[mythtv] OpenTV logical channel numbers

[Stephen Worthington]

On Thu, 9 Jan 2020 23:35:04 +0100, you wrote:

>Hi everybody,
>
>I've just added a patch from Mark Spieth to mythtv-setup that enables
>getting the logical channel numbers from broadcasters such as Sky
>(US/IT/NZ/AU), Dishnet(US) and others that use OpenTV.
>Unfortunately I cannot receive an OpenTV channel but I am very
>interested in how it works so if anybody can try it and report back
>then yes please!
>
>I am also very interested in a full transport stream capture of these
>signals for analysis purposes. It is now relatively easy to capture
>the full stream, a.k.a. MPTS channel, with MythTV. One minute would be
>great!

I use MythTV to record from Sky New Zealand, and I get my OpenTV EPG
from the Optus D1 12519 transponder, which has full EPG for all the
Sky NZ channels on all transponders:

https://www.lyngsat.com/Optus-D1.html

I used dvbsnoop to capture 60 seconds from 12519 and I have put it on
my web server:

http://www.jsw.gen.nz/mythtv/SkyNZ_OpenTV_12519.ts
(233,252,565 bytes)

My web server runs on an ancient OS/2 setup, and only supports single
threaded downloads, without any ability to restart failed downloads.
And New Zealand is a long way from anywhere in terms of Internet ping
times.  So I recommend using wget from a Linux box for large downloads
from my server to get the best speed.

Let me know if you would like more (or different) data captured from
Sky NZ.  I am not certain that 60 seconds is enough to contain a full
cycle of the EPG data.

For my EPG grabbing, I am using a copy of tv_grab_dvb_plus that I have
heavily modified to work with the current Sky NZ OpenTV data.  It
works well enough to get the EPG for the channels I use on Sky NZ, but
it is far from perfect and does not get correct data for all the SkyNZ
channels.  It does see the LCNs (logical channel numbers), and I have
modified it to provide the LCNs as a "number=" field in comments in he
XML output.  Let me know if you would like a copy of the source.

The original tv_grab_db_plus is here:
https://sourceforge.net/projects/tvgrabeit/

If you have managed to find proper documentation on the OpenTV EPG
format, I would love to have a copy as that should allow me to make
tv_grab_dvb_plus fully compatible.  At the moment, there are a number
of descriptor types that it does not know how to decode.  I only have
the basic DVB documentation to work from, nothing that is OpenTV
specific.  The original authors of tv_grab_dvb_plus do seem to have
had more than that.