[PD] Question on [signmund~] tracks with 0 amplitude

João Pais jmmmpais at gmail.com
Fri Apr 17 22:12:41 CEST 2020


ok, that makes sense. I did already create something using delete, as 
I'm applying a dynamic color to the arrays after they've been created. 
But having a look at the the partial-trace makes more sense.

Best,

Joao


> I think I see what happened - the recorded trace reports 0 dB but this is
> the output of a 'rmstodb' conversion in the patch - I presume sigmund~
> is finding a peak at amplitude less than 1/10000 which then gets converted
> to zero.
>
> Something similar was happening with your earlier test runnign phasor~ into
> sigmund~ - there are very quite peaks in phasor~ output because of foldover,
> and sometimes sigmund~ picks them up, sometimes not.
>
> If you want to suppress very quite traces from the partialtracer patch, you
> can alter the add-trace abstraction to consider a trace empty if it's below
> an amplitude threshold and then to start a new trace if a trace then goes
> from below threshold to above threshold.  Alternatively, now that it's possible
> to delete scalars using th pointer object, you can make something that culls
> very quiet traces after the fact.
>
> cheers
> Miller
>
> On Sun, Apr 12, 2020 at 11:56:38AM +0200, Jo??o Pais wrote:
>> Here is a txt with the tracing I did using the doc patch - a contrabass
>> tone.
>> The 0-amplitude tracks appear when there is more silence, in this case
>> after the 2nd half of the sample.
>> I produced this file by sending a "write" to pd-trace-list, with load you
>> can load it into the same patch.
>>
>> Best,
>> Joao
>>
>> Am So., 12. Apr. 2020 um 04:07 Uhr schrieb Miller Puckette <msp at ucsd.edu>:
>>
>>> It's possible to have nothing in a track - in that case, the flag (the 4th
>>> item in the list sigmund~ outputs) should be -1.
>>>
>>> If that flag is saying there's a sinusoid of amplitude zero, something's
>>> wrong with sigmund~.
>>>
>>> cheers
>>> Miller
>>>
>>> On Fri, Apr 10, 2020 at 11:29:35PM +0200, Jo??o Pais wrote:
>>>> Hello list,
>>>>
>>>> I'm trying out [sigmund~], and wanted to confirm something related to
>>>> results I'm getting. When using the patch
>>>> doc/4.data.structures/14.partialtracer (and also a derivate patch of
>>> mine),
>>>> I get lots of tracks with 0 amplitude as result of the analysis.
>>>> The settings are [sigmund~ -t -npts 1024 -npeak 40 -maxfreq 8000 peaks
>>>> tracks] in the help file, and [sigmund~ -t -npts 2048 -npeak 200 tracks]
>>> in
>>>> my patch.
>>>>
>>>> When comparing the result of the analysis with a spectrogram of the
>>> sample,
>>>> the frequency content does match - the tracks with 0 amplitude don't
>>> exist
>>>> in the sample, i.e. they're silence.
>>>>
>>>> My doubt is, is it normal to have tracks with 0 amplitude? Or is there
>>>> something wrong with the analysis settings?
>>>> (if these tracks are a derivative of [sigmund~], that's fine, I can
>>> filter
>>>> and delete them afterwards)
>>>>
>>>> Best,
>>>>
>>>> jmmmp
>>>






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