[nama] Re: Latency compensation

On Wed, May 02, 2012 at 05:51:26PM -1000, Joel Roth wrote:
> Hi,
> 
> I've finished a rough cut of coding for 
> latency *measurement*.
> 
> I need to go over it again, because there
> is a problem with units: LADSPA plugins
> return latency in milliseconds; JACK
> clients report latency in frames,
> where one frame is 1/sample rate.
> 
> We'll need some work and creativity
> to test all this work, but for now
> if anyone has time to look over the code,
> I'm sure it will help.
It's fairly straightforward code: the only bit I couldn't wrap my
(admittedly small) mind around is this cascading assignment:
          $setup->{sibling_latency}->{$_->wet_name}
        = $setup->{sibling_latency}->{$_->dry_name}
        = $setup->{track_latency}->{$_->wet_name}
        = track_ops_latency($::tn{$_->wet_name})
                + $additional_latency

The code indeed needs to be fixed for mismatched units, as you say. Note
that frame/srate will give you a value in microseconds, not miliseconds,
so the code in loop_device_latency needs to be modified. Perhaps it
would make more sense to tally latency in samples separately and convert
it to miliseconds just once?

Cheers,
S.M.

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