[gmpi] Re: lost-n-found #2 latency

On Thu, Oct 14, 2004 at 03:26:27PM -0600, Mike Berry wrote:
>       I happen to think that this is one place where VST works pretty 
>       well, finding a fair balance between plugin flexibility and host 
> complexity. Following VST would mean:
> 
> 1.) Plugins must report their latency when the graph is started.
> 2.) Plugins can change the latency they report any time they are asked. 
> However, hosts will only ask at times that are convenient. This means 
> that for most hosts, dynamic latency correction while the graph is 
> running will not happen, but it would be possible to write a host which 
> did compensate dynamically.

That sounds fair to me.  anyone else have thoughts?  I'll add a Latency
section to the reqs stating the above...

>       As for the other questions, I think that plugins should always 
> assume that events received correspond to the time of the input data, not 
> the output. So a parameter change will be heard by the user after the 
> latency has passed. I know that you could have some parameters which 
> could be applied without latency, such as the output volume of a 
> transform-based filter, but this would lead to a perplexed user, and I 
> don't want every parameter to have its own latency value.
>       This would also cover the DSP card case. If they have audio but not 
> control latency, then it is the plugins responsibility to buffer the 
> events as necessary.

I agree completely.  I think anything but a consistent approach is
problematic, probably.  I just want to make sure that the folks who want
to do weird things have a chance to have their say.  Last chance on this
one...
Going...
going...

> Mike
> 
> Tim Hockin wrote:
> >A few latency related items. 
> >
> >Do plugins need to report their latency?  Does it need to be dynamic? Can
> >a plugin change it's latency based on some parameter?
> >
> >There was an email discussion on latent plugins hinting that they should
> >receive their events early.  Do we want to deal with this?
> >
> >There was a discussion about DSP cards with audio latency, but no
> >control latency.  Do we want to deal with this?
> >
> >
> >
> >
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> >
> 
> -- 
> Mike Berry
> Adobe Systems
> 
> 
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-- 
Tim Hockin
thockin@xxxxxxxxxx
Soon anyone who's not on the World Wide Web will qualify for a government 
subsidy for the home-pageless.

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