# Seedance 2.0 Fast Text to Video

> Generate a short video with synchronized audio straight from a text prompt — the faster, lower-cost Seedance 2.0 tier, at up to 720p.

## Overview

- **Endpoint**: `https://queue.modelrunner.run/bytedance/seedance-v2-fast/text-to-video`
- **Model ID**: `bytedance/seedance-v2-fast/text-to-video`
- **Category**: text-to-video
- **Kind**: inference
- **Tags**: video, text-to-video, video generation, audio, fast, bytedance, seedance

## Pricing

- **Price**: $0.181 per output second

## Request Lifecycle

This model runs on the ModelRunner **asynchronous queue API** — a single POST does not return the output. Every call requires an `Authorization: Key $MODEL_RUNNER_KEY` header. Run three steps:

1. **Submit** — `POST https://queue.modelrunner.run/bytedance/seedance-v2-fast/text-to-video` with a JSON body holding the input fields at the top level. The body may also include a reserved top-level `metadata` object — a flat string map (max 16 keys, key ≤64 / value ≤512 chars) stored on the request for your own tagging. It is never sent to the model; filter your request history with `GET https://queue.modelrunner.run/requests?metadata=<url-encoded JSON>` (exact key=value matches, AND-ed). The response carries request handles only (no output yet):

```json
{
  "status": "IN_QUEUE",
  "request_id": "<21-char id>",
  "status_url": "https://queue.modelrunner.run/bytedance/seedance-v2-fast/text-to-video/requests/<request_id>/status",
  "response_url": "https://queue.modelrunner.run/bytedance/seedance-v2-fast/text-to-video/requests/<request_id>",
  "cancel_url": "https://queue.modelrunner.run/bytedance/seedance-v2-fast/text-to-video/requests/<request_id>/cancel"
}
```

2. **Poll status** — `GET <status_url>` until `status` is `COMPLETED`. Possible values are `IN_QUEUE`, `IN_PROGRESS`, `COMPLETED`, `FAILED`, `CANCELLED`. A `FAILED` request responds with HTTP 400 and an `error` field.

3. **Read result** — `GET <response_url>`. Returns the finished request, including the generated `output`:

```json
{ "id": "<request_id>", "status": "COMPLETED", "output": ..., "input": ... }
```

The JavaScript and Python SDKs below perform steps 2–3 for you. In any language without an SDK (Swift, Go, Kotlin, etc.) you must implement the polling loop and the final result fetch yourself — see the cURL example for the full flow.

### Input Schema

- **`prompt`** (`string`, _required_):
  Describe the scene, the action, the camera move, and the sound you want. English, Chinese, Japanese, Indonesian, Spanish and Portuguese prompts are all understood.

- **`duration`** (`integer`, _optional_):
  Clip length in seconds.
  - Default: `5`
  - Range: `4` to `15`

- **`resolution`** (`resolution`, _optional_):
  Output resolution of the clip. This tier tops out at 720p; the higher resolution costs more per second of video.
  - Default: `"720p"`
  - Options: `"480p"`, `"720p"`

- **`aspect_ratio`** (`aspect_ratio`, _optional_):
  Frame shape of the clip. Use adaptive to let the model pick the framing.
  - Default: `"16:9"`
  - Options: `"16:9"`, `"4:3"`, `"1:1"`, `"3:4"`, `"9:16"`, `"21:9"`, `"adaptive"`

- **`generate_audio`** (`boolean`, _optional_):
  Generate a synchronized soundtrack (dialogue, ambience and sound effects) together with the picture. Set false for a silent clip; the price is the same either way.
  - Default: `true`

### Output Schema

_No `Output` schema properties are available._

## Default Example

**Input**

```json
{
  "prompt": "A glassblower turns a glowing gob of molten glass at the furnace mouth, orange light flaring across their leather apron as the blowpipe rotates, the dim workshop falling away behind",
  "duration": 5,
  "resolution": "720p",
  "aspect_ratio": "16:9",
  "generate_audio": true
}
```

**Output**

```json
"https://media.modelrunner.ai/cdBzrh3j7BA1zdZfsKVyw.mp4"
```
## Usage Examples

### cURL

The queue API is asynchronous: submit the request, poll `status_url` until it is `COMPLETED`, then read the result from `response_url`. Requires `jq`.

```bash
# 1. Submit the request (returns request handles, not the output)
SUBMIT=$(curl --silent --request POST \
  --url https://queue.modelrunner.run/bytedance/seedance-v2-fast/text-to-video \
  --header "Authorization: Key $MODEL_RUNNER_KEY" \
  --header "Content-Type: application/json" \
  --data '{
  "prompt": "A glassblower turns a glowing gob of molten glass at the furnace mouth, orange light flaring across their leather apron as the blowpipe rotates, the dim workshop falling away behind",
  "duration": 5,
  "resolution": "720p",
  "aspect_ratio": "16:9",
  "generate_audio": true
}')

STATUS_URL=$(echo "$SUBMIT" | jq -r '.status_url')
RESPONSE_URL=$(echo "$SUBMIT" | jq -r '.response_url')

# 2. Poll until the request leaves the queue / in-progress state
while true; do
  STATUS=$(curl --silent --url "$STATUS_URL" \
    --header "Authorization: Key $MODEL_RUNNER_KEY" | jq -r '.status')
  echo "Status: $STATUS"
  case "$STATUS" in
    COMPLETED) break ;;
    FAILED|CANCELLED) echo "Request $STATUS"; exit 1 ;;
  esac
  sleep 1
done

# 3. Read the finished request, including the generated output
curl --silent --url "$RESPONSE_URL" \
  --header "Authorization: Key $MODEL_RUNNER_KEY"
```

### JavaScript

```javascript
import { modelrunner } from "@modelrunner/client";

const result = await modelrunner.subscribe("bytedance/seedance-v2-fast/text-to-video", {
  input: {
  "prompt": "A glassblower turns a glowing gob of molten glass at the furnace mouth, orange light flaring across their leather apron as the blowpipe rotates, the dim workshop falling away behind",
  "duration": 5,
  "resolution": "720p",
  "aspect_ratio": "16:9",
  "generate_audio": true
}
});

console.log(result.data);
```

### Python

```python
import asyncio
import modelrunner_ai

async def main():
    response = await modelrunner_ai.submit_async(
        "bytedance/seedance-v2-fast/text-to-video",
        arguments={
  "prompt": "A glassblower turns a glowing gob of molten glass at the furnace mouth, orange light flaring across their leather apron as the blowpipe rotates, the dim workshop falling away behind",
  "duration": 5,
  "resolution": "720p",
  "aspect_ratio": "16:9",
  "generate_audio": true
}
    )
    result = await response.get()
    print(result["output"])

asyncio.run(main())
```

## Additional Resources

- [Playground](https://modelrunner.ai/models/bytedance/seedance-v2-fast/text-to-video)
- [OpenAPI Schema](https://modelrunner.ai/models/bytedance/seedance-v2-fast/text-to-video/openapi.json)
- [LLM Instructions](https://modelrunner.ai/models/bytedance/seedance-v2-fast/text-to-video/llms.txt)