Back Page Identifying VBI Data

This is a signalling standard used by PBS for analogue TV Transmissions

(This needs expanding on)

PBS had an encoding box built by Soft Touch for all PBS stations to encode the time-of-day, call letters, and "network" onto line 21 field 2 (EDS/XDS info)

Example Data

FFmpeg & QCTools

CC_Decoder

As a very hacky and manual workaround, I managed to decode the PBS time by:

1. Loading the MKV into QCTools and enabling the EIA608 filter display.
2. Manually typing the relevant XDS Time bytes into a "fake" SCC file.
3. Converting the SCC file to human-readable "Closed Caption Disassembly" format using SCC Tools' CCASDI.

Input:

Scenarist_SCC V1.0

00:00:01:00    0701 D543 434C 4649 8FB3

00:00:02:00    0704 6880 8FFE

Command: ccasdi PBSTimeFakeSCC.scc

Output:

SCC_disassembly V1.2
CHANNEL 3

00:00:01:00    {XDS Ms TM 03:21S _SA Dec 03 1999 Fri \Cb3}
00:00:02:00    {XDS Ms TZ -16D \Cfe} 

"Hour in UTC (UTC is London's time zone--subtract four hours to get Eastern Time, eight hours to get Pacific Time; note that date and Day of Week are also UTC)" so I take it this is 19:21 PT on Dec 02 1999 Thu (the station is in WA).

Unfortunately the Local Time Zone field appears to be wrong. It's saying -16 daylight instead of -8 standard.

Closed Caption Disassembly Documentation: XDS Live / Archive

PBS XDS Google Groups

Brad MSGoham - DD86

https://github.com/CordySmith/cc_decoder

https://mediaarea.net/QCTools/Download

https://discordapp.com/channels/665557267189334046/687532251868823553/1065906289173082112

https://discordapp.com/channels/665557267189334046/687532251868823553/1066031886159327363

https://discordapp.com/channels/665557267189334046/687532251868823553/1066057549037699082

Example from drfsupercenter — 20/01/2023 18:12

XDS Channel Station Call-Sign:
XDS Current Scheduled Start Time: 21:00 on Day 30 of Month 09
XDS Current Program Name: VOTE 2004 PRESIDENTIAL DEBATES
XDS Rating: N/A
XDS Channel Name: ABC
XDS Channel Station Call-Sign:
XDS Current Length of Show: 02:00 XDS Current Elapsed time: 00:02:15

https://discordapp.com/channels/665557267189334046/687532251868823553/1066067285674037369

Back Page Identifying VBI Data