[PD] emulating early video synths - sync

[Claude Heiland-Allen]

Hi Paris, all,

I've been experimenting with audio->video in Gridflow, see attached 
example patches, they're not brilliant but might give you some ideas. 
[#import~] is currently a (slow!!) abstraction I made, but maybe one day 
I'll learn enough C, C++, Ruby, and Gridflow internals to be able to 
make it a zillion times faster...


Here's some I made earlier:  </BluePeter>

http://claudiusmaximus.goto10.org/index.php?page=gallery/digital/CM-v-CM

(Stills from a DVD I'm working on, from time to time, it may even get 
finished one day...)  The corresponding audio is here:

http://www.archive.org/details/ClaudiusMaximus_-_Soft_Rock_EP

Working from pre-recorded audio meant I couldn't do anything easy to 
"sync" the frames and stop the "rolling", but I happen to like temporal 
aliasing a great deal - flickery trippiness is go!


The right inlet of an [osc~] or [phasor~] sets the phase between 0 and 
1, but only once (as you have found).  Here's a bonus tip:

  |
[mtof]
  |
[phasor~]
  |\
  | [*~ 1.5]  <<< vary this >= 1, maybe using an envelope
  |  |
  | [wrap~]
  |  |
[dac~]

...for that classic osc sync sound ;-)



Paris Treantafeles wrote:
> haha... i can't be the only one who has hit "send" then figured out  the 
> problem.
> 
> basically i wasn't really resetting the oscillators since sending a  
> number to the right inlet of the oscillator wasn't enough.
> once i added a metro and "banged" the input, the sync worked.
> 
> still... if there's anything that comes to mind regarding best block~  
> to use, please feel free to share.
> 
> best,
> p
> 
> 
> On May 4, 2006, at 11:48 AM, Paris Treantafeles wrote:
> 
>> Hello List,
>>
>> I've created a few patches with PD/GEM to emulate early video  synths 
>> such as the Sandin, etc. which I'm quite happy with.
>> At the heart of these patches is pix_sig2pix~
>> One thing I can't figure out though has to do with preventing the  
>> image from "rolling" - i.e. to stand still.
>> The early video synths did this by having a "sync" input to  oscillators.
>> So if you fed one oscillator a vertical sync (~60 Hz) you would get  
>> stationary vertical bars whose width would depend on the main  
>> frequency of the oscillator. Doing this with another oscillator  
>> receiving a horizontal sync (~1500 Hz) results in horizontal bars.
>> By mixing these and perhaps another (and adjusting the attenuation  of 
>> these), various shapes appear.
>> I can get all of this and more (e.g. add some filters for  subtractive 
>> synthesis) but what I'm missing is how to do the sync  correctly.
>> Trying various values as reset inputs to say "phasor~" doesn't do it.
>> I'm wondering if this is in fact related to blocksize~ instead.
>> e.g. should the reset values of the oscillators be related in  someway 
>> to the value set in blocksize~
>>
>> Does anyone have any ideas about this?
>>
>> Thanks for any suggestions!
>>
>> Best,
>> p
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