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##MediaTrace Data Dictionary

Introduction

The MediaTrace Data Dictionary offers documentation and definitions for the MediaTrace XML format. MediaTrace XML is a document which itemizes and describes parts of a digital file in a way that allows for a highly comprehensive index of a file. MediaTrace XML is supported as an export document by MediaArea utilities, particularly MediaInfo and MediaConch.

Most digital container formats are comprised of elemental blocks; MediaTrace XML is intended as a document representation of that elemental structure to show the hierarchical relationship, size, labelling, and contents of each block.

MediaTraceXML will document values of elemental contents such as text strings, short binary values, numbers, and dates. For container elements that contain binary data (such as the audiovisual payload of a media file, for example), MediaTrace will document only the size, and no the contents of the payload itself.

MediaTrace XML is not intended to fully categorize and sumamrize the significant properties of a digital file, but instead focuses on comprehensively documenting the file structure as a whole, with consideration to the depth possible by MediaInfoLib's file parsers.

Additional Resources

Documentation about the MediaTrace format is available at its namespace, https://mediaarea.net/mediatrace/. The XML Schema is available at https://mediaarea.net/mediatrace/mediatrace.xsd. The development history and issue tracker for MediaTrace are available at GitHub.

Credits

Developed by MediaArea in collaboration with the Museum of Modern Art.

Data Model

The data model of MediaTrace XML is comprised of several flexible and generic elements to support methods for documenting highly diverse sets of digital media. The MediaTrace Schema contains only three elements: MediaTrace, block, and data. The MediaTrace element provides the root level element of the document and contains only block elements. The block element documents a structural piece or elemental component of a digital file's bitstream. The block may then contain either other block elements or data elements. The data elements document the lowest-level and most granular aspect of the file's contents. Both block and data elements share an attribute set which contextualizes the information with byte offsets, additional information, and labelling.

Semantics

Element MediaTrace
Definition MediaTrace is the root-element of the XML document and contains a structural report of a digital file comprised of logically arranged block and data elements.
Examples See MediaTrace's GitHub repository for example MediaTrace XML documents.
Repeatability Not repeatable
Obligation Required
Attribute ref
Definition The ref attribute identifies the path of the file from the root directory.
Is Attribute Of MediaTrace
Examples /Users/mediaconch/ffv1_0.mkv
Repeatability Not repeatable
Obligation Optional
Attribute version
Definition The version declares the release number of MediaInfoLib.
Is Attribute Of MediaTrace
Examples 0.7.74
Repeatability Not repeatable
Obligation Optional
Element creatingApplication
Definition The creatingApplication element identifies the application used to produce the MediaTrace document.
Examples MediaInfo
Repeatability Not repeatable
Obligation Optional
Element creatingLibrary
Definition The creatingLibrary element identifies the library used with the associated application.
Examples MediaInfoLib
Repeatbility Not repeatable
Obligation Optional
Attribute version
Definition The version attribute specifies the version of the creating application or library.
Is Attribute Of creatingApplication, creatingLibrary
Examples 0.7.76
Repeatbility Not repeatable
Obligation Required
Attribute url
Definition The url attribute provides the uniform resource locator, i.e. web address for the creating application or library.
Is Attribute Of creatingApplication, creatingLibrary
Examples https://mediaarea.net/MediaInfo
Repeatbility Not repeatable
Obligation Optional
Attribute build_date
Definition The build_date attribute specifies the date in which the creating application binary was built, as a string in ISO 8601 YYYY-MM-DD format.
Is Attribute Of creatingApplication, creatingLibrary
Examples 2014-09-13
Repeatbility Not repeatable
Obligation Optional
Attribute build_time
Definition The build_time attribute specifies the date in which the creating application binary was built, as a string in ISO 8601 HH:MM:SSZ format.
Is Attribute Of creatingApplication, creatingLibrary
Examples T12:42:45+0200
Repeatbility Not repeatable
Obligation Optional
Attribute compiler_ident
Definition The compiler_ident attribute identifies the compiler used with the creating application or library.
Is Attribute Of creatingApplication, creatingLibrary
Examples Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn)
Repeatbility Not repeatable
Obligation Optional
Element block
Definition The block element documents a structural piece or elemental component of a digital file's bitstream. The block may then contain either other block elements and/or data elements.
Examples <block offset='719' name='Flags' size='1'>
               | `    <data offset='726' name='KeyFrame'>1</data>`
               | `    <data offset='723' name='Reserved'>0</data>`
               | `    <data offset='722' name='Invisible'>0</data>`
               | `    <data offset='720' name='Lacing'>0</data>`
               | `    <data offset='719' name='Discardable'>0</data>`
               | `</block>`

Repeatability | Repeatable Obligation | Optional Usage Notes | Many audiovisual formats are based on chunk-based storage in which a block of data will contain either a data payload or other blocks. In QuickTime parlance, these blocks are called 'atoms'; in AVI 'chunks', and in Matroska, 'elements'. MediaTrace will attempt to parse apart each block into subdivisions and report on their contents. Whether the source format specification calls it element, atom, chunk, or another term, MediaTrace will call it a block.

Element data
Definition The data elements document the lowest-level and most granular aspect of the file's contents.
Examples <data offset='552' name='Data'>Lavf56.40.101</data>
Repeatability Repeatable
Obligation Optional
Attribute offset
Definition The offset is an integer that expresses the location of the data or block within a digital file relative to the start of the file, measured in octets.
Is Attribute Of data, block
Examples 0, 1000, 298346234
Repeatability Not repeatable
Obligation Optional
Attribute name
Definition The name attribute stores a label associated with the block or data. The name may provide a human-readable label as gathered from the file format's associated specification or the name may provide an unprocessed identifier as used internally within the file's structure.
Is Attribute Of data, block
Examples TimecodeScale
Repeatability Not repeatable
Obligation Optional
Attribute info
Definition The info attribute stores values that have been gathered or interpretted from the block or data by MediaInfo's file parsers.
Is Attribute Of data, block
Examples <block offset="39" name="DocTypeVersion" info="4" size="4">
Repeatability Not repeatable
Obligation Optional
Attribute info2
Definition Same as info but provides additional contextual information.
Is Attribute Of data, block
Examples <block offset="119" name="SeekPosition" info="108807" info2="1A942" size="6">
Repeatability Not repeatable
Obligation Optional
Attribute info3
Definition Same as info but provides additional contextual information
Is Attribute Of data, block
Examples
Repeatability Not repeatable
Obligation Optional
Attribute info4
Definition Same as info but provides additional contextual information
Is Attribute Of data, block
Examples
Repeatability Not repeatable
Obligation Optional
Attribute info5
Definition Same as info but provides additional contextual information
Is Attribute Of data, block
Examples
Repeatability Not repeatable
Obligation Optional
Attribute info6
Definition Same as info but provides additional contextual information
Is Attribute Of data, block
Examples
Repeatability Not repeatable
Obligation Optional
Attribute info7
Definition Same as info but provides additional contextual information
Is Attribute Of data, block
Examples
Repeatability Not repeatable
Obligation Optional
Attribute info8
Definition Same as info but provides additional contextual information
Is Attribute Of data, block
Examples
Repeatability Not repeatable
Obligation Optional
Attribute size
Definition The size is an integer that expresses the amount of data being described by the data or block element measured in octets.
Is Attribute Of data, block
Examples <block offset="410" name="CodecID" info="V_MS/VFW/FOURCC" size="17">
Repeatability Not repeatable
Obligation Optional