Page Comparison

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Derivative file locations can be found on the Fedora object's derivativeFile datastream by visiting: http://fedoraserver.example.edu/objects/{pid}/datastreams/derivativeFile/content

Configuring the Creation of File Location

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URLs

Master Files

Master files (the original, pre-transcoding, uploaded files) are stored in the path specified by the matterhorn.media_path key in config/avalon.yml, and (optionally) deleted or moved elsewhere after processing. The location of the master file is turned into a URL via the following steps:

1. Avalon grabs a list of mount points from the system and parses it, discarding everything that's not tagged as either smbfs, cifs, or nfs. (These are the only three remote file systems Avalon recognizes at the moment; we can add more if necessary.)
2. It then creates a hash of mount points to absolute prefixes (e.g., { '/var/avalon/masterfiles/' => 'nfs://some.server.northwestern.edu/masterfiles/' })
3. If the Avalon file location starts with any of the known mount points, the local mount point is stripped off the beginning and the rest is appended to the respective mount location. Otherwise, it just has file:// added to the beginning.

4. There's also an optional config file, config/mounts.yml, that can be used to override/add to the mount hash. So if the master files directory were actually accessible via HTTP somehow, you could set create the following config/mounts.yml:

   Code Block
   --- /var/avalon/masterfiles/: http://masterfiles.northwestern.edu/

   That would cause Avalon to link to the master file at /var/avalon/masterfiles/dropbox/my_collection/my_video.mp4 as http://masterfiles.northwestern.edu/dropbox/my_collection/my_video.mp4.

Derivatives

Derivatives (transcoded streaming files) are handled differently, since, unlike master files, there's no guarantee that the Avalon server has access to or knowledge of the locations where streaming content is stored. Instead of having to mirror Matterhorn's streaming configuration within Avalon, Avalon simply requests an avalon.stream_base property from Matterhorn. This property can be found in Matterhorn's etc/load/org.opencastproject.organization-mh_default_org.cfg file. By default, the property is a file:// URL prefix pointing to the directory where derivatives are stored:

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