The Interoperable Master Format (IMF) can provide the needed leverage to automate media workflows.
“More video content is viewed today than ever before, but with more devices, more choice, more platforms and a fragmented viewing market, how does a content owner use MAM and IMF to improve their business?”
With media and entertainment replacing physical tapes and assets with digital file as a standard for global delivery, the economics of distribution and consumption have turned on their heads. Acceptable costs per title, per platform, have dramatically eroded to the point where high levels of automation are now a necessity for the large content houses and the small producers alike to stay in business.
The Complex Media Value Chain
To streamline international delivery, the SMPTE has published a standard called the Interoperable Mastering Format (IMF, SMPTE ST 2067) which addresses the needs of a title from the point at which it is creatively finished and then travels to various companies for localization, legal compliance fixes, dubbing into new languages, subtitling and other adjustments for consumption around the world. Figure 1 shows that the goal of IMF is to provide a common representation of the versions of a title so that deliverables can essentially be “manufactured” for downstream distribution for different territories and platforms. This process is called mastering.
Figure 1 illustrates how properly implemented IMF workflow can provide a common representation of versions of a title, which enables deliverables to essentially be “manufactured” for different territories and platforms.
The Role Of A MAM Without IMF
When a major international broadcaster might be creating up to 200 versions of each title that gets aired, the storage volume becomes very expensive very quickly. It also becomes unwieldy to be able to see the differences between two versions without access to the editing tool that created those differences. The Media Asset Management (MAM) is therefore limited to the management of the file assets and the metadata and processes that created the version in the first place. There is little auditing or validation metadata that is stored within the media itself.
The Role Of A MAM With IMF
The IMF structure allows the versions to be represented with little or no duplication of audio-visual files and there is a rich, standardized metadata structure that provides the basis for tracking and auditing of the title, the version and ultimately every edit that is used and re-used throughout the lifecycle of the title.
Importantly, IMF does not use filenames to locate media or to define relationships.
How IMF Works With A MAM
IMF is all about composition. Figure 4 shows virtual tracks of video (yellow), audio (red), subtitles (green) and marker metadata (grey). Each separable media element is stored in its own individual MXF Track File which allows these resources to be mixed and matched between different compositions. This differs from the traditional, fully rendered approach where the video, audio and subtitles are all binary encoded and interleaved into a single media file.
This ID rich eco-system allows a MAM to perform several functions without needing to access the media files, or even know their names:
- Determine whether or not all the resources are available for a composition by inspecting the MAM’s internal list of IDs that it manages
- Lookup the Content Version IDs to establish composition relationships outside the scope of IMF
- Determine the timeline properties of the composition (duration, number of tracks, complexity of editing)
- Determine the number of Media Track Files that should be resolved and their IDs
- Determine the requirements of a player or transcoder to be able to process the composition (based on the File Descriptors of the track files)
- Modify the timeline and create a derivative that uses only the media already referenced without needing to access the underlying media track files
The overall change in moving from traditional working to an IMF Supply Chain approach is more than just a technical uplift. It allows a company to really change the way that they engaged with their customers and to change the value model that is presented. All too often a Post-House can be perceived as a provider of tapes and files that satisfy individual creative projects, but the goal here is for an IMF Supply Chain to move to a position of being able to fulfill their customer’s continuous business need by providing a technical back office and potentially a store-front for fulfilling their national and international distribution requirements.
For an IMF Supply Chain, some of the high-level success criteria would enable:
- Significant improvements in automation and efficiency
- The ability to refine and repeat workflows to enable continuous improvement in processes
- The ability to provide services to customers instead of just providing files, for example, the IMF Supply Chain holds a customers’ IMF titles in a vault so that customers can order air ready masters to be created on-demand
- Improve automation and ingest through an automated backlot function
- Flexible Integration for Billing and existing system support. This is particularly key for existing processes that cannot be automated such as the creation of the local language text and foreign voicing of actors whose dubbing artist is already established in a territory
BPM & Orchestration
One of the key features of a modern MAM is the ability to Orchestrate a wide range of tasks using a Business Process Management engine (BPM). Manipulation of IMF structures needs an orchestrated solution. IMF requires a mix of metadata that can often be found in different databases. This metadata is often brought together at the last moment when an IMF composition is ingested or used to make a deliverable asset. Examples of the metadata are:
- Ownership information about the asset (usually in the MAM)
- Information about the tools creating the IMF (available at run time from the tools)
- Timeline information about the edit for the version (in the MAM or created by an editing tool)
- The end customer’s delivery specification (in a business database or order system)
- The language codes for the audio channels (in a delivery specification or a configuration preset)
- Identifier information (EIDRs, local MAM identifiers, destination MAM identifier – often provided job by job or in a MAM)
Figure 6 - A BPM engine with a graphical design interface allows triggers such as a file being ingested or a QC task being completed to start one or more pre-designed workflows where the IMF Supply Chain’s business rules control the overall flow.
Wide Downstream Format Support
Despite the strictness of the IMF structure, the real world of media distribution is still riddled with a wide variety of different codecs chosen by different media organizations for reasons that made good local sense at the time. This is where a BPM driven by a MAM that implements media-aware business rules becomes really important. Whether the media is Standard Definition, High Definition, Ultra High Definition at a frame rate of 24fps, 25fps or 29.97fps in an aspect ratio of 4:3. 16:9 or maybe even in 3D or VR, there will be a best way of processing the media for delivery.
The MAM is required to store rich, accurate, technical metadata about each piece of media. This rich metadata is then used to drive the workflows to know exactly what must happen in the next step for a particular customer. The solution of this classic “How do I get there from here” problem changes over time as different technical tools are invented or purchased to master the mathematical uncertainties of sub-Nyquist sampled media that need both smooth motion and high resolution to be viewed on today’s ultra-bright High Definition screens.
Even more importantly is that when that workflow is released into production, an IMF facility can onboard a new customer with similar requirements very quickly by cloning and then modifying an existing, reliable, MAM data-driven BPM workflow. This incremental approach to building workflow sophistication gives the IMF Supply Chain a significant advantage in their response time for onboarding customers in today’s sophisticated multi-platform world.
 SMPTE ST 2067 group of standards from the Society of Motion Picture and Television Engineers.
Bruce Devlin is standards vice president at SMPTE.
Other Bruce Devlin articles can be found by searching from The Broadcast Bridge home page for his name.
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