DCP Basics for a Festival or Pop-Up

A festival that says "send a DCP" is not asking for an H.264 file on a USB stick. A Digital Cinema Package is the theatrical cousin of an IMF package: JPEG 2000 picture in MXF, uncompressed PCM audio in MXF, and a small set of XML files that tell a cinema server what to play. Brand films and AI shorts are showing up in that pipeline now, and the failure mode is always the same. Someone sends a ProRes, the projectionist cannot ingest it, and the "backup" MP4 looks like a laptop night.

You do not need a lab for a one-night unencrypted screening. You do need to pick 24 or 25, 2K or 4K, and a loudness language that is not EBU R 128, and you need to test the package in a player that is not QuickTime.

What a DCP actually contains

The Digital Cinema Initiatives system specification is the industry document. A DCP is the compressed, packaged form of a Digital Cinema Distribution Master. Picture is JPEG 2000 (ISO/IEC 15444-1) in an MXF wrapper. MPEG-2 is not DCI-compliant. Audio is 24-bit linear PCM, 48 kHz, in its own MXF. Subtitles, if any, are a separate timed-text asset, not burned social captions.

The XML side looks familiar if you have seen IMF, because IMF borrowed the shape:

• CPL (SMPTE ST 429-7): the composition. What plays, in what order.
• PKL (ST 429-8): the inventory, with hashes.
• ASSETMAP and VOLINDEX: where the files are.

Two packaging dialects still matter in the field:

• Interop (IOP). Older. Frame rate for a reliable Interop composition is 24 fps. Plenty of festival servers still prefer it.
• SMPTE DCP. Current. SMPTE packaging allows 24, 25, and 30 fps at 2K and 4K, and higher rates at 2K. Netflix's own DCP spec notes Interop must be 24 fps, and SMPTE may be 24, 25, or 30 at 2K or 4K.

Ask the festival which dialect they ingest. If they do not know, 24 fps Interop 2K Flat, unencrypted, is the boring package that still plays. CalArts' DCP-o-matic notes make the same warning: SMPTE may not play on every server; if the festival specified Interop, choose Interop.

Color is the other surprise. DCP picture is stored as 12-bit XYZ (DCI), not Rec. 709. A tool like DCP-o-matic converts Rec. 709 (or P3) on the way in. If you skip the conversion, the screening looks wrong, often dark or green. Grade in the space you know, convert at wrap, and look at the result in a DCP player, not in the NLE.

JPEG 2000, 2K versus 4K, 24 versus 25

JPEG 2000. Intra-frame, lossy at a DCI maximum of 250 Mbit/s for standard dynamic range. That number is a ceiling, not a quality target you have to hit. A two-minute brand film at 2K will be a few gigabytes, not a 200 MB MP4. Budget the drive, not the email.

2K versus 4K, DCI containers:

Name	2K	4K	Aspect
Full container	2048×1080	4096×2160	~1.90
Flat	1998×1080	3996×2160	1.85
Scope	2048×858	4096×1716	~2.39

HD 1920×1080 is not a DCI container. A 16:9 brand film usually goes Flat, with small side mattes inside the 2048 (or 4096) container, or it is letterboxed in Full. Scope is for 2.39 sources. Do not pad a 9:16 social cut onto a cinema screen and call it a DCP. Either recut to a theatrical ratio, or accept that this booking is a different edit.

4K is not free quality. If the source is a 1080p generation, a 4K DCP is an upscale in a tuxedo. Festival projectionists will still play it. It will not look like a 4K native master. Generate at the highest resolution the model actually supports (the 4K video models, cinematic widescreen picks), or wrap 2K honestly. How resolutions work is the generation-side version of this choice.

24 versus 25. Theatrical convention is 24. Versely's editor defaults to 25. Almost no video model in the catalog offers 25. 24 fps clips on a 25 fps timeline is the conform you already owe; for a DCP you then have to pick the playback rate.

• If the festival is Interop, you need 24. Conform 25 to 24 before wrap, or generate at 24 from the start.
• If the festival is SMPTE and in a 25 fps country, a 25 fps SMPTE DCP can be the honest wrap of a 25 fps master. Confirm the server.
• Do not wrap 25 fps into an Interop 24 fps DCP by changing the flag. Duration and pitch will be wrong.

Frame interpolation versus native frame rate is a generation trick, not a DCP trick. Do the rate conversion in the NLE, watch the result, then wrap.

Loudness, and why R 128 is the wrong number here

Cinema mix is not broadcast mix. EBU R 128 at −23 LUFS is a broadcast target. Play that file in a theatre calibrated to the usual 85 dB SPL fader reference and it will feel quiet against every trailer in the block.

Trailer and commercial loudness in theatres is measured as Leq(m), not LUFS:

• TASA (Trailer Audio Standards Association): current published upper limit 85 dB Leq(m) for trailers.
• Cinema commercials are commonly held to 82 dB Leq(m) (the SAWA figure used next to TASA in the field).

There is no equivalent official cap for features or shorts. A two-minute brand film in a festival block should not be mixed like a TASA trailer and should not be mixed like a radio commercial. If you only have an R 128 meter, do not print −23 and hope. Mix in a room (or on headphones you trust) so dialogue sits comfortably, peak without clipping the PCM, and then check Leq(m) if you have the meter. Loudness normalization is the broadcast explanation; this paragraph is the reason that explanation does not travel to a DCP.

Audio layout: stereo is acceptable for a brand film or a short. 5.1 is fine if you actually mixed 5.1. Do not upmix with a "surround" preset you have not heard in a room. Channel order on a DCP is not the same as a YouTube stereo pair; the wrapping tool will ask. Answer it.

A KDM-free package for one night

Feature DCPs on the commercial circuit are usually encrypted. Playback then requires a KDM (Key Delivery Message, SMPTE ST 430-1) issued to that specific cinema server, for a specific time window. That is a lab and a serial-number conversation.

A festival short, a brand pop-up, a one-night hire: unencrypted, no KDM. Short films, advertisements, and trailers are commonly distributed that way. In DCP-o-matic the control is a checkbox (Encrypted: off). In a commercial wrapper it is the same idea. If the festival did not send you a server certificate, they are expecting unencrypted.

A one-night checklist:

1. Finish the picture at a theatrical ratio. An AI short still needs a locked cut, a hold on the tail, and credits that a projector can read.
2. Conform to a single frame rate. Prefer 24 if anyone in the chain said Interop or said nothing.
3. Mix for a theatre, not for a phone.
4. Wrap JPEG 2000, 2K Flat or Scope, Interop or SMPTE as specified, encryption off.
5. Name the composition so a projectionist can find it on a server list (ISDCF's Digital Cinema Naming Convention exists for this; a human-readable title plus FTR-1_2K_s_24 is better than export_final).
6. Copy the folder to a drive. ExFAT is the boring choice that Mac and Windows both mount. Do not put the DCP inside a zip on the drive unless they asked for a zip.
7. Play it back in DCP-o-matic Player (or another DCP player) on a different machine. Watch the first minute and the last minute. Confirm the CPL title. Confirm there is no KDM prompt.
8. Bring a second copy of the drive, and a programme-only ProRes as a last-resort backup the venue may refuse. The DCP is the show copy.

Versely does not wrap DCPs. Generate and assemble there (text to video for the plates, the editor for the cut), then wrap in a DCP tool. Do not ask a model to "make a DCP." You would get a video of a folder.

FAQ

Will an unencrypted DCP play on every server?

It will play on every server that is willing to ingest unencrypted content, which is the normal festival and pop-up case. A commercial chain that only ingests encrypted features will not. If the booking is a chain, ask. If the booking is a festival, unencrypted 24 fps 2K is the package they have ingested a hundred times.

Can I wrap a 9:16 AI short as a DCP?

You can put any raster in a container. You should not. A vertical video on a 1.85 screen is side-curtains and a small picture. Recut a theatrical version, or project from a computer as a special-venue exception, with the venue's agreement. A DCP of a phone video is how you look unprepared, not how you look experimental.

Do I need 4K if the screen is 4K?

Only if your source is. A 2K DCP on a 4K projector is a daily occurrence; the projector scales. A 4K DCP of a 1080p generation is extra data and extra wrap time for an upscale. Match the DCP to the source, not to the marketing of the venue.

What if they ask for a KDM anyway?

Then they have an encrypted workflow, and you need their server certificate (or a list of them) and a wrapper that can encrypt and issue KDMs. For a one-nighter, push back once: "We can send unencrypted SMPTE 2K, no KDM." If they insist, you are in lab territory, and the USB you were going to hand the projectionist is no longer the whole delivery.