[LAU] ArdourVST - Latency Management

[Fons Adriaensen]

On Thu, Jan 10, 2008 at 04:37:50PM +0100, Sebastian wrote:

> Okay. I tried it on my music machine but found another totally different 
> result. The latency of VST plugins gets compensated on tracks, but not 
> on busses.

I suspect Ardour is performing latency compensation 'the lazy
way', by just adding an offset to the sample indices used to
read a track that has processing latency, and make the transport
compensate for this, rather than by inserting _real_ delays in all
other processing paths.

This works, IFF the following assumptions are valid:

- all signals sources are tracks being played back,
- the signal from a track will not follow parallel paths,
- or if it does, all of them will have the same latency. 

It's simple and will work in many, but not all cases.

The more general solution, considering what can happen if you
have parallel processing paths (pre and post fader sends, 'real'
groups, tracks split off to a separate strip for some reason,
etc.) can be very complex - maybe too complex to allow for a
reliable  automatic compensation. 

In that case I'd prefer _no_ compensation at all to a partial
or wrong one - it makes a finding manual solution easier.

-- 
FA

Laboratorio di Acustica ed Elettroacustica
Parma, Italia

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