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jit.peek~ analysis

September 23, 2009 | 4:05 pm

I’m making a Video to Audio project, and I’m using jit.peek~.

As it says in the help file, jit.peek~ reads matrix data as an audio signal. But how?

The third argument is for the plane, so it only analyze one of the tree RGB planes separately.

But how does this process works?

After some audio tests, I found this to be probably true:
jit.peek~ recognizes the color amount of one plain, and translates this to the amount of harmonics. The more color of a certain plain, the more harmonics one can listen to.

Am I correct? If not, please explain why.
Thank you all, and happy patching!


September 24, 2009 | 8:43 pm

jit.peek~ simply reads the value of one plane’s cell of a matrix, and converts it to an audio signal. which cell is read is determined by the audio signal inputs to jit.peak~.

color and harmonics have nothing to do with it. it’s all just numbers.

perhaps if you provide a patch, which illustrates what is not clear, we will be able to provide further explanation.


September 28, 2009 | 6:17 pm

As I understand (please correct me if I’m wrong) from the help patch, the inputs of jit.peek~ determines the values for each dimension. In this case, X and Y. The number of dimensions are determined by the second argument. So, if the number is 3, we have 3 dimensions (which is odd to me, since a movie only has 2 dimensions. What would be the 3rd? And the 4th?).

jit.peek~ analize a single pixel, or a whole plane?

As I see, for example, green increasing in the movie, jit.peek~ changes the sound. What is this change? Is it frequency, is it harmonics? What numbers are these, and where are they from?

Here is a changed help max patch that I’m trying to understand:

– Pasted Max Patch, click to expand. –

…any help is truly apreciated. Thanks!


October 1, 2009 | 11:43 am

I was fooling around with jit.peek~ for several days…

Tried different dimensions, besides (x,y), and they seem not to work…

I understand that the 1st two audio signals define the X and the Y of a single plane of the movie, but if one changes the phasor to other oscilator, it changes the sound.

What is happening, regarding DSP?
Is this a sum or multiplication os signals? What kind of synthesis is this?

please help…


October 1, 2009 | 5:06 pm

you are still trying to impose some abstract meaning on the matrices and signals that might be causing your confusion. both the input (matrices) and the output (signals) to jit.peek~ are numbers.

if the input matrix is one or two dimensional, and one to four planes (as in the help file), it is easy to view that data as color information by plugging it into a jit.pwindow. but it doesn’t have to be constrained or interpreted that way.

the output is just a signal vector representation of the input. no frequency, no harmonics, no synthesis, just numbers directly pulled from the input matrix. whatever you do with that signal before sending it to your speakers (if that’s the intention) is up to you. in the help file, one row of one plane of a 2D 4 plane matrix is read by peek, multiplied, and played back.

check out Max5/examples/jitter-examples/audio/ for further examples. hope this helps.


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