How to make your own DCP with DCP-o-matic.

Oct 27

4 min read

You can make a DCP that plays in a real cinema on the computer you edited on, with free software. Plenty of filmmakers do. The tool is DCP-o-matic, and this post walks through it from an empty project to a verified package on a drive.

If you skipped ahead, go back to last week’s post on prepping your master. Everything here assumes your picture is locked, your audio is in discrete channels and you know your frame rate and color space. If you’re still deciding whether DIY is worth your time, week three has the comparison.

About the software.

DCP-o-matic is free and open-source under the GPL. Carl Hetherington is its main author and maintainer. It runs on Windows, macOS and Linux, and the current stable release is 2.18.50, from September 8, 2026. It ships as a family of tools: the main program, a player, a verifier, a KDM creator, a combiner and a disk writer. You’ll use four of them today.

Sergio Andrés Lobo-Navia’s festival delivery guide in Filmmaker Magazine recommends it with three conditions worth copying onto a sticky note: “If you use it for your film, please make sure to read the manual, test your DCP in a theater before sending it to a festival and also tip main author Carl Hetherington, who is unusually responsive to emails and has made everyone’s life much easier.”

Read the manual. It’s good. What follows is the path through it.

Step 1: Make a new film.

Download DCP-o-matic from dcpomatic.com. Open it and choose New from the File menu. Name the project and pick where it lives.

Pick that location carefully. The manual warns: “DCPs can be very large (more than 100GB for a feature-length DCP) so it’s important to choose a folder on a disk with plenty of free space.” Use a fast external SSD or a big internal drive with room to spare.

Step 2: Add your content.

Click “Add file(s)...” and choose your master. If your picture and sound are separate files, add both. DCP-o-matic reads the files and shows a preview you can scrub through.

Now open each piece of content and check what DCP-o-matic assumed about it:

Video frame rate. Make sure it read your master correctly, especially at 23.976.
Crop and scale. If your 2.39 film has letterbox bars baked into a 16:9 master, crop them off here.
Color conversion. Set it to match your master, usually Rec. 709. This is where last week’s note from your colorist gets used.
Audio mapping. DCP-o-matic shows a grid of your input channels against the cinema outputs. Make sure dialogue goes to Center in a 5.1 mix, and that Left, Right, LFE and the surrounds land where they belong. Five minutes here saves a festival screening.

Step 3: Set up the DCP.

Open the DCP tab. These are the settings that matter:

Name, with “Use ISDCF name” ticked. DCP-o-matic builds the standard name from your settings. The manual says the name doesn’t affect playback but “projectionists will appreciate it if you use the standard naming scheme.” Week seven decodes that name.
Content Type. FTR for a feature, SHR for a short.
Encrypted. Leave it off unless a distributor has asked for encryption. Week twelve explains why.
Standard. SMPTE. The manual’s advice: “If in doubt, use SMPTE (the more modern of the two).” The Academy requires it.
Container. Flat (1.85) or Scope (2.39), matching how you framed the film.
Resolution. 2K, unless you have a true 4K master and a venue that wants 4K. The manual: “Use 2K unless you have content that is of high enough resolution to be worth presenting in 4K.”
Frame Rate. 24.
JPEG2000 bandwidth. The manual notes that “Most commercial DCPs use bit rates between 75 and 125 Mbit/s.” The legal ceiling is 250. Staying in the commercial range keeps your files a sensible size with no visible loss.
Channels. Six for 5.1. Stereo is fine too.

Step 4: Make the DCP.

Choose Make DCP from the Jobs menu. DCP-o-matic runs its own checks first and lists anything that looks wrong: a frame rate mismatch, missing audio, a naming problem. Read every hint. You can choose “Make DCP anyway” or “Go back.” Go back unless you’re sure.

Then it encodes. Every frame of your movie is compressed to JPEG 2000, which is slow work. On a laptop, a feature can take several hours. Start it before you go to bed. DCP-o-matic can also spread the job across other computers on your network as encoding servers, if you have spare machines.

When it’s done, the DCP sits in its own folder inside your project folder.

Step 5: Verify it.

Open DCP-o-matic Verifier and point it at the finished DCP folder. It reads the package the way a cinema server will, checks every file against the checksums in the packing list, and reports “Errors,” “Bv2.1 errors” and “Warnings.” Bv2.1 is the current industry profile for SMPTE DCPs.

Errors must be fixed. Warnings deserve a read. A clean verification report is your first real evidence the DCP will ingest.

Step 6: Watch it.

Open the DCP in DCP-o-matic Player and watch the whole thing. Beginning to end. Your laptop may not keep up at full resolution, and the player will drop to a lower resolution to keep playing. That’s fine. You’re checking for:

sync from the first line to the last,
the right sound in the right channels,
subtitles appearing when and where they should,
the correct aspect ratio with nothing cropped,
no black frames, flash frames or missing shots.

Step 7: Write it to a drive.

Theaters want DCPs on drives formatted for Linux. Mac and Windows can’t create that format on their own, so DCP-o-matic includes a Disk Writer that “allows you to format and copy DCPs onto ext2-formatted disks from Windows, macOS or Linux.” Plug in the drive, choose it in Disk Writer, choose your DCP, and write. It erases the drive first, so use a dedicated one.

Week eleven covers which drive to buy and why ext2 matters.

Step 8: Test it in a theater.

Everything you’ve done so far happens on a computer. The last check happens in a booth. Week twelve covers how to get that test, and what to watch for when you do.

If you get stuck anywhere in this process, or you’d rather hand the whole thing off, our DCP service covers the same ground: QC on the master, mastering, packaging, validation and drive prep.

Next week we open the folder you just made and look at every file inside it.