Advice on setup please

[smurfyou]

AFAIK there is still no way to fully genlock while going through the Renderer. Which is why Aux I/O is the lesser choice since it's not consistent.

[Greg Malcangi]

Originally Posted by its2loud

The Pro Tools Audio Bridge virtual devices which come preinstalled have a built in clocking mechanism which custom virtual devices don’t have so these should be used where possible.

Thanks for the info but this is where I find it a bit confusing, as Avid also states in regard to using Aux I/O: “The Dolby Atmos® Production Suite includes the Dolby Audio Bridge, which also can leverage the Pro Tools syncing mechanism …”.

So as I understand it: Output from PT to the DAB through Aux I/O (when using HDX/Hybrid Engine) should provide delay compensated, sync’ed input into the Renderer. I presume the output from the Renderer can be set to HDX/Digilink? If so, the HDX input latency would also be delay compensated but delay compensation obviously cannot account for the latency of the Renderer itself (the processing time required by the Renderer). So therefore the question becomes:

Originally Posted by smurfyou

AFAIK there is still no way to fully genlock while going through the Renderer. Which is why Aux I/O is the lesser choice since it's not consistent.

Thanks smurfyou but what exactly does “not fully genlocked” and “not consistent” mean? In other words (and continuing from my previous paragraph): The input to the Renderer is effectively genlocked and the output from the Renderer (set to HDX) is also genlocked/delay compensated but where we loose genlock/sync is the delay incurred by the Renderer’s latency/processing time, which we cannot accurately compensate for (using say a manual Hardware Insert Delay) because it’s not consistent.

So my question is: What amount of inconsistency/variable latency are we talking about? If it’s say 1ms - 5ms that wouldn’t be a problem for me but if it’s say 1ms - 40ms, that’s a whole frame and completely negates any benefit of having frame edge sync in the first place. Even if the latency varies between say 10ms - 25ms, then a Hardware Insert Delay (assuming that’s possible) of 10ms would result in a max error of 15ms (about 1.5 quarter frames), which is not “fully genlocked” but would still be just about OK for me.

I’m guessing there’s probably no way to know what amount of variability/inconsistency there’s likely to be, that it’s dependent on available processing power and session size? So unless someone has actually tried this setup with a Mac Studio Ultra I’m not going to get any accurate answers, although even a rough figure with a different Mac would give me a ball park idea of what amount of inconsistency we’re talking about.

Thanks again for your responses, G

[smurfyou]

Originally Posted by Greg Malcangi

Thanks for the info but this is where I find it a bit confusing, as Avid also states in regard to using Aux I/O: “The Dolby Atmos® Production Suite includes the Dolby Audio Bridge, which also can leverage the Pro Tools syncing mechanism …”.

So as I understand it: Output from PT to the DAB through Aux I/O (when using HDX/Hybrid Engine) should provide delay compensated, sync’ed input into the Renderer. I presume the output from the Renderer can be set to HDX/Digilink? If so, the HDX input latency would also be delay compensated but delay compensation obviously cannot account for the latency of the Renderer itself (the processing time required by the Renderer). So therefore the question becomes:

Don't confuse the two though. You'd use DAB as the playback engine, not through Aux I/O. Then HDX (or MTRX Studio Thunderbolt) as the Renderer output.

But when you select DAB you lose the Sync HD / SyncX connection.

[Greg Malcangi]

Originally Posted by smurfyou

Don't confuse the two though. You'd use DAB as the playback engine, not through Aux I/O. Then HDX (or MTRX Studio Thunderbolt) as the Renderer output.

But when you select DAB you lose the Sync HD / SyncX connection.

Ah, but now I am confused :)

Can’t you run PT with the playback engine set as HDX/Hybrid Engine and then choose the DAB as an Aux I/O for output, rather than the other way around? That way you would still have the Sync HD connection with frame edge sync and the DAB will still “leverage the Pro Tools [Aux I/O] syncing mechanism”. With the Renderer’s output set to HDX, the only issue should be the variable latency/processing time of the Renderer. Am I misunderstanding something?

G

[smurfyou]

Originally Posted by Greg Malcangi

Ah, but now I am confused :)

Can’t you run PT with the playback engine set as HDX/Hybrid Engine and then choose the DAB as an Aux I/O for output, rather than the other way around? That way you would still have the Sync HD connection with frame edge sync and the DAB will still “leverage the Pro Tools [Aux I/O] syncing mechanism”. With the Renderer’s output set to HDX, the only issue should be the variable latency/processing time of the Renderer. Am I misunderstanding something?

G

The DAB "leverages the Pro Tools syncing mechanism" whatever they mean by that. I don't believe Aux I/O does.

But Paolo M said he's worked with the setup you describe and it's fine. I haven't personally tried it. Just trying to point out the difference between DAB as the Playback Engine and DAB through Aux I/O.

I don't like Aux I/O for anything critical but I'm also not running 2023.3 so I'm not the best judge here . Perhaps its improved.

[Greg Malcangi]

Originally Posted by smurfyou

[1] The DAB "leverages the Pro Tools syncing mechanism" whatever they mean by that.

[2] But Paolo M said he's worked with the setup you describe and it's fine. I haven't personally tried it. Just trying to point out the difference between DAB as the Playback Engine and DAB through Aux I/O.

1. I don’t know exactly what they mean by that either. Best I can gather is that it’s effectively genlocked at the output from PT but what happens at the input of the Renderer PT doesn’t know about and can’t do anything to compensate for.

2. That’s certainly encouraging, it indicates that the DAB through the Aux I/O doesn’t make the sync so bad it’s unusable and my option #1 should in theory have somewhat tighter sync overall because it includes a Sync peripheral while the system he uses doesn’t. On the other hand, being “pretty happy with it” is rather vague and might not be good enough for the sort of post work I do. It would be great to get a rough idea in milliseconds the sort of latency variations the DAB fed through the Aux I/O incurs. Maybe someone will stumble across this thread in the next few days who’s tested it?

G