Ross Opengear UDC-8625A Series, User Manual, Page: 75 / 174

UDC-8625A Series User Manual (Iss. 11) Ancillary Data • 5–7
CEA-708/CEA-608 Closed Captioning
When disabled, closed captioning (packet and line 21) is not inserted. Otherwise, this section
summarizes the closed caption processing of the card.
The UDC-8625A series card:
• ensures continuity of CEA-608 data and/or DTVCC data during frame drop or repeat.
• receives the packet, processes it, and inserts a new packet into the specific line.
• monitors the CDP sequence number of incoming CEA-708 data to detect discontinuities
in the DTVCC transport stream, and propagates any sequence-number discontinuity to
the outgoing DTVCC data, to alert downstream equipment of the change.
Note that Line 21 may also be treated as part of the input picture, depending on how the Blank #
Active Lines setting is configured in the Video tab of DashBoard.
Captioning Priority
There are three supported types of closed captioning data: native CEA-708, CEA-608 embedded
in CEA-708, and CEA-608 from Line 21 (480i inputs only).The order of preference for output
CEA-708 data is as follows:
1. CEA-708
2. Up-converted CEA-608 embedded in CEA-708
3. Up-converted CEA-608 from Line 21
4. Null content
The order of preference for output CEA-608 data is as follows:
1. CEA-608 embedded in CEA-708
2. CEA-608 from Line 21
3. Null content
Note that CEA-708 is not down-converted to CEA-608.
The card decodes any CEA-708 caption distribution packets (CDP) from the input video and
embeds the same data in the output video. The CDP is re-formatted as required based on the
frame rate, to maintain the correct CEA-708 transport channel data rate (9600bps) as specified by
SMPTE 334-2. The UDC-8625A series card removes any timecode information in the CDP. If
there is no native CEA-708, then CEA-608 is translated to native CEA-708 DTVCC format, and
embedded along with the original CEA-608 data in the output CDPs.
• CC1 is translated and encoded as DTVCC Service #1.
• CC3 is translated and encoded as DTVCC Service #2.
• CC2 and CC4 are not translated.
• such translation follows
CEA-708-C section 8.11 and supports the standard character sets
described in CEA-608-D section 6.4.1 .