[mythtv-users] Can I play music on 2 frontend simultaneously?

Robert M. Riches Jr. rm.riches at jacob21819.net
Tue Feb 21 00:17:02 UTC 2012


> Date: Mon, 20 Feb 2012 21:41:13 +0100
> From: Thomas Carri? <thocar at free.fr>
> To: Discussion about mythtv <mythtv-users at mythtv.org>
>
> Hello,
>
> I am new to MythTV, my goal is to play music simultaneously on the Hi-Fi 
> Amplifier of the living room and the Amplifier of the bedroom.
>
> Basicly it is what http://www.apple.com/itunes/airplay/ can do wireless.
>
> In my case, I want to do it wired with opensource software, I have :
> - 2 eee pc connected to the amplifier with mini-jack to RCA cables
> - a wired network
> - a repository of ogg files.
>
> Do you know if and how I can achieve this with MythTV ?
>
> Thanks for your answers

You might look into running a single MythFrontend and using
NetJACK (Jack Audio Connection Kit) to send the audio from the
real frontend to the other unit.  NetJACK can be a bit of a
challenge to set up, but it seems to work pretty well.  When I
set it up for a zero/thin-client situation, I had to set up an
ALSA loopback soundcard on the server (JACK slave) side.

Whether you use NetJACK or two independent MythFrontends,
relative to another reply's statement about the required degree
of synchronization, I would think you could likely get by with
more than the couple of ms difference for roughly equal levels or
a couple dozen ms for differing levels.  Keep in mind that sound
in air travels about a foot per ms.

Here are a couple of hypothetical examples that may illustrate
real-life synchronization differences between speakers driven by
the same signal.  First, if you had two speakers about 10 feet
apart driven by the same signal, and listeners sitting on a long
couch about 10 feet away, moving between ends and center of the
couch would introduce differences of synchronization of >= 2ms.
Second, think of two speakers driven by the same signal about 100
feet apart outdoors.  A listener 45 feet from one and 55 feet
from from the other would hear a difference of 10ms.  A listener
at a 40-60 location would hear a difference of 20ms without much
difference in level.

Would those synchronization differences be a problem?  I wouldn't
think so, but YMMV.

HTH

Robert


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