The Complete Guide to Getting Your Film Into Cinema

What You Are Starting With

Most independent filmmakers delivering a DCP for the first time are starting from a 25fps HD (1920×1080) or UHD (3840×2160) stereo master — probably a ProRes export from their editing timeline. That is a perfectly workable starting point. Getting from there to a cinema-ready DCP on a correctly formatted drive involves several distinct technical stages. This guide covers each of them.

Picture — Resolution and Pixel Sizes

A DCP can only exist in one of two container sizes. Flat (1.85:1) is 1998×1080 pixels at 2K, or 3996×2160 at 4K. Scope (2.39:1) is 2048×858 pixels at 2K, or 4096×1716 at 4K. Your image — whatever shape it is — goes into one of these two boxes.

If your film is standard 1920×1080 HD going into a Flat DCP, it is best to simply put it into the 1998×1080 box unscaled with a little bit of black padding on the left and right (Pillar-boxing). For Scope output from an HD master, we would scale that up to fit into 2048×858, which is a 2.39 size.

We have a full article on the two containers here.

Aspect Ratio and Masking

If you are working in a cinemascope aspect ratio, use a precise 2.39:1 crop mask — not 2.35. The scope DCP container is 2048×858, which divides to 2.39. Many crop plugins still default to 2.35, which was superseded in 1970. A 2.35 crop will not fill the DCP container correctly. We have a full article on why 2.35 has been wrong since 1970.

For titles, text and subtitles, maintain a safety margin of at least 10% in from all edges — 20% is safer. These areas survive the scaling and container changes intact.

Colour Space

Cinema projectors operate in XYZ colour space — a wider colour container than Rec.709 (standard video) or Rec.2020. Converting your image from video colour space into XYZ is one of the core technical steps in making a DCP and is handled by our encoding software on a calibrated system. You do not need to do this yourself. What you do need to ensure is that your source file is tagged correctly — that video range files are tagged as video range, and that full range elements have not crept in during your export. We check this on every job.

More information on video range versus full range issue here.

Frame Rate

DCPs support only whole-number frame rates: 24, 25, 30, 48, 50 and 60fps. The fractional rates common in video — 23.976 and 29.97 — do not exist in cinema and must be conformed before encoding.

There is little need these days to convert a short or feature to a 24fps DCP. The vast majority of cases a 25fps DCP will be fine. However, if you do need to convert it is best to ask us to do that in the best way possible.

The cleanest way to do this is a 4% speed change — playing the film fractionally slower. No frames are blended or interpolated; every frame remains a clean discrete image. The result is imperceptibly slower to all but the people closest to the production. We adjust audio pitch to compensate. This is exactly the same process used for decades when transferring European 25fps television content to 24fps film.

For 30fps or 29.97fps content, speed change is not an option. Check your target venues can handle a 30fps DCP, or consider a standards conversion — though this involves frame interpolation and can introduce motion artefacts that are more visible on a large cinema screen than on television.

We have a full article on frame rates here.

Audio — The Cinema Speaker System

A DCI cinema uses at minimum a 5.1 system: Left, Right, Centre, Left Surround, Right Surround, and LFE (low frequency effects). Crucially, the centre speaker — mounted behind the screen — carries approximately 80% of the audio in a typical feature film. This is where dialogue lives. The left and right speakers are much further apart in a cinema than in any domestic stereo setup.

If you deliver a stereo DCP, the centre speaker is unused. Your dialogue, mixed for a stereo image that sits between two close speakers, will spread to widely-spaced left and right speakers and sound hollow. The DCI specification technically permits stereo, but we strongly advise against it for any programme where dialogue clarity matters.

The better option — if you do not have a 5.1 mix — is a pseudo 5.1 upmix. We use Nugen Halo, a neural network upmix processor that extracts the centre channel from your stereo (primarily dialogue) and places it on the centre speaker, while leaving the stereo content in the left and right channels. The result is significantly better than stereo playback in a cinema environment. It is not the same as a proper 5.1 mix done in a calibrated room, but it is the right practical choice for most independent productions without access to a surround mixing facility.

Find out more about upmixing here.

Audio — Loudness

Cinema has its own loudness standard: Leq(M), measured using the Dolby weighting curve. We run a Dolby Leq(M) measurement on your audio before we encode the DCP and check the result against your content type.

Our working targets are: max 86 Leq(M) for a trailer, 82 for a commercial, and a range of 72–80 for a short or feature film. Dialogue level should sit around −31 LKFS. True Peak should not exceed −1 dBTP.

If your audio is outside the appropriate range, we will discuss it with you before making any changes. We can make an overall level adjustment — up or down — but we cannot apply dynamic compression or adjust individual sections. If the mix has dynamic range problems, those need to be addressed in the source before it comes to us.

We will not deliver a DCP that exceeds the guidance Leq(M) for your content type. A film that is too loud will fatigue an audience. A film that is too quiet in a noisy cinema environment will be hard to follow.

Read more about audio level issues here as well as why you should venue-proof your audio mix.

Subtitles — Burned In or Separate

From reliability and absolute control over the look, position and feel of subtitles it is best to burn them in to your picture before sending it to us.

"Soft" subtitles, that can be turned on or off by the cinema give you more options in terms of languages amd audiences but need to be thought through first.

It is possible to add subtitles later to an un-texted DCP by creating a Supplemental DCP or Version File, which just has the subtitles within. We have a greater outline of this here.

Access Materials

To allow greater access to the cinema experience, many festivals and exhibitors are asking for further access materials on DCPs, such as a soundtrack with a narrative description for the visually impaired, or subtitles for the Hard-of-Hearing HOH

While most filmmakers can create their own standard subtitle transcriptions, it is important that HOH subtitles are created by access material specialists who understand the requirements and needs of the hard-of-hearing.

Once those materials have been properly created, they would be supplied to us as an SRT, an XML or an audio file and we can advise on the best ways to incorporate those into a DCP

The DCP Process — What We Do

Once we have your source material and have reviewed it, the DCP process takes 2–3 working days (unless you pay for an overnight rush rate). We convert your picture into XYZ colour space, encode it in JPEG2000 at up to 140 mbps (for 2K) or 240 mbps for 4K, wrap it with correctly formatted PCM audio, apply ISDCF-correct naming and SMPTE metadata, generate checksums for every file, and verify the completed package.

We then check every DCP on a calibrated system with 5.1 monitoring before it leaves us. If we spot something during this review — a levels issue in the source material, a sync problem, an export error — we will flag it to you. At this stage, the encoding work is already done. If the source needs to be corrected and resupplied, we start again from the beginning. This is why we ask you to watch and listen to your source files before sending them.

Encryption and KDMs

An unencrypted DCP plays on any compatible cinema server with no additional setup. An encrypted DCP requires a KDM (Key Delivery Message) — one for each specific projector server, tied to a validity window. Past the expiry, the film will not play, regardless of what any operator does.

For most independent films and festival submissions, we recommend not encrypting. KDM logistics — lost emails, wrong server certificates, expired keys discovered at midnight before a morning screening — are among the most common causes of festival screening failures. Every one of these failures traces back to an encrypted DCP.

Encryption is justified for embargoed premieres where a time-locked KDM is the only reliable way to enforce a broadcast or streaming embargo, and for high-value commercial releases where the administrative overhead is proportionate to the protection it provides. For a short film at a film festival, it is probably not.

If you do need KDMs, they are generated per-server, per-venue, per-time-window. We charge per key. If you are screening at a film festival that will handle multiple screens, they may request a DKDM (Distribution KDM) — this gives their authorised authoring system the ability to generate individual screen keys themselves, rather than requiring a separate key for each screen from us in advance.

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Hard Drive and Delivery

DCPs are usually delivered on Linux EXT2 or EXT3 formatted drives — a format that Windows and Mac computers cannot read without third-party drivers. This is the DCI specification. Drives formatted to Windows NTFS will work on most cinema servers and some cinemas prefer this. We will format correctly to the DCI spec unless the cinema prefers NTFS. More infomration here.

For most films, a standard USB thumb drive is the right choice — light to ship, compact, inexpensive, and compatible with all modern cinema servers. Sometimes if ingest speed is critical, a CRU DX115 drive may be requested but these are quite expensive and harder to obtain these day.

We also deliver via Filemail for online submissions — a managed file transfer service that uses UDP rather than TCP, which gives significantly better throughput for large files and does not suffer the silent corruption issues that affect Google Drive transfers of DCP content. We do not recommend Google Drive for DCP delivery .

All copies are parity checked and hash-verified against the source. A copy that passes hash verification is bit-for-bit identical to the original. We include a test server ingest before any drive leaves us.

We can arrange for delivery via Lansat, Qube and Unique Movietransit although these often need lead time and costs can vary.