GUIDE TO INSTALLATION AND OPERATION
56
| XVP-3901
teletext data from the incoming OP-467 packets. The actual assignment of data to these lines is determined by
the mode selected in the
Insertion Mode
pulldown.
The
Insertion Mode
pulldown offers two modes of operation:
•
Auto – Teletext data will be inserted on the enabled lines, represented by the
SD Output Teletext Insertion
Lines
checkboxes, only if incoming OP-47 packets carry teletext data targeted for these lines
•
Bulk – the teletext will be inserted in the lines selected in the checkboxes above the pulldown, in the order of
arrival (first line detected in incoming OP-47 packets is inserted in the first line checked, etc). If there are more
incoming lines than lines selected, the extra lines will be lost. If there are fewer incoming lines than lines
selected, the extra selected lines will not carry any teletext. For example, if Lines 9, 11, and 14 are selected
and presence indicators 15, 16, 19, and 20 are turned on, then detected OP-47 packets with embedded data
from lines 15, 16, and 19 will be inserted on SD output lines 9, 11, and 14 respectively. The data from line 20
will be lost.
SD inputs
– incoming teletext is passed through to the output as received; the lines cannot be changed (Pass mode).
•
The
Incoming Teletext Presence
indicators 7 to 22 indicate the SD lines where teletext data, conforming to
ETSI EN 300 706, has been detected.
•
The
SD Output Teletext Insertion Lines
checkboxes are active, and can be configured so as to be ready when
the input is switched to an HD source. They have no effect on an SD source..
Current Mode
– this databox displays the current operating mode – AUTO, BULK or PASS
5.5.5 SD Output – AFD tab
The Active Format Descriptor (AFD) flag is used to identify
the aspect ratio and protected areas of a video signal. The
XVP-3901 uses this flag in some cases to adjust the output
aspect ratio and image cropping to obtain the best possible
presentation of the image. The AFD flag is implemented
differently in SD and HD:
•
In HD, the AFD flag (SMPTE 2016) is sent in an ancillary
packet, normally found on line 11 in the vertical ancillary
space.
•
In SD, the AFD flag may be sent as a VLI signal (RP 186),
as a WSS signal (ITU-R BT.1119-2) for PAL only, and as
an AFD packet (SMPTE 2016).
When an AFD flag is present at the input, the card can
perform an automatic adjustment of the aspect ratio. See the
appendix for more details.
5.5.5.1 Default settings section
Default/Forced:
this text box is labeled according to the
mode selected in the Input Screen pulldown in the Video
Output Group – see page 42.
•
In AUTO mode, labeled DEFAULT and shows the current default AFD code to be used if no valid AFD code is
detected at the input.
•
In FORCED mode, labeled FORCED, and shows the code that is forced into the system input regardless of the
actual input code.
•
In 4:3 (SD input) or 16:9 modes, the data box is empty and the controls are grey. In these modes, ARC settings
can be manually set using the ARC tab controls.
Figure 5.36 Video Outputs SD - AFD tab