The decoder’s own failure, simulated live: motion in your footage drags stale pixels along it, with smear, melt, and heal under your control.
How to use it
- Open the editor from this page — it loads a demo clip with the mosh already running — then drop in your own footage. Datamosh is made of motion, so it needs video, not a still.
- Dial in the glitch: smear strength, melt (how long motion persists), block size, and heal rate.
- Set how often a clean frame cures the image, press play to watch the smear accumulate, then export an MP4.
What the datamosh effect actually does
Classic datamoshing breaks a video file so the decoder misbehaves: delete the keyframes and it drags stale pixels along the motion of new footage. This tool simulates the decoder instead of corrupting a file. It measures the motion between frames with hierarchical block matching, the same family of search real encoders use, then displaces the previous frame along those vectors in hard rectangular macroblocks. Heal re-anchors scattered blocks to the true image the way codec corrections do, and the reset interval plays the role of the keyframe that finally cures the picture.
Because the wreckage is simulated, it is directable: smear can be overdriven past the measured motion, melt keeps vectors flowing after the subject stops moving, and none of it depends on an encoder cooperating. The same Datamosh effect ships in the Modulate editor, where it stacks with VHS, CRT, and pixel sorting for a full glitch chain and every parameter can be keyframed.
Common questions
Is this datamosh tool free?
Yes. This page opens the full Modulate editor, free with no signup, with the effect already set up. Anonymous exports run up to 5 seconds at 1080px with a small watermark; a free account removes the watermark and raises exports to 1920px and 30 seconds, and Pro raises the caps to 4K and 5 minutes.
Why does the effect need video?
Datamosh is temporal: the smear is built from motion between frames. A still image has no motion to measure, so there is nothing to drag. Any clip with movement works, and the harder the motion, the harder the smear.
Will the glitch survive uploading to Instagram or TikTok?
Yes. Traditional datamoshing lives in a corrupted file, and platforms re-encode every upload, which repairs the damage. This effect bakes the smear into the pixels themselves, so it survives any re-encode.
Can I datamosh a transition between two clips?
Yes. The editor this page opens handles the classic keyframe-drop transition: stack two clips in sequence, add the Datamosh effect above them, and the smear carries the first shot into the motion of the second.
Are my files uploaded to a server?
No. The motion analysis and the smear both run in your browser on your GPU. Your footage never leaves your computer unless you save it to a Modulate project yourself.
Go deeper
Datamoshing
Datamoshing is a glitch technique that breaks the motion side of video compression: the decoder keeps applying fresh motion to stale pixels because the clean keyframes that would correct them are gone. Moving subjects smear into blocky trails, stopped motion keeps flowing, and the image only recovers when a new keyframe finally lands. It is the most cinematic glitch there is, because it is made of the video’s own movement.
Pixel sorting
Pixel sorting rearranges the actual pixels of an image along straight lines: contiguous runs of pixels that pass a brightness test are reordered by brightness, hue, or saturation, so each run becomes a smooth ramp and the image appears to bleed into streaks of light. Nothing is added and nothing is lost, every pixel survives in a new position, which is why sorted images keep an unmistakably photographic grain inside the abstraction.
VHS effect
The VHS effect makes digital video look like it was recorded and played back on tape: soft resolution, a wobbling image, tracking bands that tear across the frame, color that lags and bleeds behind the brightness, dropouts, and noise. Every one of those artifacts has a physical cause in the tape or the player, which is why a convincing VHS effect is a simulation of the machine, not a scanline overlay.
There's more where this came from
The full editor lets you use every effect together, over video, text, 3D, and shapes. Free, no signup, nothing to install — it opens with this effect already set up.
Open the editor