[mythtvnz] DVB multicasting

[tortise at paradise.net.nz]

----- Original Message ----- 
From: "Ross and Jemima Knudsen" <ross.jemima at gmail.com>
To: "MythTV in NZ" <mythtvnz at lists.linuxnut.co.nz>
Sent: Tuesday, October 27, 2009 10:46 AM
Subject: [mythtvnz] DVB multicasting


Hi all,

I've been working on multicasting my FreeviewHD content on my LAN.  I've
been using mumudvb which I've got up and running (last night).  It can
multicast an entire transponder on the network for each card you have.
I have two tuners so I managed to multicast the TVNZ and Canwest
transponders together.  I was able to view all these channels using VLC
on an Ubuntu and Windows 7 box over ethernet.  The wireless wasn't able
to handle it (not sure why maybe the WPA overhead is too much).  Problem
is now I want to get my mythbackend to 'tune' these channels.  I
semi-followed JYAs howto here:

http://avenard.com/iptv/Setup.html

Using network recorder as the tuner card and using a m3u playlist to
load the channels.  The whole backend setup seems to work without a
hitch but when you try to watch live TV on the frontend it times out
saying that I should have received a lock by now.  I'm not sure whether
the problem is a OS configuration problem, a Myth problem or some other
problem as the same m3u playlist file works with VLC on the same
machine.  I wonder if it has something to do with subscribing to the
multicast group.  This is my m3u file (the IP addresses are the default
ones used by mumudvb):

#EXTM3U
#EXTINF:-1,TV ONE
udp://@239.100.0.0:1234
#EXTINF:-1,TV2
udp://@239.100.0.1:1234
#EXTINF:-1,TVNZ 6
udp://@239.100.0.2:1234
#EXTINF:-1,TVNZ 7
udp://@239.100.0.3:1234
#EXTINF:-1,TV3 PLUS 1
udp://@239.100.1.0:1234
#EXTINF:-1,TV3
udp://@239.100.1.1:1234
#EXTINF:-1,C4
udp://@239.100.1.2:1234

If I can get this to work then it means I can share my tuner hardware
with the entire network.  It also means you could (if you wanted to) run
mythbackend in a VM which would enable you to play around with various
configurations...

_______________________________________________

Be nice if VLC had vdpau function to allow it to run on lower spec CPU's, I wait....however mplayer (and maybe myth?) also can 
display direct LAN streams.

Hdhomeruns to some extent do what you may be seeking, all be it as a single networked device. There is also a TECH version which is 
specifically designed to multicast and a DVB-T one is I understand not far away....

Makes me wonder what is the lowset spec CPU requirement for a DVB-T tuner(s) to exist solely for a network tuner device that mimics 
the Hdhomerun?

It seems you are considering blasting the LAN with all channels, much like RF also works, however I am not sure the LAN has the 
capacity to cope with all that traffic, certainly ordinary wireless LAN is well understood to not cope at all well with multicast 
traffic.  When a (?optical) LAN can cope with all the traffic the need to control a tuner may diminish, however that seems to be the 
current design model.  Also with our 3 multi channels one could have 3 tuners, not so sure how it would work in the US with X 
channels?!

Not sure what your goals are here, can you clarify the end goals?   What sort of config options did you want to play around with?

I'd like to have a myth backend multicast its stream to frontends, so that other frontends could hop on to simultaneously play the 
same stream.... Control issues are likely to arise.   Perhaps it is a simple as using a multicast IP for the backend IP, I have yet 
to try that.