Seedance 2.0 Fast

ByteDance’s Seedance 2.0 Fast video generation model with multimodal reference, video editing, extension, audio generation, and web search.

Seedance 2.0 Fast is ByteDance’s latest video generation model available through AnyFast API. It supports text-to-video, image-to-video, multimodal reference input, video editing, video extension, and synchronized audio generation.

Key capabilities

Feature	Description
Text-to-video	Generate video from text prompts
Image-to-video (first frame)	Use an image as the first frame
Image-to-video (first + last frame)	Use two images as first and last frames
Multimodal reference	Combine images, videos, and audio as references (0–9 images, up to 3 videos, up to 3 audio clips)
Video editing	Modify elements in an existing video using reference images
Video extension	Extend and concatenate reference videos
Audio generation	Auto-generate synchronized voice, sound effects, and background music
Web search	Enhance generation with real-time internet content (text-to-video only)
Return last frame	Retrieve the last frame of generated video

Output specifications

Property	Value
Resolution	480p, 720p
Aspect ratio	16:9, 4:3, 1:1, 3:4, 9:16, 21:9, adaptive
Duration	4–15 seconds
Format	mp4
Frame rate	24 fps

Workflow

1. POST /v1/video/generations  →  task_id
2. Poll GET /v1/video/generations/{task_id}  →  status
3. When status = "succeeded"  →  download video URL (valid 24 hours)

Examples

Text-to-video

cURL

curl https://www.anyfast.ai/v1/video/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-fast",
    "content": [
      {
        "type": "text",
        "text": "A cat playing piano in a sunlit room, cinematic lighting"
      }
    ],
    "generate_audio": true,
    "ratio": "16:9",
    "duration": 8
  }'

import requests
import time

headers = {"Authorization": "Bearer YOUR_API_KEY", "Content-Type": "application/json"}

# Step 1: create task
resp = requests.post(
    "https://www.anyfast.ai/v1/video/generations",
    headers=headers,
    json={
        "model": "seedance-fast",
        "content": [
            {"type": "text", "text": "A cat playing piano in a sunlit room, cinematic lighting"}
        ],
        "generate_audio": True,
        "ratio": "16:9",
        "duration": 8
    }
)
task_id = resp.json()["task_id"]

# Step 2: poll for result
while True:
    result = requests.get(
        f"https://www.anyfast.ai/v1/video/generations/{task_id}",
        headers=headers
    ).json()
    status = result["data"]["status"]
    if status == "SUCCESS":
        print("Video URL:", result["data"]["data"]["content"]["video_url"])
        break
    elif status == "FAILED":
        print("Failed:", result["data"].get("fail_reason"))
        break
    time.sleep(5)

Multimodal reference (image + video + audio)

Reference assets in the prompt with @image1, @video1, @audio1 — numbered per media type by their order in the content array.

Important: Assets must be passed in strict order: text, image_url, video_url, audio_url. Do not reorder them — doing so may cause errors. When multiple assets are included, do not mix in other asset types.

cURL

curl https://www.anyfast.ai/v1/video/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-fast",
    "content": [
      {
        "type": "text",
        "text": "The character from @image1 dances in the scene from @video1, with @audio1 as background music"
      },
      {
        "type": "image_url",
        "image_url": {"url": "https://example.com/character.jpg"},
        "role": "reference_image"
      },
      {
        "type": "video_url",
        "video_url": {"url": "https://example.com/clip.mp4"},
        "role": "reference_video"
      },
      {
        "type": "audio_url",
        "audio_url": {"url": "https://example.com/bgm.mp3"},
        "role": "reference_audio"
      }
    ],
    "generate_audio": true,
    "ratio": "16:9",
    "duration": 11
  }'

Video editing

cURL

curl https://www.anyfast.ai/v1/video/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-fast",
    "content": [
      {
        "type": "text",
        "text": "Replace the water bottle in @video1 with the perfume bottle from @image1, keep camera movement unchanged"
      },
      {
        "type": "image_url",
        "image_url": {"url": "https://example.com/perfume.jpg"},
        "role": "reference_image"
      },
      {
        "type": "video_url",
        "video_url": {"url": "https://example.com/original.mp4"},
        "role": "reference_video"
      }
    ],
    "generate_audio": true,
    "ratio": "16:9",
    "duration": 5
  }'

Web search enhanced (text-to-video only)

cURL

curl https://www.anyfast.ai/v1/video/generations \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-fast",
    "content": [
      {
        "type": "text",
        "text": "Macro shot of cherry blossoms in spring, petals falling slowly"
      }
    ],
    "generate_audio": true,
    "ratio": "16:9",
    "duration": 11,
    "tools": [{"type": "web_search"}]
  }'

Parameters

Parameter	Type	Required	Description
model	string	Yes	seedance-fast
content	array	Yes	Input content array (text, image_url, video_url, audio_url items)
content[].type	string	Yes	text, image_url, video_url, or audio_url
content[].text	string	Text items	Text prompt (max 500 Chinese chars / 1000 English words)
content[].image_url.url	string	Image items	Image URL, Base64 data URI, or asset://<ID>
content[].video_url.url	string	Video items	Video URL or asset://<ID> (mp4/mov, max 50 MB, 2–15s)
content[].audio_url.url	string	Audio items	Audio URL, Base64 data URI, or asset://<ID> (wav/mp3, max 15 MB)
content[].role	string	Conditional	first_frame, last_frame, reference_image, reference_video, reference_audio
generate_audio	boolean	No	Generate synchronized audio. Default: true
resolution	string	No	480p or 720p. Default: 720p. Seedance 2.0 Fast does not support 1080p.
ratio	string	No	16:9, 4:3, 1:1, 3:4, 9:16, 21:9, adaptive. Default: adaptive
duration	integer	No	4–15 seconds. Default: 5
tools	array	No	[{"type": "web_search"}] for web search (text-to-video only)
watermark	boolean	No	Add watermark. Default: false

Input modes

Mode	Content items	role values
Text-to-video	1× text	—
Image-to-video (first frame)	text (optional) + 1× image_url	first_frame or omit
Image-to-video (first + last frame)	text (optional) + 2× image_url	first_frame + last_frame
Multimodal reference	text (optional) + image/video/audio	reference_image, reference_video, reference_audio
Video editing	text + image_url + video_url	reference_image + reference_video
Video extension	text + video_url(s)	reference_video

Note: First frame, first+last frame, and multimodal reference are mutually exclusive — do not mix them in the same request.

Referencing assets in prompts

Inside the text prompt, you can refer to media items using @<type><N> placeholders — numbered per media type by their order in the content array:

Placeholder	Refers to
@image1, @image2, …	The 1st, 2nd, … image_url item
@video1, @video2, …	The 1st, 2nd, … video_url item
@audio1, @audio2, …	The 1st, 2nd, … audio_url item

Example: "The character from @image1 walks through the scene in @video1 with @audio1 as background".

Note: Assets must be passed in strict order: text, image_url, video_url, audio_url. Do not reorder them — doing so may cause errors. When multiple assets are included, do not mix in other asset types.

Resolution pixel values

Resolution	16:9	4:3	1:1	3:4	9:16	21:9
480p	864x496	752x560	640x640	560x752	496x864	992x432
720p	1280x720	1112x834	960x960	834x1112	720x1280	1470x630

API Reference

View the interactive API playground for Seedance 2.0 Fast.