Forums > Jitter

### jit.slide?

Apr 22 2006 | 12:25 pm

hi,
I’m using Jitter for the first time in an upcoming project. I was wondering whether anyone could provide me with an explanation of what jit.slide actually does?

Apr 22 2006 | 12:36 pm

Apart from the reference manual page?

Apr 22 2006 | 1:35 pm

Yes, "always consult the manual page" ( the hit single from the new CD by my
band, Grazing Zebra).

I struggled with this too until a light finally went on. It is related to
the question, "How far is it to Chicago in miles per hour?" Here is my
(more-or-less) plain language description.

When a jitter matrix passes through jit.slide, it "slides" from the previous
frame by an interpolation method that you see in the equation on the help
page. The time it takes to slide is determined by the slide up/down values.
These values are not in fact time but rate. The further the distance, the
longer the time.

(Jitter gurus correct this next part as necessary) If you have a pixel with
a value 0.0 in the starting frame and 1.0 in the ending frame it will take
longer to interpolate than te pixel pair 0.1-0.2. Different frames in the
same movie with take different times depending on the values of the pixels.
Frames that are similar arrive more quickly.

It’s akin to reverberation. If you set a reverb time of 2.0 seconds and
play a loud sound it will take longer to decay than a soft sound because the
process involves feedback.

Consider the following two sequences of numbers.

100 90 81 72.9 65.61 59.049 53.1441 47.82969 43.046721 38.7420489
34.86784401
50 45 40.5 36.45 32.805 29.5245 26.57205 23.914845 21.5233605 19.37102445

The first starts at 100% and decays by a factor of 0.9. At the 10th sample
it reaches approximately 1/3 of its original value. With same decay factor,
the second starts at 50% and reaches 1/3 around the 5th sample.

Cheers,
Gary Lee Nelson
TIMARA Department
Oberlin College
http://www.timara.oberlin.edu/GaryLeeNelson

Apr 22 2006 | 1:45 pm

it makes cells in jitter matrices nostalgic over time.

Apr 22 2006 | 2:40 pm

thanks ever so much! That makes more sense than the reference manual…

oh yeah, just one more question… What do the ‘y’, ‘n’ and ‘x’ represent in the formula: y(n) = y(n-1) + ((x(n) – y(n-1))/slide)?

Apr 22 2006 | 2:55 pm

take a look at the regular [slide] object first. consider this patch
i’m attaching and then consider this process numerical happening to
each and every cell in a jitter matrix.

best,
jonathan

the patch:

#P window setfont "Sans Serif" 9.;
#P flonum 141 419 80 9 0 0 0 3 0 0 0 221 221 221 222 222 222 0 0 0;
#P flonum 487 419 80 9 0 0 0 3 0 0 0 221 221 221 222 222 222 0 0 0;
#P flonum 405 419 80 9 0 0 0 3 0 0 0 221 221 221 222 222 222 0 0 0;
#P flonum 323 419 80 9 0 0 0 3 0 0 0 221 221 221 222 222 222 0 0 0;
#P flonum 241 419 80 9 0 0 0 3 0 0 0 221 221 221 222 222 222 0 0 0;
#P window linecount 1;
#P newex 487 93 61 196617 slide 100 0;
#P user multiSlider 487 118 26 262 0. 1. 1 2681 47 0 0 2 0 0 0;
#M frgb 10 255 9;
#M brgb 116 116 116;
#M rgb2 127 127 127;
#M rgb3 0 0 0;
#M rgb4 37 52 91;
#M rgb5 74 105 182;
#M rgb6 112 158 18;
#M rgb7 149 211 110;
#M rgb8 187 9 201;
#M rgb9 224 62 37;
#M rgb10 7 114 128;
#P newex 405 93 61 196617 slide 0 100;
#P user multiSlider 405 118 26 262 0. 1. 1 2681 47 0 0 2 0 0 0;
#M frgb 10 255 9;
#M brgb 116 116 116;
#M rgb2 127 127 127;
#M rgb3 0 0 0;
#M rgb4 37 52 91;
#M rgb5 74 105 182;
#M rgb6 112 158 18;
#M rgb7 149 211 110;
#M rgb8 187 9 201;
#M rgb9 224 62 37;
#M rgb10 7 114 128;
#P newex 323 93 61 196617 slide 50 50;
#P user multiSlider 323 118 26 262 0. 1. 1 2681 47 0 0 2 0 0 0;
#M frgb 10 255 9;
#M brgb 116 116 116;
#M rgb2 127 127 127;
#M rgb3 0 0 0;
#M rgb4 37 52 91;
#M rgb5 74 105 182;
#M rgb6 112 158 18;
#M rgb7 149 211 110;
#M rgb8 187 9 201;
#M rgb9 224 62 37;
#M rgb10 7 114 128;
#P newex 141 51 60 196617 loadmess 1;
#P toggle 141 73 15 0;
#P newex 141 93 52 196617 metro 10;
#P newex 241 93 61 196617 slide 10 10;
#P user multiSlider 241 118 26 262 0. 1. 1 2681 47 0 0 2 0 0 0;
#M frgb 10 255 9;
#M brgb 116 116 116;
#M rgb2 127 127 127;
#M rgb3 0 0 0;
#M rgb4 37 52 91;
#M rgb5 74 105 182;
#M rgb6 112 158 18;
#M rgb7 149 211 110;
#M rgb8 187 9 201;
#M rgb9 224 62 37;
#M rgb10 7 114 128;
#P user multiSlider 141 118 26 262 0. 1. 1 2681 47 0 0 2 0 0 0;
#M frgb 10 255 9;
#M brgb 116 116 116;
#M rgb2 127 127 127;
#M rgb3 0 0 0;
#M rgb4 37 52 91;
#M rgb5 74 105 182;
#M rgb6 112 158 18;
#M rgb7 149 211 110;
#M rgb8 187 9 201;
#M rgb9 224 62 37;
#M rgb10 7 114 128;
#P comment 41 228 100 196617 operate this one—>;
#P connect 1 0 17 0;
#P fasten 1 0 3 0 146 402 215 402 215 67 246 67;
#P fasten 1 0 8 0 146 402 215 402 215 67 328 67;
#P fasten 1 0 10 0 146 402 215 402 215 67 410 67;
#P fasten 1 0 12 0 146 402 215 402 215 67 492 67;
#P connect 11 0 16 0;
#P connect 9 0 15 0;
#P connect 7 0 14 0;
#P connect 2 0 13 0;
#P connect 3 0 2 0;
#P connect 8 0 7 0;
#P connect 10 0 9 0;
#P connect 12 0 11 0;
#P connect 6 0 5 0;
#P connect 5 0 4 0;
#P connect 4 0 1 0;
#P window clipboard copycount 18;

Apr 22 2006 | 3:31 pm

On Apr 22, 2006, at 9:40 AM, ed dowie wrote:

>
> Yeah. I read the help file and the reference manual entry, but I
> have to confess, didn’t quite understand them. Sorry to be really
> thick, but i guess i don’t really understand the formula:
>
> y(n) = y(n-1) + ((x(n) – y(n-1))/slide)
>
> I understand that there is a degree of feedback over time whose
> intensity of light/dark is controlled by slide_up and slide_down
> controls, but quite how it’s done is not quite clear yet!

Gary Nelson’s explanation does as good a job as any
of explaining what’s happening without making direct
reference to numbers. The object is performing the
calculation above on each individual plane/cell of a
movie; remember that the type of data that the calculation
is being performed on is arbitrary – I could be sending
it 1-plane matrices (or lists, to put it another non-Jittery
way), You’ll notice that the help file tells you that the
object supports all data types and planecounts. That’s
what that means.

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