+trigger, Re: [linux-audio-dev] ladspa.h.diff

Steve Harris S.W.Harris at ecs.soton.ac.uk
Fri Mar 5 20:16:58 UTC 2004


On Fri, Mar 05, 2004 at 07:14:41 +0100, Tom Szilagyi wrote:
> I like this new LADSPA spec. very much, thanks to Tim Goetze for working
> it out! However, i have one bit of concern:
> 
>   /* This member indicates the delay, in 1 / (sample rate) time units,
>      the plugin imposes upon processed signals. */
>   const LADSPA_Data Latency;
> 
> Wouldn't this break the possibility of adequate operation of plugins that
> have a latency value dependent on user settings (ie. not constant)?

The problem with non-constant latency is that it requires the host to set
the parameters and call run() once before it will know the value.

Also the semantics of variable latency are very confused - as the value
can vary at any point furing the run() steps the host cant know how to
correctly interpolte between adjcent values. Its just much to hard to do
anythign useful with.

I also /really/ dont think it belongs in the struct - its not an essential
feature and few hosts will support it.

Either design your plugins to do internal lantecy correction and report
the total or live with uncorrected latency :)

- Steve 



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