Line 21 Close Caption Encoder
CC EIA 608 closed caption is inserted in line 21 in field 1 of the VBI. Close Caption (CC) is generated at a regular computer with windows operating system using a CC software package. Some of the options are paint text on, roll text up or down, select location where text will be displayed on the screen and text size. This format is used with analog NTSC.
Digital CC EIA 708 used with the digital channels has more options. A Choice of fonts, color and size with a choice background and foreground color are available. The data is inserted in line 9 service 1. This format is used with HDSDI and SDI, SMPTE 292 and 259 respectively.
CC for live broadcasts is created by a court reporter located off studio and connects via modem. They use a court reporter system that sends ASCII text through the telephone lines.
EIA 608 is the data standard for CC for NTSC.
EIA 708 608 is the data standard for CC for Digital TV.
Service 2 of line 21 has future use of interactive TV. ATVEF
Transport A (ATVEF-A) delivers content triggers via the Line 21 closed caption
channel and delivers content via the Internet.
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