Camera feedback w/VC help please?

hello, i’ve just been able to set up my lzx again after a limiting year… but i am RUSTY.
please can someone let me know a patch for camera feedback using the visual cortex and the minimum of other lzx gear.
i’ve always used my vidiot for this purpose but it got plugged into a 9v psu and now won’t work (will i be able to get this repaired?)
I can’t work out the best way to get an image out onto a monitor, then film it with the camera back into cortex, then view the result on another monitor, or out to the blackmagic/laptop.
your time and help would really make this period festive for me!
cheers and best wishes all

1 Like

Welcome back to the party!

Bummer about your mishap with Vidiot. You should open a ticket with LZX to find out about getting it repaired.

A video camera/Visual Cortex/TV feedback patch:

  1. Plug RCA cable/s from camera into Input Decoder section on the bottom right left side of the VC. For composite video (carried on a single RCA cable, usually with a yellow plug) connect camera output into the top input with the green ring around it on VC. For component video (carried on three RCA cables, usually with green, blue, and red plugs) connect the camera output to the three inputs on VC with green RCA to VC input with green ring, blue RCA to blue ring, and red RCA to red ring. Once camera is connected to VC, verify that you have two green LEDs lit in the Sync Generator section on the top left of the VC. One for your format (NTSC or PAL) and one for the lock icon to show that the VC has successfully locked to the sync timing of the connected camera.

  2. Patch out of the Luma/RGB points of the VC’s Input Decoder. (Remember, if using composite video, the video image will be black and white to start with.)

  3. You have four options for patching out of VC to a monitor from the Output Encoder section in the bottom left side: Video 1, 2 for composite out, S-Video out, or YPbPR for component out.

  4. Point your camera at the monitor screen and adjust camera angle, and distance from the screen to influence feedback. Zooming in/out and focus can also influence feedback.

  5. To capture with Blackmagic, you can tap another one of the output options described in step three and send that into the BM device.

Good luck! :slight_smile:

4 Likes

thank you so much… did you mean in (1.) from camera into Input Decoder section on the bottom left side of the VC
(or into Ouput Decoder section on the bottom right side of the VC?)
I guess the former?

i want to generate some shapes with the prismatic ray etc (not external video source), display them on a monitor, point the camera at that and then pump that back into lzx for processing then see/record the different result separately on another monitor/device, without the original pre-feedback image.
So in my head it’s like, i need one output from vc to monitor but then a different output to display the same with camera feedback… does that call for another VC or a video mixer? or maybe the slider on the VC takes care of that? sorry for being dim and cheers for your patience.

i have a panasonic cctv camera with genlock and a canon camera that lzx camera guide says has genloc, tho i can’t find a socket for it… but my point in mentioning this is, do i need to make a genloc connection between camera and VC? if so, would that be sync input inside (currently chained to PR etc in my case)? the sync generator does have 2 lights lit anyhow :slight_smile:

glad it can be done anyway, i’ll get there, thank you for your time and help, best wishes

2 Likes

Regarding your Vidiot & the power supply mishap, it really depends on the circuit design of the internal electrics. There’s the classic “reverse diode protection” to prevent the standard eurorack power cable from frying a module if the cable is inserted the wrong way around. Regarding DC & AC PSUs, this is a whole level of detail I know only the basics of. If you didn’t see or smell smoke, that’s really good because nothing burned & if you’re really lucky, you may only have to replace a fuse. Fingers crossed that you’ve dodged a head-on collision.

@Z0NK0UT, surely Ed should get in touch with ye at LZX HQ.

2 Likes

To quote Tina Turner:
“You’re simply the best!”
Awesome step-by-step instructions :grin:

2 Likes

thank you so much… did you mean in (1.) from camera into Input Decoder section on the bottom left side of the VC
(or into Ouput Decoder section on the bottom right side of the VC?)
I guess the former?

Oops, I’ve always struggled with my left and right … edited above to read left side of Input Decoder. Good catch!

i want to generate some shapes with the prismatic ray etc (not external video source), display them on a monitor, point the camera at that and then pump that back into lzx for processing then see/record the different result separately on another monitor/device, without the original pre-feedback image.
So in my head it’s like, i need one output from vc to monitor but then a different output to display the same with camera feedback… does that call for another VC or a video mixer? or maybe the slider on the VC takes care of that?

To get to something like that, I don’t see a way without a second VC. I patched up something like what you describe like with two VC. And yes, to do this I needed to genlock my camera. Patch:

  1. System sync from VC1 RCA Video 1 RCA output to VC2 input.

  2. Camera sync from VC1 RCA Video 2 RCA output to camera genlock BNC input.

  3. Prismatic Ray into VC1 channel A top input with red circle around it.

  4. S-Video out from VC1 to TV1 input. TV1 is the monitor video output. This shows the patten from PR and is where you can rescan the screen with the synced video camera.

  5. Camera output into VC2 channel A top input with red circle around it. (My camera sends video sync out through a BNC connector and the cable can be converted to 3.5 mm with a slip on connection adapter.)

  6. Component RCA outs from VC2 to TV2 inputs. TV2 shows final output of rescanned monitor (which is displaying PR pattern)

NOTE: this arrangement doesn’t produce significant feedback. One could feedback Video 1 output back into the G and/or B channels of VC2s channel A inputs to get some feedback going. The first patch that I gave definitely gets much more feedback. I think what we’re bumping up against is my lack of hands on experience with Vidiot and the lack of a dedicated Luma/Monitor output on VC. There is Luma out on the VC Input Decoder, but if I run that straight into a TV monitor there is nothing on the display. This makes sense as that Luma output is the LZX patching standard and pre Output Encoder … in other words, not a valid signal for a monitor to display. I’m basing my Vidiot setup/understanding on this video:

There’s an older thread over on Muffs which may be of use to this conversation as well:

So to address your other question:

i have a panasonic cctv camera with genlock and a canon camera that lzx camera guide says has genloc, tho i can’t find a socket for it… but my point in mentioning this is, do i need to make a genloc connection between camera and VC? if so, would that be sync input inside (currently chained to PR etc in my case)? the sync generator does have 2 lights lit anyhow

The system sync can be shared by both the front and rear RCA jacks. If you want synced video that doesn’t roll, then the VC either needs to be synced to the camera by connecting the camera to the VC Input Decoder, or the camera needs to be synced to the VC by connecting the VC output to the camera genlock. It may be helpful to know what model camera you’re trying to do this with.

Let us know how it goes and share some results if you can!

Another thread, this time from FB which may be relevant:

1 Like

I didn’t see much in the thread about cameras, it was mostly focused on mixing. Is this the right one you wanted to link to?

Yup, that’s the one. No camera talk, but reckoned the mixing discussion might be useful.

1 Like

I can definitely imagine flying those faders (a sound engineering phrase) as a camera feedback patch is doing it’s magic is really important but I haven’t tried it with my LZX setup, been meaning to for a long time though since first pointing a camcorder at the screen and been blown away by the beauty of feedback :star_struck:
The idea in Steven’s thread is cool, using the 4 various TBC2 outputs and flying around with them! Actually a joystick is surely the obvious choice, no?

1 Like

Video Grip and Polar Fringe are really delightful video tools, especially when nudging feedback oscillations by hand. I love joysticks.

2 Likes

If you had a liquid tv you could use that as your alternative output/monitor since you can view any signal within the patch, not just a video output. Or you could use a cadet encoder as another output without having to drop the $ on another visual cortex. Or if you had a Vidiot, that could be another output. Or wait until 202x for ‘visionary mkii’ for some kind of new encoder. Orrrr the most hack of all… Try putting the output of the prismatic ray directly in to a video monitor. It just may work (assuming you’re using h sync on the vco).

3 Likes

Adding a Cadet Encoder might be the easiest option