Glitch transitions

Glitch transitions

A glitch stinger hides a switch inside a burst of broken signal. For a fraction of a second the picture tears: horizontal slices jump sideways, the colour channels split (red one way, blue the other), rectangles break off and pixelate, and static washes over it. The burst peaks on the switch itself, so neither shot is readable on the frames around the cut, then falls away and leaves the new shot clean.

Load tella-transitions too, for when a transition is worth having. references/glitch.sksl is the shader; it is the look, so use its full text as is.

The presets

Hard crash also keys flash to 0.55 for one frame on the switch (a single pale frame). Between presets, scale the four numbers together; longer than 0.8 s or slice above 320 reads as a broken file, not a transition. Keep one preset per kind of switch across a video, and Hard crash for one or two moments at most.

amt is the envelope, keyed on 1/15 s steps with hold easing: a stutter in (up, back down, up), 1 on the frames either side of the switch, then a falling tail to 0. The tested Signal tear keys: 0.25, 0.55, 0.3, 0.8, 1, 0.9, 0.6, 0.35, 0.15, 0. Chroma blip is shorter (0.35, 0.8, 1, 0.85, 0.4, 0.15, 0); Hard crash holds 1 for two steps and has a longer tail. Smooth easing makes it a fade.

Ask first

From the timeline and transcript, list the candidate switches (b-roll starts and ends, layout changes, punch-ins, clip boundaries), then ask in one question, prefilled with what you found:

• Where: every b-roll change, every layout change, every clip boundary, or named moments.
• Intensity: one preset or a mix (Chroma blip on punch-ins, Signal tear on b-roll, Hard crash on the one chapter change). Default Signal tear.
• Sound: a glitch sound on each (default yes).

Skip the question if they have said all three.

The switches and the words

• A glitch covers an instant change. Set every layout change it covers to transitionStyle: "hardCut"; a spring move under a glitch reads as mush. Adding a time-ranged b-roll layout also creates the layout after it with spring, so set that one to hardCut too.
• Skip switches less than about 1 s after another (let it hard-cut and say so), and any in the first or last 0.3 s of the video.
• The audio is untouched, so a stinger can sit over speech, but its peak should land between words or on the first word of the new thought, never inside a name or number. If a switch is mid-word, offer to nudge it to the nearest gap within 0.2 s.

Building it in Tella Motion

Each stinger is its own overlay document, full frame, depth: "front", no overlay animation, starting at the switch minus the preset's switch point. Inside is one node: a full-frame fill shape coloured #00000000 with the shader added as a backdrop effect, so it filters the footage, b-roll, layout and lower overlays beneath. Set the preset uniforms, key amt (and flash), and bind seed to floor(time × 15) + offset so the pattern changes 15 times a second. No built-in effect does the slice tear (fx.chromaticAberration only splits outward from the centre), which is why it is a shader.

Build and check the first one, then duplicate_motion_document it for each further switch and re-bind seed with a new offset (0, 37, 74, …) so no two tear the same way. Name them in order ("Glitch 02: Signal tear").

A switch between two clips takes two documents, since an overlay belongs to one clip: part 1 on the outgoing clip, ending on its last frame, with the keys before the switch; part 2 on the incoming clip from 0, with the rest of the keys shifted back and a first key holding the value in force at the switch. Give part 2 a seed offset of part 1's plus the steps already played, so the pattern carries on. Overlays work on Tella Motion clips too, so a glitch can tear into a title card clip.

What was hit:

• addAdjustment in an overlay only sees the overlay's own layers, so the footage is untouched (faint static and nothing else). An adjustment layer does work inside a Tella Motion clip or b-roll that contains both shots.
• kind: "shader" is refused inside addAdjustment's effects; add the shape, then addEffect.
• Uniform paths on the backdrop shape have a doubled effect (…/effects/0/effect/effect/uniforms/<name>/…); take them from inspect_motion_node_properties.
• duplicate_motion_document with commands can return a null result although they applied; confirm with inspect_motion_node that the seed expression has the new offset.
• setEffect on a uniform keeps the keys. Changing the shader text means removeEffect and addEffect, then re-keying amt and re-binding seed.
• The shader scales by canvas height / 1080, so the presets hold at 4K and in portrait, but on 9:16 use Chroma blip or Signal tear; Hard crash's slabs read as a blank frame on a phone.
• Very dark footage shows the slices less: go one preset up or raise noise by 0.1.

Sound

Tella's curated cyber-glitch (912 ms) fits all three. Add it at each stinger's start, volume 0.5, 0.6 and 0.7 for the three presets, trimmed so it ends inside the clip. One sound for every stinger.

Check

One get_filmstrip per stinger, every 1/15 s (the seed step) from 0.2 s before it to 0.2 s after, plus the frame either side of the switch: clean picture 100 ms either side (no leftover static, colour shift or offset); it stutters in, peaks across the switch with both shots torn and neither readable, no black or empty frame (Hard crash: exactly one pale frame), no frame of the new shot before the peak, and the tail settles rather than snaps.

Keep flashes to a single frame at 0.55 or less and no more than two stingers in any 3 s, for viewers sensitive to flashing. Report each stinger's time, preset and what it covers.

Making it your own

• A brand-coloured split: mix the separated red and blue channels toward the brand's two colours.
• A clean "UI glitch": blocks 0, noise 0, slice 80. A dirtier VHS look: noise 0.3, rgb 40, slice 60.
• A glitch title: a Chroma blip on a title's entrance, so the words tear into place.