[linux-audio-dev] +momentary, consolidated (ladspa.h.diff)

[Steve Harris]

On Mon, Mar 08, 2004 at 03:22:57 +0100, Tom Szilagyi wrote:
> Fixed latency is not a big issue because a plugin can report the maximum 
> latency it could ever reach, and if the actual latency is lower it can 
> artificially delay its output internally. But i think this is ugly, 
> particularly because of the fact that we already have a working setup 
> with the "latency" control output which allows for changing latency as 
> well -- and this does make sense, since latency may depend on sampling 
> rate in a large number of cases, and since sample rate may vary almost 
> an order of magnitude, i think it would be suboptimal to impose a 
> needless delay on the whole processing line.

The problem is that if your plugin does have variable lantecy then the
host cant really support it anyway - it cant tell what the latency is at
any particular instant in time and it cant change the latency compensation
without introducing distortion into the output signal.

I have tried to write a host that did dynamic latency compensation without
distortion and gave up and implemented a version of the plugin with fixed
latency :) Its probably possible if your willing to let a bit of zipper
noise pass, but for JAMin that wasn't acceptable.

I'm not against variable latency per se (its what I support now), I'm just
not sure that its worth it.

Your point about sample rate or system dependency is well made. I'm not
sure how comman that is, but that could be an issue.

- Steve