Grass Valley Channel Composer v.1.6.2 - Manual (Page 57)

Channel Composer User Manual - Channel Composer User Manual- document version: 1.6.2 - 56
7.4 Subtitles
Channel Composer supports the following subtitle output formats:
• In-Vision subtitling
• DVB subtitling
• Teletext subtitling
• Closed Captioning subtitling
7.4.1 Introduction
Channel Composer supports the following subtitle output formats:
•
In-Vision subtitling
The open In-Vision format produces subtitles as graphical images that are made permanently
visible on screen. They cannot be switched off. Due to the graphical nature of this format, a large
set of unicode characters are supported. Using the grid (described below), placement of subtitles on
screen can be controlled. Using the Object Properties tab in Channel Composer, the font style can
be controlled.
• DVB subtitling
The closed DVB-subtitling format produces graphical images that are encoded and inserted into
an MPEG-transport stream and identified with given PID. These subtitles can be displayed
(optionally) on set top boxes or TV-sets that support the DVB-format. This format too supports a
wide array of unicode characters due to its graphical nature. The grid and font style options
available for the In-Vision format apply here as well.
• Teletext subtitling
Closed Teletext subtitling is a character based protocol originally developed for the PAL
broadcast format. Subtitles are added to the broadcast signal. Subtitles can be shown (optionally)
on screen on TV-sets that support the Teletext protocol. The grid and font style editing features
do not apply.
• Closed Captioning subtitling
Closed Caption subtitles are similar in nature to Teletext subtitles. It is a character based protocol
originally developed for the NTSC broadcast format. Subtitles are added to the broadcast signal.
Subtitles can be shown (optionally) on suitable TV-sets. The character set is relatively limited.
The grid and font style editing features do not apply.