In television technology, Active Format Description (AFD) is a standard set of codes that can be sent in the MPEG video stream or in the baseband SDI video signal that carries information about their aspect ratio and active picture characteristics. It has been used by television broadcasters to enable both 4:3 and 16:9 television sets to optimally present pictures transmitted in either format. It has also been used by broadcasters to dynamically control how down-conversion equipment formats widescreen 16:9 pictures for 4:3 displays.
To change the AFD on the Harmonic system follow these steps.
On the Harmonic Manager machine (192.168.1.155 and physically in the ECR room) activate the Monitor window
The Window looks like this:
Press Alt+P to activate the playertest terminal screen. From the > prompt type the following command:
darc FILENAME (AFD) see below for more information.
AFD Basics:
4:3 Streteched Image: Full Frame in 16:9 frame, Pillarbox in 16:9 frame.
TO 
= AFD{8.0 (1000/0),9.0(1001/0),d.0(1101/0)]} DARC FILENAME Pillar
16:9 Image(anamorphic SD): Anamorphic in 4:3 frame, Full Frame in 16:9 frame.
to 
= AFD{ 8.1(1000/1),9.1(1001/1)} DARC FILENAME Anamorphic
16:9 Image: Full Frame in 16:9 frame, Letterbox in 4:3 frame
TO 
= AFD{ 8.1(1000/1),a.1(1010/1) } DARC filename Letter
4:3 Image: Full Frame in 4:3 frame, Pillarbox in 16:9 frame.
TO = 
AFD{ 9.1(1001/1) } DARC filename Full