[mythtv] Adding PLP support (DTV_STREAM_ID)

[Torbjorn Jansson]

Hello.

i have a few questions but first some background.

several years ago i bought a usb based dvbt2 tuner with the intention to 
replace my pcie card.
i picked a TT CT2-4650 since it was supposed to have linux support already.
turned out that was not true since i got a newer version of it with no linux 
support, so with a bit of hacking on the drivers i was able to get it working 
due to the similarities with other cards.

but i quickly realized i could not tune to any dvb-t2 mux, after a lot of 
troubleshooting i gave up and forgot about it.

then a year or so later my dvb tv box broke down and i bought a new one (vu+ 
solo4k) and to my surprise it had the exact same issue.
after even more troubleshooting i found out i need to set PLP ID to 1 for 
tuning to work on dvb-t2 muxes.

so then i realized that must be the same problem with my ct2-4650 and it was.
yesterday i got tvheadend working on the usb tuner successfully and thats the 
first time i got the usb tuner to do something useful.

BUT channel scanning is not working, so mux must be setup manualy, that 
includes PLP ID and other paramters.
so i think the drivers don't do auto detect like my pcie card does.
and the downside of missing autodetect of plp is that most software dont know 
how to handle plp and this applies to mythtv too.



so for mythtv to work with this card i need to convince the backend to specify 
plp when tuning.
so a new mux paramter need to be added to database and then used during tuning.
as i understand it this is done with a property called: DTV_STREAM_ID and i 
need to try to understand better how libs/libmythtv/recorders/dvbchannel.cpp works.

can someone give me any pointers about this?
to start with i'm happy with a proof of concept hack that sets DTV_STREAM_ID to 
1 on all dvb-t2 tuning attempts, then if it works i can try and get a proper 
patch for it.

i probably wont be able to get the mux editor or settings working since i'm not 
familiar with how the setup gui works.
but if i get a new optional mux setting for plp in place then i'm happy.