Technique

Video Feedback

Video Feedback

Video feedback loops are one of the purest, most “alive” glitch art techniques: you take a camera, point it at its own display, and let the system mutate itself into endless geometry, bloom, and noise.

What is a glitch art video feedback loop?

A video feedback loop is created when a camera captures a display that is showing the live signal from that same camera. Each frame is:

  1. Captured by the camera
  2. Displayed on a monitor or projector
  3. Recaptured again by the camera

This closed circuit repeats in time, so small changes are re-amplified across frames, generating spirals, tunnels, fractals, and fluid “reaction-diffusion” textures.

In glitch art, this once-unwanted “technical flaw” is treated as a generative system: a self-mutating image synthesizer built from nothing more than a camera, a screen, and light.

How video feedback works (core mechanics)

At the heart of video feedback is delay and accumulation:

  • There is always a slight time lag between capture and display (camera processing + display refresh).
  • Each new frame is a slightly “older” version of the last, so shapes are repeatedly transformed and layered.
  • Bright areas add up over time, becoming more intense, while dark regions tend to stay stable or “drop out”.

Key physical and signal factors:

  • Frame rate & processing delay: Longer delays create more visible “echoes” and flowing motion.
  • Display type:
    • CRTs give softer, analog-looking warps.
    • Digital displays add sharper geometry and moiré, with extra delay that enhances line structures.
  • Optics & alignment: Zoom, focus, angle, and distance define the tunnel shape, vanishing point, and symmetry.

Think of it as “a photo of a photo of a photo” taken many times per second, but with each iteration slightly shifted and transformed.

Basic setups and tools

Minimal “camera into screen” rig

You only need:

  • A camera (camcorder, CCTV, webcam, phone with HDMI out)
  • A display (CRT TV, LCD, projector)
  • One video cable or capture route from camera to display

Basic patch:

  • Camera output → Display input
  • Point camera at the display
  • Adjust until you see the repeating “tunnel” effect.

Analog vs digital flavors

  • Analog camera + CRT

    • Classic soft, organic feedback.
    • Great for glowing blobs, spirals, nebula-style forms.

  • Analog camera + digital display

    • Extra delay introduces fine reaction-diffusion lines and sharp patterns.

  • Internal / no-input feedback

    • Use a video mixer or software loop: output routed back into input with slight parameter changes each pass.
    • Behaves like feedback without a physical camera, ideal for integration with other glitch sources.

Optional tools

  • Video mixers / “dirty” mixers: Let you mix clean camera feedback with other sources, key layers, and add extra distortion.
  • Glitch devices & enhancers: Route the feedback signal through circuit-bent gear, color correctors, TBCs, or glitch boxes before it returns to the display for hybrid analog–digital chaos.
  • Software (e.g. VJ apps, Syphon loops): Create software-only feedback by routing a window or texture back into itself with transformations each pass.

Core techniques

Once your loop is stable, small moves have huge impact:

  • Camera position & angle

    • Centered, straight-on framing gives infinite tunnels and central vortices.
    • Tilt or rotate slightly for spirals, kaleidoscopic diagonals, and drifting galaxies.

  • Zoom & focus

    • Zoom in to push the vanishing point offscreen and exaggerate curves.
    • Defocus for soft, cloud-like energy masses; sharp focus for crisp, latticed geometry.

  • Lighting & objects

    • Shine colored lights, LEDs, or use gels to seed the loop with chromatic structures.
    • Place hands, shapes, text, or reflective objects between camera and screen; everything entering the frame is “captured” into the evolving pattern.

  • Contrast & brightness

    • High brightness makes feedback blow out into hot halos and flares.
    • Lower levels preserve detail and keep the loop from saturating too quickly.

  • Signal processing in the loop

    • Color phase shifts, hue cycling, mosaics, and dithering reshape each iteration, turning simple feedback into structured visual synthesis.

Practical tips for stable, expressive feedback

  • Start simple and dial up

    • Get a clean loop working before adding mixers, glitch devices, or software effects.

  • Lock down your hardware

    • Use a tripod. Tiny bumps radically change the image, which is good creatively but bad if you are trying to repeat a look.

  • Avoid runaway brightness

    • If the whole frame turns into a white blob, lower display brightness and camera gain; remember that bright values accumulate every frame.

  • Exploit the edges

    • Many interesting structures form at the borders, where the screen just barely fits in the frame. Nudge framing millimeters at a time.

  • Capture at the source

    • Record from the mixer / camera output or via a capture card to avoid extra compression artifacts you do not want.

  • Treat it as performance

    • Feedback is live, temporal sculpture. Practice smooth parameter “gestures”: slow zoom pulls, gradual angle shifts, rhythmic light changes.

  • Document your patches

    • Note which camera, display, distance, and settings produced a given look. Feedback is sensitive: documentation is key to building a personal vocabulary.

Used intentionally, video feedback loops turn the most basic imaging circuit into a reactive, improvisational glitch synthesizer that never outputs the same image twice.