[mythtv-users] Synchronising frontends

[Russell Gower]

On 15 Nov 2010, at 11:26, Andre wrote:

> 
> On 15 Nov 2010, at 10:55, Russell Gower wrote:
> 
>> Hi,
>> I'm currently running a 0.23 system on Debian Lenny (will upgrade when 0.24 packages become available) using separate front and backend servers. My Frontend netboots from the backend with a NFS root filesystem and is connected via HDMI to my lcd TV in the lounge for video and a spdif cable to my amp for audio. 
>> 
>> I would like to add a slave system in the kitchen, so that we can watch TV whilst cooking etc, I'm currently investigating my options - The key requirement  is that playback should be synchronised with the existing front end!
> 
> The only way you will get synchronised audio is by feeding the same already decoded audio to both locations, e.g feed pcm stereo to both via spdif, ac3 passthough can be out of sync when using different decoders!
> 
> Alternatively most surround amps have an analog second zone output, this will be guaranteed to be in sync as it's coming from the same amp. I'm assuming the amp in the living room will be on otherwise who cares about sync.

Unfortunately my amp doesn't have a second zone although it does have a headphone socket so a hack may be possible, I could run a set of speakers in parallel to the lounge ones but I would loose independent volume control.

> 
> Of course it's highly likely that the LCD in the kitchen will have a different delay to the one in the living room even if fed from split HDMI, so video won't be in sync with audio! It's going to be one of those pick any two from three issues.
> 
> In my experience even slight audio differences are extremely noticeable and annoying, especially if they change over time which any streamed and almost all digital solutions will do. The ONLY guaranteed properly in sync solution will be completely analog, amp second zone, parallel speakers or similar.
> 
I should have mentioned I currently have a set of speakers in the kitchen connected the the line output on the TV, but these only work when watching TV outside of Myth - audio is ever so slightly out of sync but this is only noticeable from the corridor where you can here both sources, when in either room you can't notice it.

> Andre

Thanks
  Russell