
GUIDE TO INSTALLATION AND OPERATION
XVP-1801 |
33
Flags
area
The Flags sub-section indicates which AFD flag is detected at the input and which flag is inserted at the
output.
The Active Format Descriptor (AFD) flag is used to identify the aspect ratio and protected areas of a video
signal. The XVP-1801 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 is sent in an ancillary packet, normally found on line 11 in the vertical ancillary space.
•
In SD, the AFD flag is sent as a VLI signal (RP 186) for 525 and 625 formats, as a WSS signal (ITU-R
BT.1119-2) for PAL only, and as an AFD packet (SMPTE 2016).
When AFD is present at the input, the card can perform an automatic adjustment of the aspect ratio. See the
appendix for more details.
Alternate ARC
area
When the output is 4:3 SD, if the input AFD setting is set to Auto or Forced mode and the input AFD is a full
screen 16:9 (AFD code 16:9_8), the output image may be scaled in one of 2 ways. Use the pulldown to
select which will be used:
•
Letterbox:
Uses the traditional 16:9 letter box within a 4:3 frame where there is no loss of image.
•
Center Cut:
The XVP-1801 provides a second alternative – the input is horizontally cropped about the
center to create a full screen 4:3 image. Choosing this alternative essentially removes 25% of the
original image.
The De-interlacer tab
Some interlaced video sources are film-based
originating from 24p film images. For optimum
scaling performance, it would be best to de-interlace
this type of source by simply merging the source’s
fields to recreate the original 24p image, thereby
introducing no de-interlacer artifacts prior to scaling
and format conversion.
Film mode:
When The Film Mode selection is set to
ON, the XVP-1801 monitors the input for film-based
sequences and applies the proper algorithm.
Film detection is provided for 3:2, 2:2 (59Hz and 50
Hz sources) and 5:5 sequences.
Video Over Film:
When the film mode is enabled,
turn ON the Video-Over-Film (VOF) function to
detect and bypass field-merging on certain video regions such as scrolling video characters over an entire
film frame, thereby preventing any unwanted combing effects.
Figure 3.15
Video Output group – deinterlacer tab