In Pd of course, anyone?

looking for velvet noise generator

I gave it a shot using zexy relationals, might be more efficient using other externals (hence "pure")
edit: realized I didn't need one of the[samphold~]
s
edit2: now I realize there is also the possibility of missed periods in the case that the[phasor~]
wraps around to a value higher than the[samphold~]
ed[noise~]
.. hmm..
edit3: 3rd time's the charm? used another[rzero~]
to put a 1 in there when the[phasor~]
wraps
purevelvet.zip 
why do you have a reset phase input for phasor~?
what do you mean by "make sure there is at least 1 1 on wraparound"?
this can be easily made 100% vanilla with expr~
although I see the implementation, I still don't really know how a velvet noise generator is defined so I can check this patch's implementation and maybe think of alternatives, can you help?
thanks

@porres oh yeah I always forget about
[expr~]
for some reason.. maybe bc of the license it used to have.There's no real reason to have the phase reset inlet, just more control.
From what I can tell, velvet noise is outputting a 1sample impulse of value that's either 1 or 1, chosen randomly, at a random point in a regular period.
So I have a[phasor~]
to keep track of the period, and the[samphold~]
samples a random value from 01 when the[phasor~]
resets. This will be the point in the phase of that period that the impulse will occur. When the[phasor~]
gets to above or equal to this value, the[<~ ]
will go from 1 to 0. That goes into[rzero~ 1]
, which will put out a 1 on the sample that occurs. That goes into the[==~ 1]
, which acts (together with[*~ ]
) as a gate for the noise value that has been manipulated to either be 1 or 1, depending on if the output of[noise~]
is positive or not.The issue with this original implementation was that when the
[phasor~]
wraps around to start a new phase, it can wrap to a value greater than the new[samphold~]
value from the noise. That means that if the noise value is very small, there will be no impulse for that period since the[phasor~]
value will never be less than the sampled noise value for that period (and therefore the[<~ ]
won't go from 1 to 0, which means the[rzero~ 1]
below it won't output a 1, and so on). So, the[rzero~]
and[<~ 0]
put out a 1sample value of 1 when the[phasor~]
wraps around, which is combined with the other signal in[min~ 1]
to take care of this. That way the[rzero~ 1]
below the[min~ 1]
will get a 1 even if the wrappedaround[phasor~]
value is less than the new sampled noise value, and there will be an impulse for that period.
(that is what "make sure there is at least 1 1 on wraparound" means)edit: after writing all of this it occurred to me that the sampled noise value could also be greater than the value that the
[phasor~]
will get to before it wraps around.. perhaps the solution is to constrain the sampled noise value depending on the frequency and phase of the[phasor~]
... 
here's a max patch, what do you think?
easy to do with cyclone
reference
https://llllllll.co/t/techniquesforgeneratingclickspopshissandnoise/31314/45 
@porres the user's explanation for the basis of that patch doesn't seem to fit what is described in this paper: https://www.researchgate.net/publication/260701331_A_Perceptual_Study_on_Velvet_Noise_and_Its_Variants_at_Different_Pulse_Densities
but it seems like there are a few different types of velvet noise. The original seems to be 1 impulse (chosen to be randomly either 1 or 1) randomly placed in time within a regular period. (which is not what the above patch does)
that's not to say it might not be a different type though, I only looked at the original 
@porres here's another simplertoimplement type described in the paper  "totally random noise"
totalvelvet.zip 
there is a good description here: https://acris.aalto.fi/ws/portalfiles/portal/13412521/applsci_07_00483_v2.pdf
it seems similar to dust2 in supercllider (and I ported that to ELSE already)

@porres the first version I posted is what is described in that paper. If you look at figure 1a you can see that there is 1 impulse randomly placed within a regular interval (which is shown by the red dashed lines in the figure).