Making a Digital Cinema Package

The finished Stop/Eject DCP. Not as cool as a roll of 35mm.
The finished Stop/Eject DCP. Not as cool as a roll of 35mm.

Now that huge reels of 35mm film are all but obsolete, Digital Cinema Packages (DCPs) are the new means of getting a film to a cinema. Many top film festivals will only screen off a DCP or 35mm print, and in terms of picture and sound quality and compatibility it is your best option for screening at theatrical venues in general. Much has been written about how you can make a DCP at home for nothing, but having just gone through the process myself for Stop/Eject I’m going to round up some of the best sources of information I came across and enlarge on the area of disc formatting which hasn’t been too well covered elsewhere.

To ensure maximum compatibility of your DCP you need to:

  • convert your film to 24fps if it isn’t already at that frame rate
  • use a standard 2K aspect ratio, 2048×1080 or 2048×858
  • put it on a disc that is EXT3 formatted
  • supply that disc in a Cru Dataport DX-115

I’ve spoken to filmmakers who have ignored many or all of the above and still run their DCPs successfully in cinemas, but I decided to play it safe and do all of the above, except the Cru Dataport, which was a little too expensive. Instead I bought a 500GB LaCie Rugged USB drive and put my DCP on there. Read Knut Erik Evensen’s excellent blog post on DCP delivery for more info on Dataports and USB compatibility.

The formatted drive as seen in Ubuntu, with the DCP files copied over
Step 5: the formatted drive as seen in Ubuntu, with the DCP files copied over

So, here is the process I went through. I was starting out with 25,409 uncompressed 16-bit TIFF files representing each individual frame of Stop/Eject, and six mono 24-bit linear PCM WAV files for the 5.1 surround soundtrack. The TIFFs were in 1080P (1920×1080) letterboxed to an aspect ratio of 2.35:1.

  1. First of all I used Photoshop to batch convert all the TIFFs to the 2048×858 aspect ratio. This is actually 2.39:1 rather than the 2.35:1, so it meant cropping a sliver of the actual picture off the top and bottom, not just the black bars, as well as enlarging the picture slightly. It took my poor iMac about 12 hours to convert the 25,409 frames. I’m sure there’s quicker batch conversion software out there than Photoshop if you hunt around though.
  2. Next I used a free piece of audio software called Audacity to slow down each of the six audio files by 4% so that they will match the images when they run at 24fps. (Stop/Eject was shot and edited at 25fps.) Thanks to Matt Cameron’s blog for this tip.
  3. Then I downloaded and ran OpenDCP, the brilliant free software that actually creates the Digital Cinema Package for you. It’s very simple to use, but check out the help Wiki and Danny Lacey’s seminal blog post to guide you through it. The end result was six files: four XML files and two MXF files, one for sound and one for picture. Encoding at the default bitrate of 125mb/s, which the Wiki says is more than good enough for 2K at 24fps, Stop/Eject’s DCP was just under 17GB, so about 1GB per minute.
  4. Now the tricky bit – copying those six files onto an EXT3 formatted drive. EXT3 is a Linux file system, and is not supported by MacOS. So I downloaded Ubuntu, a free operating system which does support it. (Choose the 64-bit download unless you have quite an old computer.) The downloaded file is a disc image (.ISO) which you can burn to DVD using Disk Utlity (found in the utilities sub-folder of MacOS’s Applications folder). Then restart your Mac, with the DVD still in the drive, and hold down C when you hear the chimes. This will boot up your Mac in the Ubuntu operating system. (You can release C when you see the black screen and Ubuntu logo.)
  5. Once Ubuntu was running, I right-clicked the LaCie Rugged in the list of drives in the lower left of the desktop and chose format from the contextual menu. To get more than the default options, I clicked Disk Utility in the dialogue box that came up. I could now select EXT3 as the file system (leaving the other settings at their default values). When I clicked format, Ubuntu didn’t seem to be doing anything, but after a few minutes the Disk Utility showed that the volume had been created. I could then close the Disk Utility, and drag and drop the six DCP files from another hard drive (MacOS formatted) onto my newly EXT3 formatted LaCie. Apparently you can put these files inside a folder if you want, but again to be extra safe I put them in the root directory.

After completing the DCP I took it to the Courtyard, my local arts centre, where head projectionist Simon Nicholls was kind enough to let me test it. To my very pleasant surprise it worked perfectly, uploading at about real time via the Doremi server’s USB 2 socket and playing shortly afterwards with superb sound and picture quality. Much as I love celluloid, the ease and cheapness of this process are breathtaking, the purchase of the hard drive being the only cost. I’ll let you know how I get on running it at other cinemas.

Making a Digital Cinema Package

Leave a Reply