Metadata tags

The metatags.xml file can be used to customize how metadata is read from media files. An example file showing the supported tags, including reading position and orientation metadata from drones, is included with PFTrack and is available in application installation folder: media/metatags.xml

This file contains a list of metadata tag names, collected into a hierarchy, such as:

<?xml version="1.0" encoding="utf-8"?>
<metatags>
  <photo>
    <body>
      <make>Exif.Image.Make</make>
      <model>Exif.Image.Model</model>
      <serial>Exif.Photo.BodySerialNumber</serial>
      ...
    </body>
  </photo>
</metatags>

In this example, the metadata tag Exif.Image.Make is used to define the camera body make for photogrammetry, Exif.Image.Model defines the camera body model, and Exif.Photo.BodySerialNumber contains the camera body serial number.

For example, this illustrates how to read camera focal length from the tag Exr.myApplication.FocalLength:

<?xml version="1.0" encoding="utf-8"?>
<metatags>
  <movie>
    <lens>
      <focal>Exr.myApplication.FocalLength</focal>
    </lens>
  </movie>
</metatags>

You can also read frame rates from movie clips by adding a frameRate entry to the movie information containing the metadata tag you wish to use:

<?xml version="1.0" encoding="utf-8"?>
<metatags>
  <movie>
    <body>
      <frameRate>Exr.framesPerSecond</frameRate>
    </body>
  </movie>
</metatags>

You can place an additional file in metatags.xml containing any user-specific changes to avoid the need to edit the file installed alongside PFTrack.

Further information about different types of metadata and how it can help your production is available in the Why Metadata Matters in Modern Matchmoving article.