lightricks/ltx-2-19b/video-extend11 點數起 / 5 秒影片· 影片延伸LTX-2 19B 是 Lightricks 開源的音影片模型:每段影片都帶按提示詞生成的立體聲,從唱歌、對白到天氣和人群聲。文生影片、圖生影片和影片續寫,5 到 20 秒,480p、720p 或 1080p,其中 720p 很快。
在 POST /jobs/createTask 把模型名稱填成 lightricks/ltx-2-19b/video-extend 就能呼叫,11 點數/ 5 秒影片起(US$0.11)。新帳戶送 30 點數,可以先在 Playground 免費試用。
- 生成影片
- 圖生影片
- 影片延伸
- 最高 1080p
- 5–20 秒
lightricks/ltx-2-19b/video-extendPOST https://api.popnow.ai/api/v1/jobs/createTask# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
-H "Authorization: Bearer $POPNOW_API_KEY" \
-H "Content-Type: application/json" \
-H "Idempotency-Key: $IDEMPOTENCY_KEY" \
-d '{
"model": "lightricks/ltx-2-19b/video-extend",
"input": {
"prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
"video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4",
"resolution": "720p",
"duration_seconds": 5
}
}'
# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
-H "Authorization: Bearer $POPNOW_API_KEY"// Node 18+ (or any runtime with fetch). Keep the API key on your server.
const BASE = "https://api.popnow.ai/api/v1";
const headers = { Authorization: `Bearer ${process.env.POPNOW_API_KEY}` };
const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
async function call(path, init = {}) {
const res = await fetch(BASE + path, { ...init, headers: { ...headers, ...init.headers } });
const body = await res.json();
if (body.code !== 200) throw new Error(`${body.code} ${body.msg}`);
return body.data;
}
const { taskId } = await call("/jobs/createTask", {
method: "POST",
headers: { "Content-Type": "application/json", "Idempotency-Key": crypto.randomUUID() },
body: JSON.stringify({
"model": "lightricks/ltx-2-19b/video-extend",
"input": {
"prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
"video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4",
"resolution": "720p",
"duration_seconds": 5
}
}),
});
// Poll with backoff. A finished task may still be copying files: wait while an asset is pending.
let task;
for (let delay = 2000; ; delay = Math.min(delay * 1.5, 15000)) {
await sleep(delay);
task = await call(`/jobs/recordInfo?taskId=${taskId}`);
const copying = (task.output?.assets ?? []).some((a) => a.pending && !a.unavailable);
if (["succeeded", "failed", "canceled", "expired"].includes(task.state) && !copying) break;
}
if (task.state !== "succeeded") throw new Error(`${task.state}: ${task.errorMessage ?? "no detail"}`);
// Each asset has a signed url (no API key needed) that expires at expiresAt: save the file.
for (const asset of task.output.assets) console.log(asset.url);import os, time, uuid, requests
BASE = "https://api.popnow.ai/api/v1"
HEADERS = {"Authorization": f"Bearer {os.environ['POPNOW_API_KEY']}"}
def call(method, path, **kwargs):
body = requests.request(method, BASE + path, headers={**HEADERS, **kwargs.pop("headers", {})}, timeout=30, **kwargs).json()
if body["code"] != 200:
raise RuntimeError(f'{body["code"]} {body["msg"]}')
return body["data"]
task_id = call(
"POST",
"/jobs/createTask",
headers={"Idempotency-Key": str(uuid.uuid4())}, # reuse it if you retry
json={
"model": "lightricks/ltx-2-19b/video-extend",
"input": {
"prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
"video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4",
"resolution": "720p",
"duration_seconds": 5
}
},
)["taskId"]
# Poll with backoff. A finished task may still be copying files: wait while an asset is pending.
delay = 2.0
while True:
time.sleep(delay)
task = call("GET", "/jobs/recordInfo", params={"taskId": task_id})
assets = (task.get("output") or {}).get("assets") or []
copying = any(a.get("pending") and not a.get("unavailable") for a in assets)
if task["state"] in ("succeeded", "failed", "canceled", "expired") and not copying:
break
delay = min(delay * 1.5, 15.0)
if task["state"] != "succeeded":
raise RuntimeError(f'{task["state"]}: {task.get("errorMessage", "no detail")}')
# Each asset has a signed url (no API key needed) that expires at expiresAt: save the file.
for asset in assets:
print(asset["url"])input 依下方的 Schema 產生,原樣就能通過驗證。把提示詞和連結換成你自己的即可。
價格
| 選項 | 點數 /秒 | ≈ 美元 |
|---|---|---|
resolution 480p | 2.16 | US$0.022 |
resolution 720p | 2.88 | US$0.029 |
resolution 1080p | 4.32 | US$0.043 |
1 點數 = $0.01 · 全部選項及價格:GET /models/lightricks/ltx-2-19b/video-extend
每個任務會無條件進位到整數點數,所以最低檔跑一次是 11 點數/ 5 秒影片(US$0.11)。
限制
- 影片長度
- 5–20 s
- 解析度
- 480p · 720p · 1080p
- 輸入片段最長
- 60 s
參數
這些欄位來自我們驗證每個請求所用的同一份 Schema。沒列出的欄位會被拒絕。
promptstring必填Describe what happens next: the action that follows, the camera move and the sound on an Audio: line.
video_urlstring必填要處理的影片。
resolutionstring選填影響價格輸出尺寸。越大越清晰,價格也越高。
duration_secondsinteger選填影響價格影片長度,按秒計費。
seedinteger選填用同一個數字,結果就能重現。
原始 JSON Schema
{
"additionalProperties": false,
"properties": {
"duration_seconds": {
"default": 5,
"description": "Length of the new segment in whole seconds, from 5 to 20. The source clip is added on top and is not billed.",
"maximum": 20,
"minimum": 5,
"type": "integer"
},
"prompt": {
"description": "Describe what happens next: the action that follows, the camera move and the sound on an Audio: line.",
"minLength": 1,
"type": "string"
},
"resolution": {
"default": "720p",
"description": "Resolution of the new segment. It sets how sharp the new part is generated; match your source clip.",
"enum": [
"480p",
"720p",
"1080p"
],
"type": "string"
},
"seed": {
"description": "Random seed for controlled comparisons, not a frame-identical guarantee.",
"maximum": 2147483647,
"minimum": 0,
"type": "integer"
},
"video_url": {
"contentMediaType": [
"video/mp4",
"video/webm",
"video/quicktime"
],
"description": "The clip to continue: MP4, MOV or WebM, up to 60 seconds. Its last frame opens the new segment, and the result is your clip with the new segment joined on.",
"format": "uri",
"minLength": 1,
"type": "string"
}
},
"required": [
"prompt",
"video_url"
],
"type": "object"
}回應、輪詢與回呼
所有模型的用法都一樣:先建立任務,再輪詢,或等待回呼。
先報價
curl -X POST https://api.popnow.ai/api/v1/jobs/quote \
-H "Authorization: Bearer $POPNOW_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "lightricks/ltx-2-19b/video-extend",
"input": {
"prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
"video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4",
"resolution": "720p",
"duration_seconds": 5
}
}'請求內容和 createTask 相同。它回傳預估扣款和最高可能扣款,不會真的執行。
已受理
HTTP/1.1 202 Accepted
{
"code": 200,
"msg": "success",
"data": {
"taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
"state": "queued"
},
"request_id": "req_example_create"
}HTTP 202 代表任務已受理,點數先凍結、尚未扣除。最終扣款不會超過凍結額。
查詢狀態
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
-H "Authorization: Bearer $POPNOW_API_KEY"每隔幾秒查詢一次並逐步拉長間隔,state 變成 succeeded、failed、canceled 或 expired 時停止。
完成的任務
{
"code": 200,
"msg": "success",
"data": {
"taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
"model": "lightricks/ltx-2-19b/video-extend",
"state": "succeeded",
"output": {
"assets": [
{
"url": "https://cdn.popnow.ai/tasks/task_01k3m8x9q2z4v7n5p6r8s0t1w3/output.mp4?signature=FROM_RESPONSE",
"expiresAt": "2026-10-17T12:20:00Z",
"mime": "video/mp4",
"width": 1280,
"height": 720,
"durationSeconds": 5
}
]
},
"settled": true
},
"request_id": "req_example_record"
}請在 expiresAt 之前從 url 下載。之後需要新連結,請呼叫 POST /common/download-url。
驗證回呼
import { createHash, createHmac, timingSafeEqual } from "node:crypto";
import express from "express";
const app = express();
// express.raw keeps the exact bytes that were signed; express.json would not match.
app.post("/hooks/popnow", express.raw({ type: "application/json" }), (req, res) => {
const timestamp = req.header("X-Webhook-Timestamp");
const signature = req.header("X-Webhook-Signature") ?? "";
const body = JSON.parse(req.body.toString("utf8"));
const taskId = body.data?.taskId ?? body.task_id;
const digest = createHash("sha256").update(req.body).digest("hex");
const expected = createHmac("sha256", process.env.POPNOW_WEBHOOK_SECRET)
.update(`${taskId}.${timestamp}.${digest}`)
.digest("base64");
const ok = expected.length === signature.length && timingSafeEqual(Buffer.from(expected), Buffer.from(signature));
// Check the signature first, then reject anything older than five minutes.
if (!ok || Math.abs(Date.now() / 1000 - Number(timestamp)) > 300) return res.status(401).end();
res.status(200).end(); // answer fast, then fetch the task and store its files
});設定 callBackUrl 後,我們會把完成的任務送給你。先用原始請求內容驗證簽名,再信任它。
上傳本機檔案
curl -X POST https://api.popnow.ai/api/v1/common/upload-url \
-H "Authorization: Bearer $POPNOW_API_KEY" \
-H "Content-Type: application/json" \
-d '{"contentType": "image/png", "bytes": 482113}'
# PUT the file bytes to data.uploadUrl with every header in data.headers, then commit it:
curl -X POST https://api.popnow.ai/api/v1/files/$FILE_ID/commit \
-H "Authorization: Bearer $POPNOW_API_KEY"
# The commit returns a popnow://f/... reference. Put it in any image, video or
# audio field of the task input instead of a public https URL.公開的 https 連結可以直接用。本機檔案要先經過 upload-url 和 commit。

