Interoperable Master Format: Difference between revisions

Revision as of 13:38, 9 May 2022

Revision as of 14:32, 9 May 2022

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= Architecture =

At the heart of IMF is the Composition, illustrated in the first image, which consists of a single Composition Playlist and a collection of Track Files. Each Composition corresponds to a single audio-visual master.

[[File:IMF_CompositionIMF Composition (CPL) Example.png|alt=An IMF Composition is defined by a Composition Play List|thumb|IMF Composition Example]]

Each Track File contains a single kind of essence corresponding to a single aspect of the presentation. For example, a first Track File might contain the primary video program while a second might contain Spanish stereo audio and a third English subtitles. Track Files use a constrained version of the MXF OP1a format [[Material Exchange Format]]

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The primary benefit of separating the Composition Playlist from the Track Files is that a Track File can be reused across multiple Compositions as shown in the second image. Each Composition represents a different version of an audio-visual work. Since different versions of a title typically differ in small ways and this component-based approach results in smaller files, fewer quality control passes and fewer resources expended on mastering the multiple versions. For example, a censored version of a movie might differ in only a few video frames from the original. Instead of having to deliver or store two largely identical versions, IMF allows the censored version to reuse the Track Files of the original version.

[[File:IMF_Track_File_ReuseIMF Track File Re-use Example.pngsvg|alt=IMF can re-use Track Files to minimize resource usage for versions of audio-viual works.|thumb|IMF Track File Reuse]]

= Specifications =