[sdiy] Video-synth DIY ?

[Robert Roesler]

I have a pdf copy of Dan Sandin's IP documantation that I downloaded from
somewhere a couple of years ago. A cursory google search didn't turn the
original location up.

As far as I can tell, it is, and always has been, in the public domain.
According to Dan (page 5):

start quote {
DISTRIBUTION RELIGION

THE IMAGE PROCESSOR MAY BE COPIED BY INDIVIDUALS AND NOT-FOR-PROFIT
INSTITUTIONS WITHOUT CHARGE. FOR-PROFIT INSTITUTIONS WILL HAVE TO NEGOTIOATE
FOR PERMISSION TO COPY. I THINK CULTURE HAS TO LEARN TO USE HIGH-TEK
MACHINES FOR PERSONAL AESTHETIC, RELIGIOUS, INTUITIVE, COMPREHENSIVE,
EXPLORATORY GROWTH. THE DEVELOPMENT OF MACHINES LIKE THE IMAGE PROCESSOR IS
PART OF THAT EVOLUTION. I AM PAID BY THE STATE, AT LEAST IN PART, TO DO AND
DISEMINATE THIS INFORMATION; SO I DO.
} end quote

If anyone here is interested in putting it up on their site, I would pass it
on. Otherwise, if individuals are interested, I will forward it to them.

-Bob

p.s. Note in advance that key parts fro the IP's construction are long
obsolete (to the best of my knowledge)

On 06/28/2005 9:32 AM, "Tony Clark" <clark at andrews.edu> wrote:

>    Hi CJ,
> 
>> Does/ has anybody here tinkered with making video synths or processors?
> 
>    I have dabbled just a tiny bit...  :)  I too have a huge interest in
> video synthesis, if nothing more than for audio visualization.
> 
>> I am aware that video signals run faster, with the various components
>> synchronized together. What I have read on the topic at
>> AudioVisualizers and other sites is not terribly specific about
>> implementation. A lot of the older systems (circa 1968-1974) appeared
>> to be analog modular (audio) synths which had interfaces hacked into
>> video scan modulators, ramp generators, etc. Lots of emphasis on
>> oscillators being "phase locked", which I'd guess is like hard sync?
> 
>    The concept is very similar to audio synthesis, but there are some
> distinct differences.  First, as you mentioned, everything runs much
> faster and is typically synced to a master clock.  Actually, there are
> two distinct clocks, vertical and horizontal refresh rates.  You can also
> have a pixel clock, but these run _really_ fast and need special care to
> avoid EMI issues.  But really depending on what effect you are after,
> you'll use a combination of both horizontal and vertical refresh clocks
> to time everything with.
>    Another difference from audio side is that the circuitry needs to be
> free of temperature drift.  This would mean that linear oscillators (or
> phase accumulators) would be preferred over the expo type in normal
> modulars.
> 
>> Thinking ahead, since I will have a few panels together this year, I am
>> wondering how I can interface these to video gear. My computers are not
>> fast enough for most video stuff I have tried, and I am less inspired
>> by the After Effects and Arkaos ways of doing things. NATO or Jitter
>> would be fun, but are too expensive for me now, and I'd need a faster
>> computer. So I am determined to learn more about video synth DIY. I
>> currently have way too much stuff on my plate to fix, mod, and build -
>> so I will start messing around with this stuff next year.
> 
>    It's not difficult to interface to things such as a VGA computer
> monitor, but is definately trickier to interface to a TV (NTSC/PAL).
> Timing is everything and there are too many standards, unfortunately!
> 
>> I'd be more than psyched to hear of anybody's experiences with such
>> things!
> 
>    I hope to have something to show later this year, but currently I have
> to get a contract manufacturing job completed first before I can devote
> any time to it.
>    BTW, I would be highly interested in any schematics or information
> about classic video synths.  I've scoured the net and haven't really
> found much...
> 
>    Cheers,
> 
>    Tony
> 
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