Comcast is transitioning away from analog to digital. For those customers not upgrading to digital TV's, they are providing free digital to analog converters (DTA's). Traditionally, their full featured set top boxes (STB's) received all sorts of information such as encryption keys, guide data, etc via an out of band (OOB) POD interface. This is a special receiver that tunes frequencies outside of the normal TV frequencies. One of the pieces of information that's transmitted is a table that maps station callsigns and virtual channels (the integer channels that the STB's present to the user and are used by TV Guide, Schedules Direct, zap2it, etc) to RFchannel.program number that clearQAM TV's use. For example, Schedules Direct and Comcast may say FOODTV is channel 35 but a clearQAM capable TV plugged directly into the line will report it as 78.4. This would also traditionally require one to use the MythTV channel editor and manually input the frequency and program number for each channel and associate the xmltvid. Since Comcast is handing out DTA's for free, they are severely cost reduced and don't have a POD interface. In it's stead, they are transmitting the virtual channel table in-band (i.e. tuneable with a conventional clearQAM tuner) to allow the DTA's to do the virtual channel mapping.
scte65scan is a utility that will read the in-band virtual channel tables and automate the mapping of frequencies and program numbers to virtual channels and xmltvids.
A quick overview of the process is as follows:
- Find the VCT_ID for your lineup. This can be done by obtaining a DTA or STB and reading it from the diagnostic page. Alternatively, it can also sometimes be found by inspection through an examination of the text-mode output of scte65scan
- Generate SQL for importing into MythTV (e.g. 'scte65scan -f3 -V your_VCT_ID itfile > vct.sql')
- Import the SQL into MythTV (e.g. 'mysql mythconverg < vct.sql')
For more information, visit the scte65scan project page