Partial File Restore (PFR) transfer
Grass Valley servers are capable of performing a "Partial File Restore" (PFR) transfer. This allows you to specify only the material that you want transferred between two marks. For legacy reasons, the implementation has some quirks.
We insert only the material between the requested marks, BUT we leave the clip description in the GXF stream as it describes the original clips. That means, say a clip had marks 0 to 100 and you requested from 30 to 60, the clip description in the GXF would still indicate marks 0 to 100, but only media from 30 to 60 will exist in the GXF stream.
As a consequence, when you import this PFR GXF stream, you get a clip that has a duration (and marks) as the original clip. Depending on the requested marks, when you play the clip, you will have leading black, then requested material trailed by black. It is up to the user to then set the correct marks externally on the restored/imported clip using the protocols or the API.
To perform a PFR transfer, the option is specified in the source UML. So say you want to export fields 30 to 60 (30 inclusive, 60 exclusive – duration 30 fields) as a GXF file. Here are the UMLs:
Source UML: localhost/explodedFile/<clipname>?(30-60)
Destination UML: localhost/gxfFile/V:\temp\a-pfr.gxf
You can also do it using FTP:
ftp <host>
user: movie
bin
get <clipname>?(30-60) v:\temp\a-pfr.gxf // FTP creates the file a-pfr.gxf for you
quit
Caveats:
a) this works in this unusual manner for GXF; it must be this way for legacy support
b) this does not work for exporting MXF files
c) this works correctly for AVI and MOV exports; You get the “partial clip” with the correct duration
d) the material must already be recorded and on disk. You cannot specify a PFR for a clip that is under-construction where the material between the marks has not been recorded yet.
