Scenario Reel Recast

Overview

A recast performs an existing reel again with a new performer. Seedance's edit mode takes the reel as @video1 and keeps its choreography, timing, camera and framing, while the prompt changes who dances, what they wear and how the room is dressed. The performer is rendered at the reel's scale, so anything that brings its own camera breaks the result: a background plate shot from another angle produces a performer with wrong proportions. The song never goes through generation: lift it off the reel first, lay it back on the finals.

Recast only characters the user owns or has rights to, never a real person's likeness without their consent; clearing the song for where it ships is the user's call.

Edit mode, references and moderation: scenario-seedance. Variations, review, ranking and the 1080p finish: scenario-seedance-drafts. Plate edits: scenario-image. Timeline and sync: scenario-video-assembly. Connection and the core loop: scenario. If a sibling skill named here is missing from your available skills, ask the user to install it (npx skills add scenario-labs/skills --skill <name>); unattended, proceed from tool schemas and flag the gap.

Quick reference

Step	Call	Detail
Upload	upload_asset, upload_asset_complete	Then asset_get: duration, frameRate, and the firstFrame asset id the plate starts from
Keep the song	model_scenario-audio-extract, outputFormat: "wav"	Returns inline
Mute the reference	model_scenario-video-cut, preserveAudio: false	startTime: 0 and no endTime keep the whole clip; returns inline; probe the download to confirm no audio stream remains
Room plate	Image edit of the reel's firstFrame (scenario-image)	Optional; see Changing the room, and check it before any video spend
Recast drafts	Seedance edit mode, "draft": true	referenceVideos: [muted reel], referenceImages in tag order, duration: -1, generateAudio: false; see Prompt recipe
Pick and finish	scenario-seedance-drafts	Review every take, complete only the picks
Song back	model_scenario-compose-video	A video layer and an audio layer, both at startTime: 0

The three tool ids are fixed: each is Scenario's single deterministic tool for its job, so discovery would only re-derive them. Discover the Seedance member each session per scenario-seedance.

Plan from the output, not the source: at authoring time 30 fps reels came back at 24 fps (480x854 drafts, 1080x1920 completions) and a few frames off their length either way (14.87 s gave 14.71 s, 6.00 s gave 6.04 s), and edit-mode drafts priced 366 CU for 15 s, 148 CU for 6 s.

Prompt recipe

This structure held identity, outfit and timing across three outfits and nine takes:

1. The swap: "Edit @video1: replace the dancing woman with the woman from @image1", plus "wearing the dress from @image2" and "redecorate the room as shown in @image3" when those apply. Tags follow referenceImages order: with no outfit image, the plate is @image2.
2. The keep list: "Keep from @video1 exactly: the room itself (walls, floor, window; with a plate, only its decoration changes), the camera position, height, lens and framing, her size, proportions and position in the frame, the light, and the choreography with every movement, gesture and head turn at the same timing."
3. The sheet binding: "@image1 is a character reference sheet of her: use it for her face, hair and outfit. Take nothing else from @image1: no panels, labels or text." The whole sheet works as one reference: no cropping into panels. When another image supplies the outfit, bind the sheet to face and hair only, and the outfit image to "only the dress: nothing of the mannequin, the background, the logos or any text".
4. Keeping the reel's outfit: "replace only the dancing woman's face and hair", with the outfit listed under the keep list.
5. Named fragile details: hair ("tied high at the crown, hangs down her back, keeps the same length, sections and color from the first frame to the last, never falls forward over her shoulder or blends into the curtains"), accessories ("the gloves stay black with natural fingers"), and props. Unnamed, they drifted: lace gloves vanished from one take, and a long ponytail draped forward.

Changing the room

Outcomes at authoring time, best first:

• Redecorate the reel's own room: works. Edit the firstFrame with that frame as the only reference: remove the dancer, keep walls, floor, window, camera and light, add the decoration in words, keep the center floor clear, and set the output to the frame's own pixel size so the two overlay. Then overlay the plate on the frame locally (ffmpeg -filter_complex "[0][1]blend=all_mode=average"): walls, floor line and window must coincide within a few pixels, with no sideways shift, and the original dancer must fit the empty floor at her own size. Pass the plate as the last referenceImages entry: "this same room seen from this same camera, with only the decoration changed; the decorations are fixed props that stay in place behind her and never move, morph, multiply or overlap her."
• A new location rebuilt from the frame, the same single-reference edit with the place described in words: the camera held in the overlay, but the user rejected the result. Prefer redecorating.
• A location plate from text-to-image, or a plate edit given a second scene image as a reference: fails. The plate keeps its own camera (the second reference made the editor copy that scene's angle), Seedance renders the performer at the reel's scale on top of it, and the proportions break.

Worked example: one reel, three outfits, a Halloween room

1. upload_asset the reel, upload_asset_complete, then asset_get it.
2. model_run the audio extractor and the muted cut. Download the cut and confirm it has a video stream only.
3. recommend with capability="img2img" and the decor in the user's words; edit the firstFrame as above, run the overlay check, and show the user the plate before any video spend (unattended: a passed overlay check is the gate, and a failed one stops the run before any draft).
4. Discover Seedance and model_schema_get it. dry_run one draft payload and quote N takes per outfit times that price.
5. Three payloads (the sheet outfit, an outfit image, the reel's own outfit), each sent N times with "draft": true and wait=false; jobs_wait all of them, re-called with the returned pending_job_ids until every row is done (7 to 8 minutes), never a second launch.
6. Give each draft a music review copy (step 8 recipe at the draft's length), then review per scenario-seedance-drafts, adding a timing check: the reel and the draft side by side at four matched timestamps.
7. Complete the picks with the draft job's own asset ids, never the music copies.
8. Compose each completion: the video and the extracted song as layers at startTime: 0, durationMode: "custom" at the completion's duration rounded down to the field's 0.1 s step, canvasMode: "custom" with numeric canvasWidth and canvasHeight at its size, fps at its frame rate. Then asset_download it and measure sync on that file (see Common mistakes).

Common mistakes

• Muting, extracting or muxing the song with local ffmpeg: each step has a tool model above. Local ffmpeg is for inspecting downloads.
• Writing the new performer into the plate: it then sits in the background as a second figure. The plate is the empty room.
• Spending on video before the plate passes the overlay check.
• Expecting the source's frame rate and exact length, or composing to the source's duration: take both from asset_get on the output.
• Assuming the song lands in sync at 0: the offset varies per run (one recast's dance ran 83 ms early against a track 110 ms early, another's 57 ms late against an exact track). Measure it on the final: cross-correlate its audio envelope against the reel's, and its frame-difference motion envelope against the reel's. Line the song up with the dance, not the reel's audio: the compositor moves layers in 0.1 s steps, so keep whichever of song startTime: 0.1 (dance late), song trimStart: 0.1 (dance early) or neither leaves the smaller residual.
• Promising to keep an approved performer while changing only the room: every edit re-renders the performer, so a room change means new takes. Say so before spending (unattended: run the new takes from the approved prompt and report it).