----- Original Message -----
From: Roman Haefeli reduzent@gmail.com To: Jonathan Wilkes jancsika@yahoo.com Cc: tim vets timvets@gmail.com; Pierre Massat pimassat@gmail.com; James Dunn james@4thharmonic.com; pd-list pd-list@iem.at Sent: Tuesday, September 20, 2011 3:35 AM Subject: Re: [PD] stop sample playback when phasor~ reset?
On Mon, 2011-09-19 at 14:00 -0700, Jonathan Wilkes wrote:
From: tim vets timvets@gmail.com To: Pierre Massat pimassat@gmail.com; James Dunn
james@4thharmonic.com; pd-list pd-list@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.
That depends on how one uses [phasor~]. In the example above the initial ramp must start on a block boundary-- whatever is triggering [del <time>] must also send the relevent frequency to [phasor~] for playing the sound stored in the array. Those actions must happen with control objects, which means they will affect the signal objects at the beginning of the next block.
However, for the ramp at the end of playback [phasor~] as used above can produce a ramp that begins/ends in the middle of a block ( [vline~] too), whereas [line~] cannot. Of course I'm just talking about situations implied by the example above, where the user is just triggering events sporadically using control objects. Neither [line~] nor [vline~] will trigger a ramp in the middle of the current block, so if you're rule is "IF sample playback THEN [vline~] > [line~]" there are probably times you're wasting cpu.
The first paragraph of 3.audio.examples/C04.control.to.signal.pd spells it out pretty well.
-Jonathan
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