Choosing an AI video generator
How to compare AI video models on the axes that matter — motion realism, native audio, image-to-video fidelity, duration and cost per usable clip.
Video models differ more from one another than image models do, so "which is best" has an unusually job-dependent answer. These are the axes worth testing.
Six axes that separate video models
| Axis | Question it answers | Matters most for |
|---|---|---|
| Motion realism | Does movement have weight and momentum? | Anything with people or physical action |
| Native audio | Is sound generated with the picture? | Dialogue, ambience-led scenes |
| Image-to-video fidelity | How faithfully does it animate a supplied still? | Brand and product work |
| Temporal stability | Does the subject stay itself across the clip? | Longer shots, character work |
| Prompt adherence | Does it follow a brief or improvise? | Work with a spec to hit |
| Cost per usable clip | Attempts needed before a keeper | Everything, and it is usually decisive |
Cost per usable clip is the real metric
Published price per generation is misleading. What matters is how many attempts you need before you have something you would actually deliver. A model at half the price that needs four attempts costs twice as much as the expensive one that works on the second. Track keepers, not runs — most people discover their intuition here was wrong.
A comparison you can run yourself
- Pick one shot you genuinely need, not a demo-friendly one.
- Generate the starting frame once and reuse it across every model, so you are testing motion rather than composition.
- Run each model three times on the same prompt. Single runs tell you about luck, not the model.
- Score keepers out of three, then divide cost by keepers.
- Watch full screen. Flicker and drift are invisible small.
Where they all still struggle
No current model reliably handles sustained duration, hands manipulating objects, readable on-screen text, or a specific likeness from description alone. If a comparison claims one has solved these, it was testing easy shots. See the model reference for individual strengths.
Common questions
Which AI video model is best overall?
None — the strengths diverge too much. Native audio, image-to-video fidelity and motion realism are different capabilities, so the answer depends on the shot.
How should I compare cost between models?
By cost per usable clip, not per generation. A cheaper model needing four attempts loses to a pricier one that works on the second.
Do any models generate sound?
Some generate synchronised audio natively; most output silent video. See Veo 3 for the notable native-audio option.