Choose a workflow that edits existing footage when the original scene is essential. Animating a new character photograph is a different starting point: that photograph may establish a new background and framing. Before uploading, decide whether you are replacing appearance, changing a performance, or rebuilding the shot. Those tasks can require different inputs.
Make a five-part inheritance list
Divide the desired result into character appearance, body action, facial performance, camera movement and environment. Mark each item “keep from source,” “replace,” or “may vary.”
For a dancer in a courtyard, you might keep the dance, camera pullback and courtyard while replacing only the dancer. For a speaking character, you might keep an existing animated scene and replace the facial performance. These are distinct briefs even if both begin with a video and an image.
Avoid a vague instruction to preserve “everything else.” List the visible evidence: the doorway stays behind the same shoulder, the floor contact remains readable and the camera ends with the same surrounding space.
Check what the selected mode actually transfers
Act-Two's official guide says character-video inputs retain scene and camera motion, while gesture control is unavailable. This is performance animation of the supplied character video, not proof of appearance replacement.
Runway lists Character Swap separately. The name identifies a dedicated workflow; it does not establish that every actor, occlusion and background detail survives unchanged.
| Starting asset | Your intended change | Question for the tool |
|---|---|---|
| Original live-action video | Replace actor appearance | Does this mode edit the existing clip? |
| New character still | Add recorded body motion | Which input defines the setting? |
| Existing character video | Change facial performance | Which movements remain from that video? |
| Several actors in one scene | Replace selected identities | How are targets assigned individually? |
Build a source comparison that survives rewatching
Save the original clip and three frame grabs from the beginning, the most difficult interaction and the ending. Choose landmarks outside the character: a wall corner, a window edge and a floor line work better than moving reflections.
Review those landmarks alongside the person's feet or seat contact. If the environment looks unchanged but the character floats above the floor, scene preservation alone has not made the replacement usable. If a doorway changes during an arm movement, note the first frame where it changes rather than judging only attractive endpoints.
Keep a separate list for facial identity. A close likeness cannot compensate for a missing action or an altered background needed by the story.
Isolate one replacement before expanding
Begin with one visible subject and one continuous event. When the clip contains crossing people, write down which person owns each action and which identities must remain. Do not expect an unlabelled group photograph to perform that assignment for you.
Preserve the source duration during the first comparison. Trimming, slowing and replacing the character simultaneously makes a mismatched ending difficult to diagnose. Once the replacement is acceptable, perform the delivery edit separately.
Two practical follow-ups
Will a new background in my character image appear in the result?
It may influence a workflow that uses the image as scene evidence. Check the selected mode's input instructions and remove this ambiguity before testing.
Should I use an image instead if the original scene is imperfect?
Use an image when rebuilding the scene is acceptable. If the location or camera move documents something specific, keep the original footage as your comparison and assess an actual video-editing workflow.