for interoperability in recipient systems . There was no new development in the design of the core IMF specifications ; the definitions that were designed and built for MXF still exist in the IMF specification , and the SMPTE committee made careful decisions not to use all features of MXF , but to focus the new specification only on those file specifications that supported media versioning and distribution . Interoperability was the key driving force for the analysis and inclusion in the design .
The IMF committee went further than the MXF group — It defined IMF as a new approach to media file organization and management , in other words a new way to think about the files that support better interoperability and version distribution . There are three key ideas that IMF introduces : Component Play Lists ( CPLs ), Output Play Lists ( OPLs ) and Identifiers .
• CPLs are an easy concept to grasp - a list of the integral parts comprising a particular asset , such as the video , audio and subtitles for a specific version .
• The OPL is a set of actions - the transformations that a CPL requires for a particular version , including format conversions , digital rights management , content delivery network preparations , etc . One CPL with an OPL defines an IMF complaint version of the asset .
• A truly important concept introduced by the IMF committee is the idea of Identifiers . IMF media is comprised of many identifiers , on many different levels , and they are used to build a particular composition for a CPL , or mark segments of media or specific events on a timeline in the media . These identifiers can act like pointers , and an IMF compliant file can identify multiple sources of media to be “ stitched ” together to form a new segment for a distribution requirement .
Simple content editing , splicing in advertisements or adding pre- or post-rolls is a simple assembly chore in an IMF compliant media preparation system . These identifiers provide tracking mechanisms on many layers , and tracking tools enable workflow automation , making the process of building interoperable versions automatic with all the benefits computerization offers , making operations faster , easier , more efficient and less labor intensive . This use of identifiers also enables new processes , such as sending identified linked components to change just a part of a previously delivered IMF file .
The benefits Broadcasters realize from a unified specification are fairly straightforward . The broadcast link in the media chain is downstream from the production and distribution operations , and as IMF package delivery becomes the norm , receiving an IMF file means that the broadcasters will have a significant reduction in the computing and transformations required in preparing media for playout on linear broadcast channels . Storing identified components and assembling them for re-use in different applications only when needed saves archive space . Studies by independent consulting firms estimate up to 27 % savings in labor , storage and computing processing , which translates into significant cost reductions .
And the IMF specifications are still evolving , including the establishment of new committees to uncover uses of OPLs , as well as the Internet Media Subtitling and Captioning Protocols ( IMSC1 ) specification which is a constrained modification of the Timed Text Markup Language ( TTML ) specification to support the rendering of subtitles or captions for any frame rate . All of these adaptations to the core specifications have the ability to make IMF more suitable and applicable to our global broadcasting community . The only concern facing Broadcasters is their specialized product vendors ; as the industry learned with the first MXF efforts , vendors attempt to leverage any subtleties in the specification to create unique selling positions for their products to capture a wider market share . To combat this opportunity for divergent compliance , SMPTE is hosting “ Plug Fests ,” a seminar comprised of vendors that will use their premiere products to create IMF files and packages and have them reviewed by a panel of SMPTE experts for specification compliance verification and certification .
Is IMF important for the Modern Broadcaster ? The answer is an unequivocal “ Yes !”
Does the IMF specification completely support all of our broadcasting needs ? Not yet .
The underlying standard and the core workflows
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