Video
Keyframe
A keyframe is a frame whose content is fixed rather than generated, and which the motion is built around. In AI video the start frame and, where supported, the end frame are the keyframes.
Fixing a frame converts an open-ended generation into a constrained one. The engine no longer invents the subject, only the journey — which is why a keyframed clip is far more predictable than a text-only one.
Two keyframes turn the clip into a transition between two images you already approve, which is the most reliable way to make a generated shot land exactly where the edit needs it.
On eroq
Every engine accepts a start frame — a photo or a render from the image studio, and on Motion One a saved Character's picture too. eroq Motion One, Seedance, Veo, Kling and Hailuo also accept an end frame and interpolate between the two; on those engines an end frame can also ride on its own.
Questions
Which engines take two keyframes?
eroq Motion One, Seedance, Veo, Kling and Hailuo. Motion Pro, Runway Gen-4.5, Grok Imagine and Wan 3.0 take a start frame only.
Can I give only an end frame?
Yes, on the engines that take an end frame — it is sent on its own and the clip is rendered to land on it. Giving both is the tighter setup, because the engine then interpolates between two images you already approve.
Does a keyframe guarantee the subject stays the same?
It anchors it strongly but does not freeze it — the further the clip travels from the keyframe, the more drift you get, which is one reason shorter clips hold together better.