Seedance 1.5 Pro API

Seedance 1.5 Pro Video extend continues a clip you already have. Send it as video_url and a prompt for what happens next. The final frame of your clip becomes the opening frame of a new Seedance 1.5 Pro image-to-video shot of 4 to 12 seconds, and the two are joined into one MP4: your original first, then the continuation, with the repeated seam frame removed. The new segment also comes back as its own file, so you can keep extending or edit the pieces separately.

Continuity comes from the last frame. Wardrobe, set, light and where everyone stands carry over because the new segment literally starts on your final frame. Motion does not carry over the same way: the model sees one still, not the whole clip, so describe the movement you want to continue instead of assuming it will keep its speed or direction.

One file back, plus the new piece on its own. The joined file keeps your clip’s frame rate and its framing, with no black bars, and is encoded as H.264 MP4 with AAC sound. To line the seam up, the picture may be trimmed or adjusted by a few percent at the edges. If the model returns a noticeably different shape, the new segment is scaled to fill your frame and centered, cropping what spills over. Sound from your source stays, sound generated for the new segment follows it with a short crossfade at the seam, and a silent side is padded with silence. The second asset in the output is the new segment alone, ready for another extend or for an editor.

An optional end frame. Add last_image_url and the new segment lands on that picture (480p and 720p), which makes a transition or a return to a known frame repeatable.

Everything else is Seedance 1.5 Pro image-to-video. The new segment runs on the same routes, with the same content range and the same per-second price as the image-to-video endpoint, and a failed generation is refunded the same way. If the generation succeeds but the join itself cannot be built, the task fails and the charge is refunded in full.

Lengthen a shot that ended too early: a product turntable that stops before the label faces camera, or a walk that cuts before the subject reaches the door. Extend it by a few seconds and describe only the remaining motion.

Build a longer sequence step by step. Generate a first shot, extend it, then extend the joined result again; each step bills only the seconds it adds, and the source of each step can be up to 60 seconds. Because every step starts from a single frame, watch each seam before stacking the next one.

# Generate the idempotency key once; reuse it when retrying after a lost response.
export SPICY_IDEMPOTENCY_KEY="${SPICY_IDEMPOTENCY_KEY:-$(uuidgen)}"
curl -X POST https://api.spicyapi.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $SPICY_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $SPICY_IDEMPOTENCY_KEY" \
  -d '{
  "model": "bytedance/seedance-1.5-pro/video-extend",
  "input": {
    "duration_seconds": 5,
    "generate_audio": true,
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "resolution": "720p",
    "video_url": "https://example.com/reference.mp4"
  }
}'

# Copy data.taskId from the response into TASK_ID, then poll the status.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.spicyapi.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $SPICY_API_KEY"

See the API reference for authentication, the complete schema, polling, and error handling.