Re: [linux-audio-dev] XAP: a polemic

<My views> Tempo remains in effect. Transport time is only meaningful to the sequencer. Why should a plugin care what point in the song you are at? Why should a plugin care if the play-pointer moves? Audio time (sample-count) runs endlessly (host can actually stop it if it can know there is nothing going on at all, perhaps - blocked on user/MIDI - maybe). Because the sample-counter is tied to the tick counter directly via tempo, rate, meter, and ppqn (modulo tempo changes, which can come as events or whatnot) plugins don't need to actually track what tick number they are on, just the passing of ticks. Edge-dependent plugins, if there is such a thing, can see when (samples_per_tick*ppq) samples has elapsed and know a beat has happened. Absolutely essential, IMHO. Now, I've become very confused. What is it that we are arguing about? We seem to all be talking in circles, so I'm going to describe what I understand and I want to steer the discussion towards a solution :) * Host sends buffers of N samples to plugins, with a starting timestamp * Things send timestamped events to plugins * Timestamps are measured in whole audio samples * Host/timeline must export/deliver: - SAMPLE RATE (samples/sec - passed at instantiation) - TEMPO (sec/tick - event?) - PPQN (ticks/qn - host-global? event? fixed?) - METER (units? - event?) * Plugins can track ticks by adding 1/(rate*tempo) to a counter and observing an integral boundary crossing. So the questions that remain: * what am I missing? * how do external clocks tie in? (I know _nothing_ about them!) * units for meter (I don't know enough music theory to answer properly) * can we take any of this tracking work away from the plugins? This argument is getting tired - lets resolve it.. Tim