For standard definition (SD) VBI insertion,
InFilePS works
in a similar way to a hardware SDI inserter except that it works on a file instead of
an SDI signal.
For each subtitle (caption) in the source STL or CAP file,
InFilePS converts
the text and control characters to a luminance signal that is inserted into designated video
lines in the vertical blanking interval, following the WST (World System Teletext) or Line 21 (USA) specifications.
InFilePS can generate a lower-resolution preview (proxy) in either MPEG-1 or MPEG-2
(DVD quality) which shows the captions "burnt-in". The result is intended to be as close as possible
to what the viewer will see with closed captions turned on in their receiver.
For high definition (HD) insertion,
InFilePS utilises standards EIA-708 (incl.
backwards compatible EIA-608 mode) and ancillary data insertion according to the specific requirements
of the target video file format.
InFilePS also supports high quality open caption insertion for both SD and HD content
through the use of pre-rendered captions. These are typically generated using the TrueType rendering
output from
SysMedia WinCAPS.