Phantoms and home cinema

[fgueho]

But you have two phantoms, right?
So even if it's plugged in one of the phantoms, it still passes through the dialog, right?
So what's the difference?
And what is the interest to plug in the dialog if it doesn't work properly, right now?

[JohnnySix]

I think there's misunderstanding here between what we actually have and what I wish we had. I'd like a Johnnysix Realtime Stereo Mode, where the same optical signal can be divided at source with an optical splitter, and passed into both Phantoms simultaneously, with two optical cables. This speed-of-light signal would be naturally synchronised without the Dialog, and each Phantom would extract left or right channel accordingly.  

Yes, it is true that this is NOT possible right now, and playing back stereo can presently only be done using a Dialog to collect & re-distribute the signal, introducing latency. 

[fgueho]

Okay, but I'm surprised. I have read that you can have stereo by pluging in one of the two phantoms.
And that's what Devialet support told me too, when the dialog optical plug was not yet activated.
They said that I needed a dialog (for stereo purpose), but that I could use a phantom optical plug.

[cpa199]

Okay, but I'm surprised. I have read that you can have stereo by pluging in one of the two phantoms.
And that's what Devialet support told me too, when the dialog optical plug was not yet activated.
They said that I needed a dialog (for stereo purpose), but that I could use a phantom optical plug.

Can confirm stereo works with connection into phantom not dialog, just tested it as that's how mine are connected to minimise lag.

[JohnnySix]

To clarify, yes, I should have mentioned you can use optical into Dialog OR into one Phantom. Either way, the signal gets passed back and forth instead of simply coming straight out of the connected Phantom.

[Phs]

I did a quick measurement of audio delay on Phantom using ethernet cable between Dialog and Phantom both running 1.1.2.0
Phantom alone (without Dialog), fed on optical input gives 222 ms delay
Phantom + Dialog fed on Phantom's optical input gives 222 ms delay
Phantom + Dialog fed on Dialog's optical input gives 235 ms delay

This means roughly 5.5 video frames delay. This is way too much to achieve acceptable audio/video sync. The sync problem is obvious and annoying both on dialog lipsync in movies and live music performances.
In pro applications we consider 1 frame delay to be an acceptable maximum since most people can already see a 2 frames sync issues.

I wonder if Devialet can really reduce the current delay to an acceptable value ...

PH

[fgueho]

So no real differences with or without Dialog.
The problem is with the phantoms...
Thanks for your measurements.
Let's hope Devialet can do something about it. Or I won't buy them...

I am really disappointed.

[JohnnySix]

I second the gratitude for your measurements. It backs up my own 220ms initial estimation elsewhere on this Forum (done with ear & eye!). Oddly though, I now find I only need 100ms sync adjustment on my Media PC following the 1.1.2 update.

[Phs]

I believe that the difference between the value I measured and what you have to input as a delay in your media PC is due to the fact that both are measuring different things
What I measured was a purely audio transport duration. Meaning the time it takes for Phantom to play a bip presented on it's optical input.
What you input as a delay in your media PC is the difference between the audio and video transport durations. Video processing inside a TV or beamer takes a bit of time for sure. That explain the different value IMO
PH

[fgueho]

@Johnny : with your 100ms adjustement in your media pc, you don't have any sync problem between audio and video?
So your only problem is with TV?