Grass Valley K2 Media Client User Manual v3.3 - Manual (Page 263)

June 5, 2009 K2 Media Client User Manual 263
Active Format Description (AFD) specifications
Active Format Description (AFD) specifications
NOTE: This topic only applies to SD and HD channels on K2 Media Clients and
K2 Summit Production Clients.
Active Format Description (AFD) can be used to automatically determine the proper
aspect ratio to use for up- and down-conversions. Previous versions of the K2 Media
Client let you set the aspect ratio conversion (ARC) on a clip-by-clip basis or per
channel. Now, you can use the AFD code to set the aspect ratio of the clip and the
ARC performed. If no AFD is set, the ARC setting operates as it did in previous
versions of the K2 software. For more information about ARC settings, see
“Playout
of multiple formats” on page 259 .
About Active Format Description
The AFD is defined during production. By inserting metadata about the aspect ratio
into the vertical ancillary data, AFD can define the aspect ratio of the signal as it
progresses through ingest, editing, up/down conversion and playout. If the aspect
ratio is altered during processing, then the AFD passed on downstream might need to
be modified to ensure the correct aspect ratio is obtained.
NOTE: If ARC leads to unsupported active video format (postage stamp), the new
AFD code will be the ‘undefined’ value of 0000.
The playback aspect ratio conversion is prioritized according to the following
table:
To see the full list of AFD input/output settings, refer to “AFD input/output settings”
on page 264 .
NOTE: Bar data is not supported on the K2 system.
Storing AFD in the K2 Media Client
The K2 Media Client stores clip metadata in clip properties and uses this data
throughout the workflow. Users can modify the AFD setting in AppCenter. For more
information on applying AFD settings in the UI, see
“Applying AFD settings” on
page 240 .
You can store AFD in a data track. Grass Valley recommends selecting this for HD
clips; if using SD, this is optional. This method takes more storage (it is approximately
equal to four tracks of audio) but this method enables AFD and CC/Teletext support
for HD.
Playback aspect ratio conversion priority
1 Clip property (ARC or AFD-based conversion rules)
2 Output channel (ARC configuration property)