[mythtv-users] Way out idea on watching same thing in multiple rooms

[Nick Rout]

On Mon, Jan 4, 2010 at 5:04 PM, Christopher X. Candreva
<chris at westnet.com> wrote:
> On Mon, 4 Jan 2010, tortise at paradise.net.nz wrote:
>
>> this might work.  I think the elegant and proper answer lies in multicast
>> streams, either from the FE or perhaps preferably the BE.  Using multicast
>> quite simply avoids any sync issues. Nick Rout made a suggestion that
>
> I don't think so. Think of two playback units with different sized buffers.
> Without sync data they can be at different points in the multicast stream.
> The stream starts comming in at the same time, but a system waiting for a
> (say) 20 meg buffer to fill will start after one waiting for a 10meg buffer
> to fill. Then when the master pauses, will simple tell the others
> to pause too ? If the master decides to rewind to hear the last line again,
> will the other follow ?
>
> Multicast solves a different problem, not sending the same data over the
> network two or three times. Perhaps for a situation where you had 20 or more
> screens to sync (like a mall I was in recently with monitors showing the
> same cartoons everywhere) that might be usefull. I don't think the average
> 100mbit home network is going to be overloaded by 2 or 3 machines watching
> at once.
>
> Again thinking broadly, and I know I'm going to mix metaphores here, what
> I'm suggesting should be possible by piping something like the regular
> standard out text stream of mplayer into the telnet interface of a myth
> frontend. All it has to say is play this, and this is where in the media you
> want to be.
>
> How to access it  -- NFS, SMB, multicast stream, or even a copy of the same
> file on a local disk -- is a separate problem.

I entirely agree with you, my contribution to tortise's other thread
was to point out how multicast might be achieved, I never claimed it
would produce in sync video in every room. Such is hard to achieve.
There are two open source projects that I know of that have achieved
it:

1. squeezebox will synchronise audio to many endpoints. I know this
works, although how much of it is in the hardware and how much is down
to the OS software I do not know. I have seen comments that it does
not work so well with the software clients as it does with the
hardware clients. And its only audio. Although the audio element is
more important - its more likely you will notice a difference in audio
between frontends in two different rooms than in the video  - you can
watch only one screen at a time but you could hear both audio streams
when transitioning around the house. Any slight 'echo' would be
annoying as hell.

2.  linuxmce claims to do it with video, although I have never seen it
as I have never installed it. For those who don't know, linuxmce was a
project/product that did a whole home linux based home entertainment
syatem. It had home automation as well as DVR functionality. The DVR
functionality is effectively a fork of a (now fairly old version of)
mythtv.

The code base of these two projects may provide good clues on how to
get what you desire. After all the GPL allows this!