[PD] stop sample playback when phasor~ reset?

[Roman Haefeli]

On Tue, 2011-09-20 at 09:43 +0200, Pierre Massat wrote:
> I m curious to know which object you would recommend instead of
> threshold~ (the delay way is obviously not feasible as soon as you
> need to change the speed of phasor~ during palyback).

Yeah, [threshold~] seems feasible, but this approach suffers from a few
issues. As I said before, the bang comes only on block boundaries and is
at least one block late, so it's not very precise. Also, a [phasor~]
probably never reaches exactly 1 (or 0) and it is less likely the higher
the frequency is. So you would need values like 0.001 or 0.999 for the
[threshold~] which again makes it a bit more imprecise. 

You can also use the [vline~] approach and change the speed in the
middle of the playback, though it needs a bit of patching to accomplish
that. You need a delay, that is triggered at the time of the speed
change. The delay value can be used to calculate the current position of
the play head. Then you can use that value as a start point for a new
message to [vline~]. 

Roman


> 2011/9/20 Roman Haefeli <reduzent at gmail.com>
>         On Mon, 2011-09-19 at 14:00 -0700, Jonathan Wilkes wrote:
>         >
>         >
>         >
>         >
>         > >________________________________
>         > >From: tim vets <timvets at gmail.com>
>         > >To: Pierre Massat <pimassat at gmail.com>; James Dunn
>         <james at 4thharmonic.com>; pd-list <pd-list at iem.at>
>         > >Sent: Monday, September 19, 2011 4:08 PM
>         > >Subject: Re: [PD] stop sample playback when phasor~ reset?
>         > >
>         > >
>         > >When you use phasor~, you normally already know how long it
>         will take for the sound to be finished playing (because you
>         set its frequency to play it back at the proper speed)
>         > >Store the information about the sound loaded (or recorded)
>         and use that to stop the playback after one play duration.
>         > >
>         > >
>         > >[del <time>]
>         > >|
>         > >[t  b  b]
>         > >|        |
>         > >[0(     [0(
>         > >[        |
>         > >[phasor]
>         >
>         > What's the benefit of this over a line~ based approach?
>         >
>         
>         [line~] is inferior to [phasor~] in that it only starts a ramp
>         on block
>         boundaries. Using [vline~] seems to me most flexible in terms
>         of sample
>         playback as it can start a ramp even in-between samples.
>         
>         Using [threshold~] or any other method to detect the reset of
>         [phasor~]
>         is not feasible, because of two reasons:
>          * [threshold] (but also [snapshot~]) output the bang only at
>         block
>         bounaries, so the detection is not very precise
>          * Whenever the the audio domain (a signal) causes an event in
>         the
>         message domain (that's what [threshold~] and [snapshot~] are
>         for), the
>         event is at least one block late.
>         
>         There is still one advantage of [phasor~] over [vline~]: The
>         speed of
>         the [phasor~] can be changed at signal rate, so one can create
>         continuous pitch changes when playing the sample. That's not
>         possible
>         with [vline~].
>         
>         Roman
>         
>         
>