Handling “wrapper” file formats

The transform file <transformFile> element provides a means to access any subsidiary files listed below a <file> element by indicating the steps required to unpack or transform the subsidiary files, such as decompressing, decrypting, or unpacking files. This element is repeatable.

Example

The following example describes a *.tar.gz file which has two embedded files within it, one a TIFF file and the other a JPEG file of the same image. To use the <fileSec> to describe these files, you could use the <transformFile> element in the following way:

<mets:fileSec ID="TransformEX_01">
  <mets:fileGrp ID="TAR_GZ_example" USE="Container">
    <mets:file ID="TAR_GZ_container_01" MIMETYPE="application/tar.gz" USE="Container">
      <mets:FLocat LOCREF="file://sample01.tar.gz" ID="sampleTar01.gz" LOCTYPE="URL"/>
      <mets:transformFile TRANSFORMORDER="1" TRANSFORMTYPE="decompression" TRANSFORMALGORITHM="gunzip"/>
      <mets:transformFile TRANSFORMORDER="2" TRANSFORMTYPE="decompression" TRANSFORMALGORITHM="tar"/>
    </mets:file>

    <mets:file ID="file_01" SEQ="1" MIMETYPE="image/tiff" CHECKSUM="c1b82611e48066016ceb8daa93d46de7" CHECKSUMTYPE="MD5">
      <mets:FLocat LOCREF="file://sample01_image01.tiff" LOCTYPE="URL" USE="Archival Master"/>
    </mets:file>
    <mets:file ID="file_02" SEQ="2" MIMETYPE="image/jpeg" CHECKSUM="c3cb82611e48066016ceb8daa93d46df5" CHECKSUMTYPE="MD5">
      <mets:FLocat LOCREF="file://sample01_image01.jpeg" LOCTYPE="URL" USE="Display Derivative"/>
    </mets:file>
  </mets:fileGrp>
</mets:fileSec>