electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » Video synthesis and manipulation
Voltage Controlled Video Processing Modules
Post new topic   Reply to topic
Page 1 of 1 [19 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
creatorlars



Joined: Nov 26, 2007
Posts: 524
Location: Denton, TX
Audio files: 4

PostPosted: Sat Feb 02, 2008 11:57 pm    Post subject: Voltage Controlled Video Processing Modules
Subject description: Do they exist?
Reply with quote  Mark this post and the followings unread

I've come across a few people experimenting with voltage controlled analog video processing, but have been unsuccessful in finding much information on how to manipulate a video signal or schematics/circuits for anything similar.

I'm mainly interested in processing (hue, saturation, etc) and distorting (static and noise patterns) analog video signals with the LFO's and EG's of my synth modules.

I've got a couple of old video source mixers to experiment with, but before I do... I'd like to collect as much information as possible. Anyone know where to find schematics or circuits for this kind of stuff? Even just general information or datasheets on ICs that process video signals.
Back to top
View user's profile Send private message Visit poster's website AIM Address
Pehr



Joined: Aug 14, 2005
Posts: 1307
Location: Björkvik, Sweden
Audio files: 2

PostPosted: Sun Feb 03, 2008 1:32 am    Post subject: Reply with quote  Mark this post and the followings unread

RGB signals are analog. Those could be manipulated in a modular before sent to a TV Twisted Evil Very Happy
_________________
YouTube channel
flickr photostream
http://loxodrom.blogspot.com
http://www.garageband.com/artist/loxodrom
http://soundcloud.com/loxodrom
Back to top
View user's profile Send private message
creatorlars



Joined: Nov 26, 2007
Posts: 524
Location: Denton, TX
Audio files: 4

PostPosted: Sun Feb 03, 2008 1:52 am    Post subject: Reply with quote  Mark this post and the followings unread

Yep!! And I've got an early 80's tube-powered studio camera that sends out RGB video... I want to use this and a VCR as video inputs for live performances. I guess I need to learn more about how to manipulate a video signal, and what it contains...
Back to top
View user's profile Send private message Visit poster's website AIM Address
bugbrand



Joined: Nov 27, 2005
Posts: 843
Location: Bristol, UK
Audio files: 1
G2 patch files: 1

PostPosted: Sun Feb 03, 2008 6:00 am    Post subject: Reply with quote  Mark this post and the followings unread

I'd be very interested to get more into video worlds (but maybe time won't let me) - I did a lofi video mangler back in November which was really fun but a bit unstable (and I still don't have any documentation on it) - part was based on some very simple passive filtering from Karl Klomp's site and then I made a very wierd opamp feedback stage (breaking rules!) which'd melt the signal or send it spasming - I put a switch in to select between four different opamps 'cos each type would make things look different. TL071 would make the whites explode out, LM709 (cracklebox chip) would make all these interference lines... wierd!

There's a forum here which may be of interest too:
http://vidisynth.mediumrecords.com/forum/

I'm attaching a large pdf file for the Sandin Video Processing system though I can't remember exactly where I found it.. It is a BIG document! And they recommend building a BIG system!


Sandin_Video_Proc.pdf
 Description:
Sandin Video Processing System pdf (5meg)

Download
 Filename:  Sandin_Video_Proc.pdf
 Filesize:  5.7 MB
 Downloaded:  219 Time(s)


_________________
http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com
Back to top
View user's profile Send private message Visit poster's website
Danno Gee Ray



Joined: Sep 25, 2005
Posts: 1343
Location: Telford, PA USA

PostPosted: Sun Feb 03, 2008 7:56 am    Post subject: Reply with quote  Mark this post and the followings unread

Radio Shack used to sell simple video processors and enhancers. If you can find one, try replaceing the control pots on one with some vactrol circuits and have a ball.
Last edited by Danno Gee Ray on Sat Mar 15, 2008 4:04 pm; edited 1 time in total
Back to top
View user's profile Send private message
mistercooper



Joined: Jul 17, 2006
Posts: 62
Location: Seattle

PostPosted: Tue Feb 05, 2008 11:48 am    Post subject: Reply with quote  Mark this post and the followings unread

iirc, one of the hard parts is maintaining the sync signal, which is nowhere near audio bandwidth.
Back to top
View user's profile Send private message
CJ Miller



Joined: Jan 07, 2007
Posts: 371
Location: 127.0.0.1

PostPosted: Sat Mar 15, 2008 12:46 am    Post subject: Reply with quote  Mark this post and the followings unread

There definately have been analog video synths! I got turned on to analog video art in the late 1980s, way after it became a bit obscure. Public television stations used to show a lot of video art in the 1970s... Anyway, it is not easy to find much information on how it is done.

If you know which end of a soldering iron to hold and can understand analog audio synthesis then you already have some advantage over many of the trailblazers, who knew video but not electronics. And then one needs to know video. The biggest difference is not that video runs in the MHz range, it is that video signals are composite. In music, we get a voltage that varies in frequency and amplitude over time. But for video the horizontal sync, vertical sync, and picture data are all lumped together. B&W is easier because the picture is just a varying level. Color packs more data. So the first useful things to figure out are how to strip the sync from picture signals. Then you can put the picture through whatever you want. And then make sure it has proper sync when it leaves so it can work on a regular TV, VCR or whatever. Luckily it is easy to find info on these kinds of circuits because they are commonplace in video electronics.

I'm dropping the bomb here. There is more information on video synthesis here than anywhere else on the web:
http://www.vasulka.org/archive/
Enjoy! It took me weeks to read it all, and months later I am still trying to digest what I read. Lots of info on the ins and outs of video. And there are schematics for the Paik-Abe, Sandin, and others. Most of these synths used ICs which are long obselete though, so the schematics are probably more for educational value of the principles than anything else. It is an amazing resource.

I wish you luck. I am still stuggling to finish four years worth of audio PCBs into a working synth. Still I really look forward to playing with video soon also.
Back to top
View user's profile Send private message
toppobrillo



Joined: Dec 10, 2005
Posts: 766
Location: oakland, ca
G2 patch files: 1

PostPosted: Sat Mar 15, 2008 2:11 am    Post subject: Reply with quote  Mark this post and the followings unread

Quote:
I'm dropping the bomb here.


you certainly have. thanks very much, i am going to be up all nite Shocked
Back to top
View user's profile Send private message Visit poster's website
bugbrand



Joined: Nov 27, 2005
Posts: 843
Location: Bristol, UK
Audio files: 1
G2 patch files: 1

PostPosted: Sat Mar 15, 2008 2:22 am    Post subject: Reply with quote  Mark this post and the followings unread

Awh, I dunno whether to even look at the link!
For interest, I've noticed that Futurlec have quite a few video ICs like:
http://www.futurlec.com/Linear/LM1203N.shtml - RGB video amp
http://www.futurlec.com/Linear/LM1881N.shtml - sync separator
http://www.futurlec.com/Linear/NE592N.shtml - differential video amp
etc
---- too much to get sucked into right now (and ever?!)

_________________
http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com
Back to top
View user's profile Send private message Visit poster's website
Clack



Joined: Aug 08, 2005
Posts: 436
Location: Seven Sisiters - london
Audio files: 5
G2 patch files: 1

PostPosted: Sat Mar 15, 2008 12:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

is this the kind of thing you have in mind ?

http://matrixsynth.blogspot.com/2008/02/5-minute-romp-thru-ip.html

this fascinates me

_________________
Clacktronics.co.uk
Back to top
View user's profile Send private message Visit poster's website
Danno Gee Ray



Joined: Sep 25, 2005
Posts: 1343
Location: Telford, PA USA

PostPosted: Sat Mar 15, 2008 4:15 pm    Post subject: Reply with quote  Mark this post and the followings unread

Does anybody have schematics for that kind of stuff?
Back to top
View user's profile Send private message
creatorlars



Joined: Nov 26, 2007
Posts: 524
Location: Denton, TX
Audio files: 4

PostPosted: Sat Mar 15, 2008 11:00 pm    Post subject: Reply with quote  Mark this post and the followings unread

That link is great, thank you... man, yeah, little sleep for me...

Wow, good timing for this thread to become active again!

I just last night stayed up REAL late working on some video-related experiments. I've got a couple of 1980's video FX units (just hue/saturation/contrast adjusters basically) that I'm in the process of making voltage controllable. I've had great luck w/the hue and saturation especially so far... but haven't got it tweaked perfectly yet. I also made a basic passive panel w/audio inputs and pots ala the schematic on Karl's site. Have gotten some very interesting, predictable effects, especially with LFO's with audio-->video modulation, but it mainly seems to be screwing w/the sync signals rather than color information.

I also started playing with the dozens and dozens of adjustment trimmers inside my Ikegami tube video camera. Voltage control of the camera itself could yield some CRAZY results. (My act uses a live camera feed for projections at shows.) Or even just filmmaking... live soundtrack-controlled cameras anyone?

I want to be able to split the image into several value ranges and manipulate each separately in a modular/patchable fashion, like Sandin's IP. I've studied those schematics briefly, but finding modern IC equivalents is definitely neccesary... I have a feeling the obsolete encoder board he refers to is something that can be ripped out of a cheap video unit or camera very easily these days, or may be available in IC form.

Thanks for the futurlec links. One of the video fx boxes I mentioned uses the LM1881N. Unfortunately I haven't found schematics for either of these boxes.

We'll see how things develop, it's a shame no one's developed more material here in a Synth DIY fashion.
Back to top
View user's profile Send private message Visit poster's website AIM Address
snufkin



Joined: Apr 06, 2007
Posts: 55
Location: the world

PostPosted: Sun Mar 16, 2008 3:29 am    Post subject: Reply with quote  Mark this post and the followings unread

i have been wanting to make a small video synth for ever

i found this ages ago which kinda got me thinking

(hope no one has already posted)


http://www.audiovisualizers.com/toolshak/vsynths.htm
Back to top
View user's profile Send private message
toybox



Joined: Aug 03, 2005
Posts: 176
Location: chicago/peru,illinois usa

PostPosted: Sun Mar 16, 2008 6:28 am    Post subject: Reply with quote  Mark this post and the followings unread

found this one awhile ago always looked like a lot of fun
http://www.mediumrecords.com/vs0/vs001.html

_________________
mY MusIc
http://www.myspace.com/toyboxbastard
Back to top
View user's profile Send private message
creatorlars



Joined: Nov 26, 2007
Posts: 524
Location: Denton, TX
Audio files: 4

PostPosted: Mon Mar 17, 2008 7:52 am    Post subject: Reply with quote  Mark this post and the followings unread

Yeah, I wish there were full schematics for that VS001 available.

One of those Futurlec IC's, the LM1203N, looks like it could definitely be implemented w/voltage control as an RGB controller module. Just need some kind of Composite-->VGA circuit, which I'm not having much luck finding.

I'm not really interested in video-synths so much as voltage-controlled analog video manipulation from camera/VCR sources. I want the keying and amplitude classifying capabilities of something like the Sandin, which you won't get with just voltage-control of Red/Green/Blue/Brightness/Contrast. I really wish I knew what I was doing enough to find replacements for the two IC's used throughout the Sandin IP... the MC1445 and CA3030 (these are nowhere to be found, but I'd be willing to buy lots of 50 pieces each if I could find them anywhere.) If I were to try to redocument and do board layouts for the Sandin, though... I'd want to try to find IC replacements still in production. It looks like a lot of the more complex Sandin IP boards could be replaced by chips (Sync Separator, Color VGA-->NTSC Encoder, etc.) If anyone's interested in giving me a hand trying to find workable replacements for those ICs, lemme know. It's probably right under my nose...
Back to top
View user's profile Send private message Visit poster's website AIM Address
creatorlars



Joined: Nov 26, 2007
Posts: 524
Location: Denton, TX
Audio files: 4

PostPosted: Mon Mar 17, 2008 10:15 am    Post subject: Reply with quote  Mark this post and the followings unread

I found this one...

http://cgi.ebay.com/NTSC-to-RGB-Converter-Hook-up-Consoles-MAME-to-JAMMA_W0QQitemZ170199208069QQihZ007QQcategoryZ13718QQtcZphotoQQcmdZViewItem
Back to top
View user's profile Send private message Visit poster's website AIM Address
TheAncientOne



Joined: Dec 26, 2006
Posts: 146
Location: United Kingdom

PostPosted: Thu Mar 20, 2008 7:44 pm    Post subject: Reply with quote  Mark this post and the followings unread

"The Daddy" of all analogue video synths was the EMS "Spectron". I saw one once as youngster and wanted it!

http://members.tripod.com/werdav/spectron.html

The Spectron is probably unclonable - it needs about half an acre of Ghialmetti patchboards for a start.

The Sandin is probably still do-able. For me, I'd have to change a lot of the I/O and timing because I'm in Europe, and the analogue video standard is not NTSC, (said by techs to stand for "Never Twice Same Colour"). but PAL, with a higher line count, (625 not 5252) and a lower frame rate, (50Hz not 60Hz).

I think a lot of the obsolete logic and counter chips could be mashed into PAL's or CPLD's. I'd do the standard video amps as neat little surface mount modules with 4 pins, and treat them as a chip.

It would be a way cool project - and there is lots of old analogue video gear floating around due to the move to HighDef.

Mr Bugs: I'm coming down to see a friend in your area next week, I hope. Perhaps we should meet up and plot....

_________________
Mike
Back to top
View user's profile Send private message
bugbrand



Joined: Nov 27, 2005
Posts: 843
Location: Bristol, UK
Audio files: 1
G2 patch files: 1

PostPosted: Fri Mar 21, 2008 2:48 am    Post subject: Reply with quote  Mark this post and the followings unread

TheProf wrote:
"The Daddy" of all analogue video synths was the EMS "Spectron". I saw one once as youngster and wanted it!

http://members.tripod.com/werdav/spectron.html

The Spectron is probably unclonable - it needs about half an acre of Ghialmetti patchboards for a start.

The Sandin is probably still do-able. For me, I'd have to change a lot of the I/O and timing because I'm in Europe, and the analogue video standard is not NTSC, (said by techs to stand for "Never Twice Same Colour"). but PAL, with a higher line count, (625 not 5252) and a lower frame rate, (50Hz not 60Hz).

I think a lot of the obsolete logic and counter chips could be mashed into PAL's or CPLD's. I'd do the standard video amps as neat little surface mount modules with 4 pins, and treat them as a chip.

It would be a way cool project - and there is lots of old analogue video gear floating around due to the move to HighDef.

Mr Bugs: I'm coming down to see a friend in your area next week, I hope. Perhaps we should meet up and plot....


Nice one Mike - PM'ing you..

_________________
http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com
Back to top
View user's profile Send private message Visit poster's website
creatorlars



Joined: Nov 26, 2007
Posts: 524
Location: Denton, TX
Audio files: 4

PostPosted: Fri Mar 21, 2008 7:53 am    Post subject: Reply with quote  Mark this post and the followings unread

Wow, yeah the Spectron looks amazing! Smile

I am a film school grad so I'm familiar with all the NTSC/PAL stuff (not that they taught us anything about actual video equipment, hah.)

Anyway, I found the MC1377... this chip is exactly what I was looking for, and an NTE replacement is still available from Mouser for $6. It is an RGB-to-NTSC/PAL encoder and can be used to generate all the necessary standard sync/blanking, etc. I think this was used in the Commodore. There are probably some surface-mount modern equivalents.... but the difference between PAL & NTSC is a simple matter of connecting a pin to ground!! Smile

With a few "input modules" to filter out the sync, and an output module based around the NE1203 (RGB Amplifier System IC from Futurlec) + the MC1377, you've got the potential for a pretty damn complex "Voltage Controlled Video Enhancer/Colorizer"... and then adding redesigned clones of the logic/processing modules in the Sandin should be fairly straightforward. They only use two ICs, one as a 4-quadrant multiplier and the other as a standard wideband op-amp.

What's gonna happen if I use a normal op-amp w/video (like the TL072)? Is there just going to be a quality decrease?
Back to top
View user's profile Send private message Visit poster's website AIM Address
Display posts from previous:   
Post new topic   Reply to topic
Page 1 of 1 [19 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Video synthesis and manipulation
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use