[PD] pix_motion_sector

[William Brent]

I see - [pix dump] will give you a list you can search to accumulate
the number of pixels associated with movement.  I was hoping for an
object that would return that value, but maybe accumulating in Pd is
no slower in this case.  To me it's just a preference...I'd rather
have an extern than an abstraction for some things.  But that's the
beautiful thing about Pd - you can make what you want however you
like. :)


2010/5/14 Jack <jack at rybn.org>:
> Le vendredi 14 mai 2010 à 06:49 -0700, William Brent a écrit :
>> I implemented Miller's phase vocoder from the documentation in C and
>> was amazed to see that the CPU load was exactly the same.  So much for
>> improving efficiency...  But I have seen a big difference for
>> traversing tables and lists.  The process of summing the elements in a
>> large table is much faster in an extern than with an [until] loop.
>>
>> In the case of [pix_motion_sector], what's the easiest way to
>> duplicate the functionality of reporting % of pixels changed in the
>> region?  Is there an obvious way to count up the number of pixels that
>> crossed [pix_movement]'s threshold in the cropped region?
> [pix_dump] ? Maybe a faster method ?
> ++
>
> Jack
>
>
>>
>>
>>
>> 2010/5/14 IOhannes m zmölnig <zmoelnig at iem.at>:
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>> > Jaime Oliver wrote:
>> >> On Thu, May 13, 2010 at 7:40 PM, Mathieu Bouchard <matju at artengine.ca>wrote:
>> >>
>> >>> On Thu, 13 May 2010, William Brent wrote:
>> >>>
>> >>>  Yes - it's exactly that: an adaptation of pix_movement that lets you
>> >>>> specify an area to analyze.  That way you can use several instances to
>> >>>> create multiple regions for triggering different events.  I haven't looked
>> >>>> at this in two years!  I'll take a look at the helpfile and see what's
>> >>>> missing/unclear.
>> >>>>
>> >>> what's the difference between that, and using [pix_crop] and [pix_movement]
>> >>> with [pix_separator] ?
>> >>>
>> >>
>> >> Please correct me if I'm wrong,
>> >> Doesn't having these as externals instead of abstractions, make it
>> >> significantly faster/efficient?
>> >> particularly if you have many of them?
>> >>
>> >
>> > no not necessarily.
>> > the overhead for message communication between objects is usually quite
>> > small, compared to the pixel operations.
>> >
>> > you would only need [pix_crop]->[pix_movement] without the
>> > [pix_separator] (since the crop will have to allocate a new image
>> > anyhow), thus no need for the extra copying of data.
>> >
>> > the only speedup you could expect from pix_motion_sector (i haven't
>> > looked at the code), is that you wouldn't have to copy the data for
>> > cropping at all, but only use the pixels in the ROI.
>> >
>> >
>> > as for williams argument, that you need less objects, i would suggest
>> > looking into abstractions :-) it's definitely less lines of code (at a
>> > minimum 10 lines of Pd code) and still only a single object...
>> >
>> > mfgasdr
>> > IOhannes
>> >
>> >
>> >
>> >> best,
>> >>
>> >> J
>> >>
>> >>>  _ _ __ ___ _____ ________ _____________ _____________________ ...
>> >>> | Mathieu Bouchard, Montréal, Québec. téléphone: +1.514.383.3801
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>> >>
>> >>
>> >>
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-- 
William Brent
www.williambrent.com

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