If you've delivered content to Netflix, Disney+, or Amazon Prime Video recently, you've probably encountered the IMF (Interoperable Master Format). It's replacing traditional file-based delivery as the standard way streaming platforms receive content. Here's what you need to know as a filmmaker or producer — without the engineering jargon.
What Is IMF?
IMF is a standardized packaging format for delivering finished content to distributors and platforms. Think of it as a structured container that holds your video, audio, subtitles, and metadata in a way that any compliant platform can ingest, verify, and distribute. It's defined by SMPTE (the Society of Motion Picture and Television Engineers) and has become the de facto delivery standard for premium streaming content.
The key difference between IMF and traditional delivery: instead of delivering separate master files for each version of your content (one for Netflix, one for Disney+, one for international markets), IMF packages a single master with "supplemental" packages for each variation. Need a version without the opening credits? A version with different subtitle languages? A version with an alternate audio mix? Each is a supplemental package that references the original master — not a complete duplicate.
Why Platforms Require It
From the platform's perspective, IMF solves several expensive problems. It eliminates the file duplication inherent in traditional delivery (a single IMF master replaces dozens of separate files). It standardizes quality control (the format has built-in validation that catches errors before content enters the distribution pipeline). And it enables efficient versioning — when a platform needs to create a regional variant, they modify the supplemental package rather than re-mastering from scratch.
For filmmakers, this means fewer QC rejections (the format enforces compliance with technical specifications), faster time-to-publish (platforms can ingest and validate IMF packages automatically), and lower long-term cost (your single IMF master serves all distribution channels).
What's Inside an IMF Package
CPL (Composition Playlist): The "recipe" that tells the player how to assemble the content — which video track, which audio tracks, which subtitle tracks, in what order.
Track files: The actual media — video (typically JPEG 2000 encoded, like a DCP), audio (PCM, uncompressed), and timed text (subtitles, closed captions).
OPL (Output Profile List): Platform-specific metadata that defines how the content should be transcoded for different devices and bandwidth conditions.
PKL (Packing List) and ASSETMAP: Inventory files that catalog everything in the package and tell the ingest system where to find each component.
The IMF Delivery Workflow
Step 1: Complete your post-production. Color grade, sound mix, VFX — everything needs to be finished before IMF packaging begins. IMF is a delivery format, not an editing format.
Step 2: Create the IMF master. Your post facility encodes the video as JPEG 2000, packages the audio stems, integrates subtitle tracks, and builds the CPL that ties everything together. This is done using specialized IMF tools — most commonly Marquise Technologies MIST, Colorfront Transkoder, or Fraunhofer easyDCP.
Step 3: Validate. Before delivery, the package is validated against the platform's specific IMF specification. Netflix, Disney+, and Amazon each have slightly different requirements. Validation catches encoding errors, metadata issues, and specification non-compliance.
Step 4: Deliver. The completed, validated IMF package is uploaded to the platform's content ingest system — typically via Aspera or a platform-specific delivery portal.
Korean IMF Capability
Korean post-production facilities working with Netflix and other streaming platforms have invested heavily in IMF capability. The facilities that regularly deliver Korean originals to Netflix have been through dozens of IMF delivery cycles and understand each platform's specific requirements, common rejection reasons, and QC standards. This experience is directly transferable to international projects finishing in Korea.
The advantage of mastering your IMF in Korea — especially if your color grade and sound mix were done there — is continuity. The same facility that created your finished masters packages and delivers them, eliminating the handoff errors that occur when mastering happens at a different facility than finishing.
For the full list of platform-specific delivery specifications Korean facilities handle, see our Platform Deliverables page. For more on the overall Korean post-production pipeline, read our Complete Guide.
Why IMF Replaced Traditional Delivery
Interoperable Master Format (IMF) emerged because traditional master delivery had a scaling problem. When Netflix needed to deliver a single film in 30 different language versions with different subtitle and caption variations, the old approach — one complete master file per version — became unmanageable.
IMF solves this through component-based packaging. The core visual and audio elements are packaged once. Each version variation (different languages, different subtitle sets, different editorial versions) is a "supplemental" package that references the core content with specific variations applied.
This structure means a single IMF package can represent hundreds of versions of the same content without duplicating the underlying material. For global streaming platforms, this is the only practical way to manage the scale of content localization.
Anatomy of an IMF Package
Composition Playlist (CPL). The XML file that describes which assets combine to form a specific version. This is where "version" is defined — a specific sequence of picture, audio, and subtitle components.
Output Profile List (OPL). Describes how the composition should be rendered. Includes timing, aspect ratio, color space, and output format specifications.
Asset Map. XML file that lists every asset in the package and its location. Used during validation and ingestion.
Packing List (PKL). Cryptographic hashes of all package components, ensuring integrity during transfer and ingestion.
Picture track files. JPEG 2000 compressed picture in MXF wrapper, typically at original resolution (UHD for 4K deliverables, HD for 2K deliverables).
Audio track files. PCM audio in MXF wrapper. Multiple language tracks, multiple surround configurations, Dolby Atmos BWF ADM streams all packaged as separate assets.
Subtitle and caption assets. Timed Text XML files (TTML) for subtitles, caption tracks, and accessibility tracks.
Supplemental packages. For versioning: alternate edits, language-specific versions, platform-specific variations. Each supplemental package references the base composition and applies variations.
IMF Validation: What Gets Checked
Before Netflix or any streaming platform accepts an IMF package, it runs through extensive validation:
Schema compliance. All XML files must validate against IMF schema. Even minor formatting issues trigger rejection.
Asset integrity. Every file's hash must match the hash declared in the PKL. Any file corruption during transfer causes rejection.
Reference validity. Every asset referenced in the CPL must exist in the Asset Map. Every file in the Asset Map should be referenced somewhere. Orphaned or missing references cause failures.
Technical compliance. Picture codecs, audio codecs, frame rates, color spaces, and resolutions must all match the declared specifications. Automated QC tools flag discrepancies.
Supplemental validity. Supplemental packages must correctly reference their base composition and apply only valid variations.
Why Packaging IMF Correctly Requires Experience
The IMF specification is over 500 pages of technical detail. Different streaming platforms interpret the specification with platform-specific preferences. A package that passes Netflix IMF validation may fail Disney Plus validation due to a subtle specification difference.
Facilities with repeated IMF delivery experience have seen the edge cases. They know that Netflix prefers specific CPL structures. They know that Amazon has specific metadata expectations. They know that Apple TV Plus has tighter subtitle validation than competitors.
This institutional knowledge is not in the specification documents. It comes from delivery experience and accumulated feedback from platform technical operations teams. Facilities with 50+ IMF deliveries to Netflix alone have essentially internalized the platform's preferences.
IMF Packaging in Korean Facilities
Korean facilities that deliver Korean originals to Netflix (and there have been hundreds of such deliveries since Netflix's Korean investment began in 2015) are experienced IMF packagers. They know the Netflix preferences, have automated their packaging pipelines to match, and troubleshoot IMF validation issues quickly when they arise.
For international productions, working with experienced Korean facilities eliminates the learning curve that smaller or less experienced facilities would have to climb. The IMF package arrives at Netflix correctly structured on the first submission. QC passes. Delivery completes on schedule.
IMF Cost Factors
IMF packaging is typically scoped as a specific deliverable with defined pricing:
Base IMF package (single language, single edit). $3,000-$6,000 for Korean facility, $6,000-$12,000 for LA facility. Includes CPL, picture and audio assets, primary subtitle track, validation.
Each supplemental package (additional language or version variation). $500-$1,500 Korean, $1,200-$3,000 LA. Multiple supplementals scale the cost linearly.
Subtitle and caption integration. Typically $200-$500 per language Korean, $500-$1,200 LA. Includes formatting validation and sync verification.
A typical international release requiring IMF with 10 language versions runs $8,000-$15,000 in Korea, $20,000-$35,000 in LA. The savings compound as version count increases.