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How to create a DCP with OpenDCP

Update: Please check out my new website myonlinedcp.com. It is the most convenient way to create a DCP. Simply paste a link to your film into a text field and receive a download link to your DCP 48 hours later.

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A "Digital Cinema Package" (DCP) is the modern standard of digital cinema projection. It has replaced 35mm film. The main advantages over other digital container formats are that a DCP looks exactly the same in any DCI licensed cinema across the world and can display all the colors the human eye is able to see.

To create a DCP of your film for free you can download the open source software OpenDCP and follow my guide below. Please read it carefully, since small errors in the process lead to bigger errors during the projection.

For further information read the OpenDCP FAQ and Documentation.


Source Material

1. Picture: Tiff sequence, 8-bit / 12-bit or 16-bit, 1998 x 1080 quadratic pixels (not 1920 x 1080!)
2. Sound: WAV file, 24-bit, 48 khz or 96 khz, Stereo, 5.1 or 7.1

The most widespread DCI standard "Interop" only supports a frame rate of 24 frames per second.
But most DCI servers around the world also support the newer SMPTE standard. It features frame rates of 24, 25, 30 or more images per second.

It is very important that the image sequence and the sound file have the exact same duration. A difference in the duration might lead to unexpected results during the projection.

Oftentimes you will only have a 16-bit WAV sound file. You will have to convert it with Quicktime Pro, Adobe Media Encoder or Audacity (free) to 24-bit beforehand.

Delivery

A small DCP may be sent over the internet.A DCP that is smaller than 4GB can be delivered on a FAT32 formatted USB-Stick. The two methods above are the most hassle free ways of delivery. If you want to create a 100 percent DCI compliant DCP, you will have to put it on an EXT2 or EXT3 formatted hard drive with an MBR partition table and an I-Node size of 128. I will create a separate tutorial for that.

Please create a ZIP archive of the DCP folder before you upload it or copy it to another location. Otherwise you might run into a "bit flip" and the DCP server will not be able to load the DCP. Bit flips happen frequently when you copy files. One bit changes its value from one to zero or the other way around.

Step 1: The Title Generator

There are four tabs at the top of the OpenDCP interface: JPEG2000, MXF, Subtitles and DCP. These represent the individual steps we need to take to create a DCP. I will not discuss subtitles here. The easiest and safest way is to render them into your Tiff sequence before going into OpenDCP.

We will start in the DCP tab and click on the "Title Generator" button on the top right. It is important to fill out as many fields as possible. The projectionist will use the title to check the frame rate, aspect ratio and more for a correct projection. Use the image below as a guide. For a more in-depth explanation check the OpenDCP Documentation.

OpenDCP Title Generator

Step 2: Create some folders

Copy the title out of the title field in the DCP tab. Create a new folder and name it like the title. In my case: THE-TITLE_SHR_F_DE-XX_DE-AA_20-DE_2K_20140118_2D_OV. This is your DCP folder. A DCP is not a single video file, it is a whole folder.

Now create a folder for your Tiff sequence and name it "the_title_tiff_sequence" (obviously replace "the_title" with your title). Furthermore create a folder for the JPEG2000 sequence and name it "the_title_j2c_sequence". Next paste your sound file into the project directory.

Create the DCP project folders

Step 3: JPEG2000 conversion

Go to the "JPEG2000" tab. We will now convert the Tiff sequence to a JPEG2000 sequence. As the input directory choose your "the_title_tiff_sequence" folder. The output folder is your "the_title_j2c_sequence" folder. Adjust the settings as in the image below and hit "Convert". Again for more information on the parameters use the OpenDCP Documentation. If you encounter artifacts in your images, try setting the bandwidth value to 180 mb/s. But usually values higher than 125 mb/s only increase the file size without a change in quality. In my experience even 50 mb/s look great with most movies. Try it, the file size will decrease dramatically!

JPEG2000 images will look strange on your computer, because the color space is being transformed from sRGB to XYZ during the conversion. But dcp player software and the DCI projector in the cinema will interpret them correctly.

Update: Since version 0.30 OpenDCP uses a different sRGB -> XYZ color transform. If your source material is output from Adobe software, please use sRGB or Rec.709 as your source color. If not, use "sRGB complex" or "Rec.709 complex". If the colors of your DCP look wrong, you might have chosen the wrong source color.

Create a JPEG2000 sequence

Step 4: Create the Video-MXF

Go to the "MXF" tab. MXF is a container format like Quicktime or MP4. The JPEG2000 sequence will be embedded into an MXF now. Use the settings below. Make sure that the frame rate matches the frame rate you used during the JPEG2000 conversion.
The picture input directory is the "the_title_j2c_sequence" folder. The output file goes into your DCP folder (THE-TITLE_SHR_F_DE-XX_DE-AA_20-DE_2K_20140118_2D_OV). Name it "the_title_pic.mxf". Now press "Create MXF".

Wrap the JPEG2000 sequence in an mxf

Step 4: Create the Sound-MXF

The sound file also has to be converted to an MXF. Still in the "MXF" tab, change the type from JPEG2000 to WAV and use the settings as shown in the image below. If you get any errors, please read the specifications of the source material at the top of this page again.

Turn the sound wav into an mxf

Step 5: Create the DCP

Now that we have created both the picture and sound MXFs, we need to generate a couple of XML files that tell the DCI server where to put your film and how to play it (aspect ratio, frame rate, etc.).

Again use the image below as a guide. Make sure that the duration of the picture and sound are the same. If they differ OpenDCP will not let you create the DCP. You can get away with adjusting the duration with the up and down arrows to the right of the frame number, but I would not do this. It is more save to go into your "the_title_j2c_sequence" folder and add or delete frames until the number of frames matches that of the sound file. Beware that the JPEG2000 sequence starts at frame 0! Then create the video MXF again.

Now press "Create DCP" and wait for the "DCP created successfully" popup window.

Create the XML files to finish the DCP

Step 6: Checkup

In the end your DCP folder should contain the following files:

75c6de53-04b6-4b21-915f-2a459ec3ee80_cpl.xml
ASSETMAP.xml
eafc3369-d452-45b9-bb61-c2fcf78ef8f2_pkl.xml
the_title_pic.mxf
the_title_sound.mxf
VOLINDEX.xml

The keys of the "_cpl.xml" and the "_pkl.xml" are only examples and vary from DCP to DCP.

Step 6: Test the DCP

Please check your DCP before delivering it to festivals etc.! There are many things that can go wrong and you can end up with elevated blacks, compression artifacts or simply an invalid DCP that most DCI servers won't play.

To check the image and sound quality of your DCP, download the trial version of NeoDCP Player. The trial expires after a month or so and shows a logo on top of the film. The playback stops once every minute, but this way you can check for synchronicity and compression artifacts. The basic version of NeoDCP Player is only 79 Euros.

To check for "bit flip" errors after copying the DCP folder, download the trial version of the easyDCP Player. Load the "ASSETMAP" file in your DCP folder into easyDCP Player and press the "h" key on your keyboard. This will open up the "Hash Check" dialog window. If the hash check fails, remember to ZIP your DCP folder before copying. Note that the trial version only plays the first 15 seconds of a DCP.

For a final check you may also visit your friendly projectionist at your local movie theater and ask him or her to ingest your DCP into the server.

Shameless self promotion

If you don't want to go through the time consuming process of creating a DCP yourself, please visit my new DCP website myonlinedcp.com. Through automation My Online DCP can offer DCPs for up to 85 percent below the price you pay everywhere else.
The DCPs have great quality and small file sizes, so that they can be distributed over the internet very well. So, go ahead and create a DCP now!