Since it was the first time this year but not the only time remained that our moving pictures came to the cinema, I would like to write here a small, compact guide and share the painstakingly acquired knowledge of how to prepare a video so that it runs wonderfully “on the very big screen”. Of course there is software for everything and with money you can buy everything, but there is always another way and thanks to open-source a way to create a “cinema-ready” DCP file for free.
Traditionally, video and cinema have been somewhat at odds: we remember legendary buzzwords such as 35mm, film and “captured on celluloid”. The history of cinema also evolved parallel to photography from the analogue to the digital age, albeit somewhat later. I don’t want to go into technical details, even if they are admittedly exciting, such as the XYZ color space, and will limit myself to the pure process of converting a video that was created with the usual tools(Lightworks, Premiere, AfterEffects, etc.) to (digital) “film” for the cinema.
At the heart of the workflow is the small but powerful tool OpenDCP, available for Windows, Linux and MacOS. That’ll do whatever it takes. Of course there are also commercial solutions like easyDCP Creator from Fraunhofer Institute – where the mp3-format was invented and the online revolution of music was proclaimed – but with more than € 2.300,- it is not exactly a bargain and was therefore out of the question for our purpose and need.
First of all, it should be noted that in the DCP cinema format – 35 millimeters say hello – we traditionally have only 24 frames per second, while video usually has 25 frames per second or “frames per second” (fps) in full screen (i.e. “progressive”, no (“interlaced”) fields). This is important because otherwise at some point the picture and sound will no longer run synchronously. This adds up: after 25 seconds of video or “film” the sound is already a second behind, so watch out! If in doubt, simply pitch the note minimally (make it faster) at the same pitch. Therefore in the following always pay attention to the number of frames, OpenDCP always shows them. If in doubt, just export the video again at 24fps and extract the audio.
The picture or video is mostly in FullHD with 1920 x 1080 pixels, which can be – with minimal margin – directly brought into the“Cinema 2K” format (1998 x 1080 pixels “Flat” or 2048 x 1080 “Full”). If the production was in full “UltraHD” or also called UHD with 3840 × 2160 pixels, the “Cinema 4K” format is of course the best choice. However, there the edge becomes somewhat larger, because in the 4k-Cinema
Full Flat format the number of pixels is 4096 3669 x 2160, i.e. larger edge than with HD-to-2k, unsightly “stretching” or scaling and cropping … Alternatively, simply work in the correct resolution. On the safe side is who uses a resolution of 1998 x 1080 (cinema standard 2K; 1 : 1.85; flat), not all cinemas use 4k projectors.
First download and install the said OpenDCP and for editing the audio we need the fine audio tool Audacity then the rest goes quite easily in the following steps:
Before the human player in the technical room of the cinema scolds, we recommend the free (test version) of the Fraunhofer Player called easyDCP Player which is available for download here, the registration can be kindly skipped. The player only plays the first 15 seconds, but that’s enough to see if the movie is playing at all. It also gives out informative messages such as:
Code 35189 from Wed Nov 01 20:01:14 2017:
Audio and video length does not match.
Audio track duration is 00:01:59:21
Video track duration is 00:02:00:00
Which is now for me and now means fix the soundtrack because three frames are missing and end this post…. ;)
I am looking forward to further tips & tricks, experiences and comments and wish you a lot of fun!
If you want to delve deeper into the subject, you can find a more comprehensive description in English and many more details on the subject here on The Film Bakery. The “cinema”photo is by Pedro and published under CC-BY-2.0 license.