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?
2010/5/14 IOhannes m zmölnig zmoelnig@iem.at:
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Jaime Oliver wrote:
On Thu, May 13, 2010 at 7:40 PM, Mathieu Bouchard matju@artengine.cawrote:
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
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