[mythtvnz] DVB multicasting

[Nick Rout]

On Tue, Oct 27, 2009 at 2:57 PM, Tortise <tortise at paradise.net.nz> wrote:

>
> OK there might be times when people want to watch the same thing at
> the same time at different TV sets, but Myth doesn't stop you doing
> that.
> ==========================
> There is no myth provision for synchronised control / viewing on multiple frontends that I am aware of.  LIRC might be our friend
> here.

There is no provision for synchronised viewing. However if we all want
to watch top gear live then you set it to record on the backend. Any
numbber of frontends can watch that recording, live or within a few
seconds of live. (Why you would want to, and have to sit thru the ads
is another point)

>
>
> Two (or more) frontends can watch the same recording at once.
> They won't be synched, but they won't be under multicast either
> (becasue different systems will have different inherent delays).
>
> ============================
> "Inherent delays" and "won't be synched" wrt multicast???  we'd be talking millisecond delays here, I'd not see that as a concern.
> How would that be a concern?
>

I send a signal out multicast. To all intents and purposes each system
on my lan gets it simultaneously. However each machine has different
hardware. There could easily be a delay that is annoying, in that
there will be an "echo" in the sound. A few milliseconds can be
enough.


>
> Synchronising even music within a LAN is hard enough, let alone video
> as well.
> =============================
> Nick I understand mutlicast to be closely aligned to broadcast in this context, what is the synchronisation issue?  (e.g. vis-a-vis
> other broadcast media - what sync problems are there generally?)  Frontends are simply tuning into the same (UDP) stream, what is
> there to synchronise?  (Other than control)
>

see above. But maybe I exaggerate the problem. You can try it now with
the OP's setup suggestion. Let us know the result (I have no desire
for live TV and no desire for synchronisation)

> So you're not going to achive synchronisation too easily,
> ============================
> I am yet to be convinced.
>
> why not let them watch independently, and let each room do its own comfort breaks.
> =========================
> They can now, however as some of us see an advantage in synchronisation I hope you'll consider what it may have to offer and support
> us in that.
>