Problem with high-speed movement

I’m using VVVV to control a line of LEDs, sweeping a white square horizontally across the renderer which is then sent to a Video Micro Converter and converted to E:Pix (DMX). The LEDs should show a very fast stream of light going from right to left.

LFO > Map > Transform > Quad > Renderer EX9 > DVI > VMC > LEDs

Even at speeds of only 7Hz (period of 0.14 on the LFO) , gaps appear between the LEDs which shows something in the signal chain isn’t keeping up/frames are being dropped. I’d like to get up to speeds of 20Hz, but this is not possible, as the signal becomes more and more broken.

Any ideas what could be causing this?

i assume that you have a hardware problem.
did you try another DVI source?

how many leds do you control? maybe it’s better to create DMX with vvvv itself.

anyway it may be worth a try to play around with renderer’s “hidden” parameters. maybe you have to change the refresh rate or presentation interval? but honestly i don’t think so

bypass dmx hardware DVI converter and try with pippet EX9 and artnet sender node ?

OK, the initial post was more to do with debugging the actual problem. Here’s the patch.

What we’re actually trying to do is sweep a picture over a vertical line of LED Pixels about 20 times per second. This would be a period of 0.05s on the LFO, but once we get down past 0.3s we start seeing the stream break up (it’s easier to see horizontally, that’s why I asked about that first) on the LEDs, and on the computer monitor as well.

We’ve increased the rate of the DMX-Signal (we’re actually using E:Pix which has more DMX channels and is faster)which improved the situation, but we still can’t get as fast as we want.

Kalle: There are 60 LEDs in a line, and sending DMX from vvvv direct didn’t help. We’ve also tried changing the renderer’s parameters to no avail.

karistouf: I couldn’t get my head around the pipet EX9, but it seems it’s only representing one pixel at a time? How do you output a 80x60 Pixel picture with that?

The patch is really simple, but something is causing the signal to lag. Any help much appreciated! Thanks kalle and karistouf already!

LED_hin_her_6.3.v4p (9.2 kB)

very quickly and dirty the pipet sample …
normally with pipet you will go FASTER. especially hiding the renderer.

DVI: sure you dont have a trouble with frequency of your graphic card ?
to wich frequence can you go up with it ?

and are you sure about your leds ? wich model, what is behind (dmx pwm etc) ?

Pipet (EX9.Texture) help.v4p (13.7 kB)

OK I update the graphic card driver, and set it to 75Hz instead of 60Hz. Gained a bit of speed, which produced better results - but not good enough! ;)

The LEDs should be fine, they came straight from Traxon (60 Pixel Tube). They’re controlled with e:pix (a faster, higher channel version of DMX).

I’ll try to set up the patch with pipet instead of the renderer and see how that goes.

Thanks for the help so far…

All I get with the pipet is the color of one pixel. How do you get all of them like in the info patch?

OK, got my picture to appear in the pipet. Now, how do I get it to move with an LFO?

If your animation is the first patch:
Connect a dx9texture node to the output of the renderer: this will be your texture to feed in pipet

75hz: hum, better to go to 100hz
This plus surely dvi transcoding is surely issuing your troubles

Have you got other dmx interfaces ( artnet or enttec pro)?
It would be great to give it a try and see differences with your dvi based solution

I’ve got the renderer connected to the pipet through the dx9 texture now. Without the renderer window I can get up to 100 Frames/s on the Timing node.

Graphics card only goes up to 75 Hz unfortunately.

I swapped DVI cables - now the VMC is being fed with Dual Link, the Monitor with Single Link, and I believe that has made a difference.

We’re getting closer. Will see if we can get another interface happening…

nickluckman have you tried setting the Mainloop node to something ludicrously high? Also, check out the Boost node.

if so, no other way than pipetting …
maybe this could be the good occasion for a new plugin ?