What it does
Smears moving parts of the image into blocky trails, like a corrupted video that never gets a clean frame.
Compressed video stores very few complete pictures. Most frames only describe change: for each rectangular block of the image, a motion vector saying where its content came from, plus a small correction. Delete a keyframe and the decoder never gets told the scene changed, so it happily drags whatever was last on screen along the new scene’s motion. That defect became a style in the mid-2000s, when music videos elevated the smear into a language, and the hard rectangular macroblocks became its fingerprint.
The canon has two moves. Removing keyframes produces the smear: one shot’s motion dragging another shot’s pixels, the transition that never resolves. Duplicating motion frames produces the bloom: the same vectors applied again and again, so a gesture keeps flowing long after the gesture ended. Between them sits the texture that sells the look, the corrections rebuilding small patches of the true image inside the wreckage, and the sudden total cure when the next keyframe arrives.
Traditionally you got there by hex-editing files or tricking encoders, then re-encoding and praying, with every upload threatening to clean the glitch away. A live datamosh simulates the decoder instead: it measures the motion between frames with the same family of block matching real encoders use, then drags stale pixels along that motion deliberately. The wreckage becomes directable. How hard the smear drags, how long motion persists, how quickly the image heals, and when the clean frame arrives all become decisions instead of accidents.
Signature looks
I-frame drop
The classic transition smear: a new scene’s motion dragging the previous scene’s pixels across the cut that never happened.
Bloom
Motion applied over and over until it flowers. A turn of the head keeps turning, trails flowing long after the subject stopped.
Slow heal
Heavy smear with the true image rebuilding in scattered blocks, the picture fighting its way back through the corruption.
Try it on your own footage
This effect runs live in the Modulate editor, free with no signup — or start from the free tool page for a guided setup.
Common questions
What is datamoshing?
Datamoshing is the deliberate abuse of video compression, removing or duplicating the frames that carry motion data so the decoder drags stale pixels along new motion. The result is the signature blocky smear: moving parts of the image melt into trails while the rest waits for a clean frame that never comes.
What causes the datamosh look?
Compressed video is mostly motion vectors, not pictures: only occasional keyframes carry a complete image, and every frame between describes where blocks of pixels moved. Deleting a keyframe leaves the decoder applying new motion to old content, and duplicating motion frames applies the same movement repeatedly. Both failures show the codec’s rectangular block structure, which is the texture people recognize.
Do you have to corrupt a video file to datamosh it?
That was the traditional method: strip keyframes with a hex editor or a tolerant encoder, re-encode, and hope the platform you upload to doesn’t repair it. Simulating the decoder is the modern alternative: the same motion-dragging behavior runs live as an effect, fully controllable, with nothing broken on disk. That is how Modulate’s Datamosh effect works.
What is the difference between datamoshing and pixel sorting?
They are the two pillars of glitch art, but they break different things. Datamoshing is temporal: it abuses motion between frames, so it needs movement and lives in video. Pixel sorting is spatial: it reorders the pixels inside a single frame along lines. Datamosh smears time; pixel sort streaks space.
How do I datamosh my own footage?
In Modulate, drop your clip into the editor and add the Datamosh effect: it estimates the footage’s motion live and applies the smear, melt, heal, and reset behaviors as adjustable controls. It runs on any moving layer, stacks with VHS and CRT for a full degraded-broadcast setup, and exports without any file surgery.
Related effects
Pixel sorting
Sorts runs of pixels into glitchy streaks by brightness, hue, or saturation. The classic pixel sorting look.
VHS effect
The full worn videotape package: color bleed, static, dropouts, wobble, and tracking errors.
NTSC effect
The look of an analog TV broadcast: soft edges, color bleed, scanlines, and signal noise.
Slit-scan effect
Each pixel shows a different moment in time — a gradient or control map melts the image across recent frames for slit-scan, rolling-shutter, and time-displacement looks.