The hardest medium.
AI video is a shot machine, not a film machine. Every frame has to agree with the last about gravity, faces and physics — and the longer the clip, the more that agreement breaks down into morphing and warping. This class teaches why video is exponentially harder than images, and how to direct it like a shoot.
Explain the limits
Say why long, complex shots break — temporal memory.
Direct a shot
Prompt for camera, motion and physics, not just a subject.
Artifacts & rights
Warping, the uncanny valley, and unclear usage rights.
True or false?
"To make a 30-second AI video, you should ask for the whole 30 seconds in one long generation." True or false?
The state of AI video
The field is fast and specialised — no single best model, just a best one per shot. Clips are usually a few seconds, increasingly with native audio. Your real job is generating many short shots and editing them into a sequence — exactly like a film shoot. Version numbers turn over monthly, so learn what each lab is good at, not its current number.
Veo-class
Strong all-rounders, some generating synchronised dialogue and sound, not just silent footage.
Runway-class
Reference images, explicit camera control and character consistency — the studio-workflow favourite.
Kling-class
Cheap, high-volume iteration with lip-sync and native dialogue.
Luma / Pika-class
Physically-accurate motion and HDR (Luma); fast effects and lip-sync for social (Pika).
Why it's so hard
A still image only has to look right once. A video has to look right across time — every frame agreeing with the last. Two limits make this brutal.
Temporal memory
The model has limited memory of earlier frames. The longer the clip, the more it "forgets" — so faces drift, objects morph, and backgrounds warp.
Physics
It learned statistics of how pixels move, not actual physics. Water, hands, hair and reflections are where it most often breaks.
Artifacts aren't random — they're predictable. They grow with clip length and motion complexity. Short shots with simple motion stay coherent; long, busy shots fall apart. The Coherence Lab below lets you feel exactly that.
The coherence lab
Each tile is a "frame" of one clip. Push clip length and motion complexity up and watch later frames drift, warp and sprout artifacts as the artifact-risk meter climbs. Keep it short and simple to stay coherent.
Prompting motion
A video prompt directs a shot, not a subject. Build it from six slots, and the most controllable path is image-to-video — lock the look in a still, then add motion.
Six slots of a shot prompt
1 · Subject · 2 · Action (what moves, how) · 3 · Camera move & framing · 4 · Lighting · 5 · Style/lens · 6 · Physics + duration + aspect + "stable, no warping".
1. Lock a hero still (composition, character, wardrobe). 2. Upscale it. 3. Load as the start frame. 4. Describe only the motion. 5. Keep it short, generate several takes. 6. Select, upscale, edit. Shoot coverage; build the film in the cut.
A teaser in a day
A small collective needs a 20-second teaser for a community film night.
One long prompt
They asked for the whole 20 seconds at once. Faces morphed, the logo melted, hands turned to soup — unusable.
Short shots, then cut
They storyboarded 5 short shots, used image-to-video from locked stills with directed camera moves, generated several takes each, then graded and cut in an editor.
Coherence came from short shots and coverage, not luck. Before posting, they checked the model's commercial terms and avoided any real person's likeness without consent.
Scout the models
Video models move fast. Find which one fits a specific need and note its clip-length limit.
What to look up
"best AI video model for character consistency" · "image-to-video tool camera control" · "AI video clip length limit".
Direct a shot
Write one shot prompt using all six slots, then describe in one line how you'd assemble a 15-second piece from short shots.
Success rubric — tap to expand
Needs work: a bare subject and one 20s prompt.
Getting there: a decent shot prompt but no assembly plan.
Solid: six-slot prompt + a short-shots plan.
Excellent: a directed six-slot prompt with a stability note, plus a plan to generate coverage and finish in an edit with a unifying grade.
Quiz — 5 questions
Common mistakes
One long generation
Asking for the whole scene at once. Fix: short shots, assembled in an edit.
Over-described motion
Cramming five movements into one shot. Fix: one clear movement per shot.
Fresh text-to-video for continuity
Expecting a character to match across generations. Fix: image-to-video from a locked reference.
Shipping raw clips
No grade, no rights check. Fix: finish in post, grade to one look, clear the rights.
Shot machine, not film machine
Now that you can see artifacts grow with length and motion, how does that change what you'd attempt with AI video — and where you'd still want a real camera?
You understand video's hard limits and how to direct around them. Last stop: turning all these skills into real-world business value.