24757 MXF White Paper v2

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As said earlier, Pro-MPEG forum and AAF associationmembers agreed to develop MXF as a subset of AAF.The AAF file format has been developed for highperformance authoring applications, including non-linearediting and multi-layer compositional work. Thisrelationship is shown in Fig. 4.AAF allows for a very flexible description of its contentsand specifies all edit processes during a non-destructiveedit operation. This description can include all EDL-like(Edit Decision List) information, special effects and variouselements of rich meta-data. While AAF offers a highlevel of versatility and performance for authoringwork, it is, however, too flexible and rich for the purposeof file interchange. If AAF files are exchanged, numerousconstraints are required for file interoperability. Therefore,from an AAF viewpoint, a simpler version of AAF(i.e. with limited functionalities and specific exchangecharacteristics) is required for file interchange. MXF issuitable for this purpose.On the other hand, MXF is a new format in the industry,requiring a relation to an existing format. AAF is the onlyavailable file format with capabilities to handle richmeta-data. Therefore, MXF has been developed as a subsetof the AAF format - just like a light version of AAF.MXF allows the description of an editing operation for acut edit only, but it cannot specify complex special effects.In MXF the sequence of body contents is placed in thepresentation order. This comes from the requiredfunctionality of streaming of the file contents oversynchronous stream interconnections. During thestandardization process, the EBU requested the inclusionof specific meta-data for use by broadcasters, which isknown as “Geneva Scheme meta-data.” While thismeta-data is very useful for broadcast operations, thecurrent specification of AAF does not include it. However,since AAF is a very flexible and expandable file format,it is expected that the Geneva Scheme for meta-datawill be adopted by AAF in future revisions of the format.Fig. 4 Relationship between AAF and MXF
The Geneva Scheme meta-data is specified in part 4of the MXF documents. The purpose of this scheme formeta-data is to add content descriptions scene by scene.This document is simply a collection of various types ofexisting meta-data. For example, the Location information,Language information, Image formats, Scriptingdescriptions, Contracts and Rights, Sub-title descriptions,Owner information, etc. This document will become adynamic standard, which means it will be expanded infunctionality by future revisions of its meta-data set.The Geneva Scheme meta-data is the first step for theglobal exchange of meta-data for contents description.The Geneva Scheme meta-data is therefore a keyadvantage for the use of MXF file format.Both AAF and MXF are file formats, but theirfunctionalities do not conflict with each other.AAF is a very flexible format that is suitable forcomplex edit operations; it is, however, verydifficult to exchange AAF files between differentmanufacturers’ devices. Therefore, an acceptablestandard file format is necessary for the exchangeand archive of program materials. This concept isspecified in Fig. 5. MXF is a file format specificallydesigned for simple exchange and archive of final,complete, material packages.Fig. 5 The relationship of AAF and MXF format
Page 2 and 3: This paper describes the implementa
Page 4 and 5: MXF has been defined as a flexible
Page 8 and 9: Different types of file formats are
Page 10 and 11: MXF can contain meta-data in the he
Page 12 and 13: According to our model for an IT-ba
Page 14 and 15: The MXF format is defined as a wrap
Page 16 and 17: The EBU PITV group has started the
Page 18: Sony Electronics Inc.1 Sony DrivePa

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