Technical SpecificationsClosed CaptioningMakito X User’s Guide, v2.0, Issue 01 389NOTE The extracted CC information from Line 21 is embedded in the MPEG stream asper ATSC A/72 Part 1:2008 (ATSC A/53 Part 4:2007).Unicast and Multicast streams all carry the same CC data.The Makito X encoder supports the capture of EIA-608 and EIA-708 closed captions fromthe video input at the HD/SD SDI interface and encodes it in the Makito X TransportStream using the encapsulation format specified in ATSC A/72.The Makito X encoder supports the capture of EIA-608 and EIA-708 captions encapsulatedin a Caption Description Packet (CDP), as described in SMPTE-334-2, within the VANCas mentioned in SMPTE 334-1. The Caption information is multiplex and transported asper ATSC A/72 in a CC SEI NAL. The caption services stored in the Caption ServiceDescriptor (CSD) are announced in the Program Map table (PMT) of the MPEG-2 TS asper ATSC A/65.NOTE The Makito X only supports a maximum of three (3) Caption active services at atime plus CC1-4 Text1-4 and XDS.SMPTE 334-2 defines a Caption Distribution Packet (CDP) consisting of a sequence ofbytes that can hold: the CEA-708 DTV caption data, CEA-608 caption data, captionservice information, and SMPTE 12M-1 time code. CDP also includes the Caption ServiceDescriptor (CSD). As defined in ATSC A/65.With the support of EIA-708, ATSC A/72 mandates a dedicated link bitrate of 9600bits/sec. (1200 bytes/sec or 20 bytes per frame for a p60 SDI signal). Of the 9600 bits/sec,960 bits/sec are reserved for EIA-608 captions. 8640 bits/s are dedicated to 708-CC. Thisis a dedicated channel, so it has to be filled with filler data if no captioning information ispresent.Supported resolutions include 1080p, 720p, 1080i, 480i, and 576i.
