’d be flattered if my film was being pirated and distributed all over the Internet. I want as many people as possible to watch it!” The problem is that people don’t necessarily transcode DCPs for criminal reasons. They often do it because, frankly, they’re idiots. We’ve seen projectionists with broken down equipment converting DCPs into crappy looking DVDs in order to save their screening and not have to refund tickets. We’ve seen film festivals converting people’s DCPs, without permission, into low quality QuickTimes and sharing them online to promote their event. Or creating promo stills from them but not doing the colour space conversion correctly and they end up looking completely wrong. We’ve also seen cases of poorly made DCPs that fail to ingest and the festival or the cinema, who don’t know what they’re doing, try to encode a new DCP from the old DCP and it ends up all kinds of wrong.

That’s why security is important. It’s not just there to protect from piracy, it’s there to keep you in control of your asset. I always recommend encryption. It makes very little difference to budget and a world of difference to the security and integrity of the DCP.

5 – Respect For Departments

Even though we work in the latest stages of post production we still consider what we do an important step in the film-making process. And in the collaborative world of film-making, it’s important to have respect for all departments because it keeps the industry healthy and flourishing. Departments should not interfere with each other. DOPs don’t swing booms, sound recordists don’t do makeup, VFX artists don’t direct and producers never make tea. So don’t let your editor or grader make the DCP because they’re not the experts in that process. Let us do what we do best and you will be rewarded with a perfectly produced and reliable DCP that looks fantastic and will play anywhere in the world. And expert support and guidance throughout the process.

Having said all this, sometimes you’re on a shoe-string budget and you simply can’t afford the luxury of a D-Cinema lab. To folks in this position I would recommend the following:

Get a quote and barter as best you can. It may work out cheaper than you think. But avoid dodgy bedroom setups. The golden rule is, no test cinema = not a proper DCP lab.

Call up the big labs and see if they have a trainee encoder who might be able to help during a quiet period. Give yourself plenty of time to get the DCP made as you may have to wait a while. 

If it’s for a festival, see if the festival can do a deal with a lab. If they’re doing 20 DCPs all at once it can be much more affordable for each film-maker. But be cautious. Make sure the lab are experienced, use proper kit and, again, make sure they have a test cinema.

If you want to ask SDC, please do. We sometimes do discounted jobs to help the industry for those genuinely in need. Drop us an email and tell your story. No promises, but we will look at it and get back to you.

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