Grass Valley iTX System v.2.6 - Manual (Page 260)

The Media Cache Service
The Media Cache Service responds to TXPlay cache requests in one of two ways, depending on
whether or not there is already a copy of the required file in the cache:
• If there is a copy of a required file in the Output Server cache, the Media Cache Service
compares this with the original version in the specified location. If the two files are the
same, no caching operation is needed. The Media Cache Service reports this to TXPlay.
In the Schedule Grid, the specified file location is the cache; the cache-status indicator
appears with a green light [  ].
• If there is no copy of the required file in the Output Server cache, or if there is a copy
but it does not match the original version, caching is required. The process differs
slightly, depending on whether the location of the original file is an iTX Media Store or
a search folder (e.g. for an archive). There is also a slightly different process for a file
that is being ingested by an iTX Encoder.
Caching from an iTX Media Store
When the Media Cache Service starts caching a media file from an ITX Media Store, the cache-
status indicator for the event shows orange [  ].
The Media Cache Service ensures there is enough space in the cache (see below, "Cache
management"). It then uses the Output Server to copy the media file to the cache; the Output
Server controls the copy rate.
When the media file is in the cache, the Media Cache Service notifies TXPlay. This updates the
event in the Schedule Grid to show the cache as the file location; the cache-status indicator
turns green [  ].
Caching from a search folder
When the Media Cache Service starts caching a media file from a search folder, the cache-
status indicator for the event shows orange [  ] if iTX can play out the file from the search
folder; it shows blue [  ], instead, if the search folder is an archive.
To copy media files from a search folder, the Media Cache Service uses the Media Watcher; this
must be set up to access the search folder. Depending on how it is configured for this, the
Media Watcher copies the media file to one of two places:
• An iTX Media Store, if the Copy media to central store option is selected in the
configuration of the search folder.
The Media Cache Service then manages the copying from the Media Store to the
cache.
• Direct to the Output Server cache, if the Copy media to central store option is not
selected. The Media Cache Service notes when the file is in the cache.
When the media file is in the cache, the Media Cache Service notifies TXPlay. This updates the
event in the Schedule Grid to show the cache as the file location; the cache-status indicator
turns green [  ].
Caching a file that is being ingested
When the Media Cache Service prepares to cache a media file that is being recorded by an iTX
Encode Server, the cache-status indicator for the event shows blue [  ]. Once the file is on the
Media Store, the Media Cache Service caches it; the cache-status indicator first turns orange
[  ], and then green [  ].
March 2015 System Administrator Guide Page 260 of 404