In Pd of course, anyone?

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
pure-velvet.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 1-sample 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 0-1 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 1-sample 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 wrapped-around [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/techniques-for-generating-clicks-pops-hiss-and-noise/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 simpler-to-implement type described in the paper - "totally random noise"
total-velvet.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).