An Explanation of IMF Import Support in Vidispine Server pt2

By Isak - January 17, 2018

We added support for IMF in Vidispine Server 4.7. Now, with version 4.12, we have improved import, modification and export of IMF packages. Read about the enhancements released in 4.12 and get a preview of what’s coming in 4.13.

Vidispine Server version 4.7 introduced support for IMF packages (IMP) that were already uploaded and discovered on a Vidispine storage. This type of import requires that you already know the file id of the asset map and that all of the other files have been discovered (assigned file ids) by Vidispine. The import creates a new item with a shape pointing to the various files. The shape can be modified and transcoded to other formats, but that will not update the Asset Map or CPL. When exporting, the original Asset Map, PKL, CPL are written.

IMF in 4.7

4.12 IMF Support

The new model is using Vidispine Storage as a central repository based for the media resources based on the UUID of the resource. Thus, Vidispine Server has knowledge of all resources and can quickly import new versions without unnecessary transfers.

Import

The new API call /API/import/imp imports an asset map given a URI. The asset map is analyzed and referenced material is transferred to Vidispine Storage. The shape created will contain the metadata contained in the CPL. The XML integrity of the IMP is validated on import in version 4.12.

New IMF import model

The example below shows an import of another asset map which partly uses the same content as the previous IMP. Note that the video resource is not copied, it is simply linked to the file already existing.

IMF import with partly the same content

Import also supports asset maps that contain multiple CPLs. In that case, one Item is created with multiple Shapes. In the example below, two video resources are referenced by one CPL in a sequence.

IMF import with multiple CPLs

Finally, import can also be done to an existing item, thus creating new shapes for the item.

When importing a new CPL (to an existing item), a new shape is created. If the shape has a shape tag (by default it will have the “original” shape tag), the new shape will have a new essence version. IMF shapes can be transcoded as any other Vidispine shape since the transcoding process recognizes intervals and shapes. It’s also possible to create IMF shapes without having IMF content as the transcoder can generate MXF files.

IMF Virtual Track Metadata

Metadata stored in the CPL referring tracks are stored in the shape metadata, with the new key syntax: {track}/{key}, such as /item/{item-id}/shape/{shape-id}/metadata/A0/imf_trackid.

Altering composition playlists

The already existing methods for modifying components, and moving them between shapes, can be used to modify items/shapes that were created as a result of import. In fact, there is no difference between an “IMF Item” and any other Item. That means that you can create an Item from scratch without importing anything, and then associate components to it.

Export

When exporting, the asset map, PKL, and CPLs are recreated from the current shape information, using the new API call /API/item/{id}/export/imp. Export can be done of sets of shapes. When exporting, metadata from the shape is exported as well. When exporting, specific tracks can be selected.

Differences between new and old method

You can continue using IMPs that was imported using the old method as-is, including export using the new export method. However, IMF metadata contained in the old item will not be exported.

  • Partial resources: The new method allows referencing partial resources, with the interval adjusted using API calls.
  • Segments: The new method support segments, including creating segments after the import of an existing shape.

IMF support sneak preview

The integrity of the CPL is validated during import in version 4.12, and validation of the MXF ids as well will be available in 4.13.

IMPs that contains a CPL pointing to media that are not part of the package, and not yet present in Vidispines since previous imports, will fail the import in version 4.12. In 4.13, the media will be imported and added to placeholder components which are completed when the media arrive.

Vidispine Server does not support using IMF shapes in Vidispine Sequences yet.

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