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LTX 2.3 Plus API

Lightricks 出品

LTX 2.3 图生视频,3 到 20 秒,最高 1080p

lightricks/ltx-2.3-plus/video-extend
  • 最高 1080p
  • 3–20 秒
  • 图生视频
  • 视频续写

在 POST /jobs/createTask 里把模型名写成 lightricks/ltx-2.3-plus/video-extend 即可调用,US$0.095 起。

调用名lightricks/ltx-2.3-plus/video-extend
接口POST 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-2.3-plus/video-extend",
  "input": {
    "preset": "tuned",
    "duration_seconds": 5,
    "resolution": "480p",
    "video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4"
  }
}'

# 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"

input 按下面的 Schema 生成,原样就能通过校验。把提示词和链接换成你自己的即可。

价格

选项USD /秒
resolution 480pUS$0.019
resolution 720pUS$0.038
resolution 1080pUS$0.057

美元计费 · 全部选项及价格:GET /models/lightricks/ltx-2.3-plus/video-extend

限制

视频时长
3–20 s
分辨率
480p · 720p · 1080p
输入片段最长
60 s

参数

这些字段来自我们校验每个请求所用的同一份 Schema。没列出的字段会被拒绝。

  • video_urlstring必填

    要处理的视频。

    范围
    1 – … chars · video/mp4, video/webm, video/quicktime, video/x-m4v
  • presetstring可选

    Style preset bundle. tuned is the recommended general-purpose stack; original applies light styling only.

    默认值
    "tuned"
    可选值
    "tuned""original"
  • promptstring可选

    Describe what happens next: the action that follows and the camera move. You can leave it empty.

  • duration_secondsinteger可选影响价格

    视频时长,按秒计费。

    默认值
    5
    范围
    3 – 20
  • resolutionstring可选影响价格

    输出尺寸。越大越清晰,价格也越高。

    默认值
    "480p"
    可选值
    "480p""720p""1080p"
  • seedinteger可选

    用同一个数字,结果就能复现。

    范围
    0 – 2147483647
原始 JSON Schema
{
  "additionalProperties": false,
  "properties": {
    "duration_seconds": {
      "default": 5,
      "description": "Length of the new segment in whole seconds, from 3 to 20. The source clip is added on top and is not billed.",
      "maximum": 20,
      "minimum": 3,
      "type": "integer"
    },
    "preset": {
      "default": "tuned",
      "description": "Style preset bundle. tuned is the recommended general-purpose stack; original applies light styling only.",
      "enum": [
        "tuned",
        "original"
      ],
      "type": "string"
    },
    "prompt": {
      "description": "Describe what happens next: the action that follows and the camera move. You can leave it empty.",
      "type": "string"
    },
    "resolution": {
      "default": "480p",
      "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. Keep it fixed only for controlled comparisons, not as a frame-identical guarantee.",
      "maximum": 2147483647,
      "minimum": 0,
      "type": "integer"
    },
    "video_url": {
      "contentMediaType": [
        "video/mp4",
        "video/webm",
        "video/quicktime",
        "video/x-m4v"
      ],
      "format": "uri",
      "minLength": 1,
      "type": "string"
    }
  },
  "required": [
    "video_url"
  ],
  "type": "object"
}

响应、轮询与回调

所有模型的用法都一样:先建任务,再轮询,或者等回调。

先报价

cURL
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-2.3-plus/video-extend",
  "input": {
    "preset": "tuned",
    "duration_seconds": 5,
    "resolution": "480p",
    "video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4"
  }
}'

运行前,将相同请求体发送到 POST /jobs/quote,可查看预计费用和最高费用,单位为美元。报价不会运行任务或扣款。

已受理

HTTP
HTTP/1.1 202 Accepted

{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "state": "queued"
  },
  "request_id": "req_example_create"
}

HTTP 202 表示已受理:最高美元金额已冻结,等待结算。 任务受理时,从 API 余额中冻结报价的最高金额;完成后按实际用量结算,实扣不超过冻结额,并释放剩余金额。任务失败则释放冻结额。

查询状态

cURL
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

每隔几秒查一次并逐步拉长间隔,state 变成 succeeded、failed、canceled 或 expired 时停止。

完成的任务

JSON
{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "task_01k3m8x9q2z4v7n5p6r8s0t1w3",
    "model": "lightricks/ltx-2.3-plus/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"
}

在 expiresAt 之前从 url 下载。之后要新链接,请调用 POST /common/download-url。

校验回调

Node.js
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
});

设置了 callBackUrl,我们会把完成的任务发给你。先用原始请求体校验签名,再信任它。

上传本地文件

cURL
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.

公开的 https 链接可以直接用。本地文件要先经过 upload-url 和 commit。

关于 LTX 2.3 Plus

LTX 2.3 图生视频,3 到 20 秒,最高 1080p。

在 POST /jobs/createTask 里把模型名写成 lightricks/ltx-2.3-plus/video-extend 即可调用,US$0.095 起。

请求参数

参数必填说明
duration_seconds否视频时长,按秒计费。 ≥ 3 · ≤ 20 · 默认值: 5
preset否Style preset bundle. tuned is the recommended general-purpose stack; original applies light styling only. tuned · original · 默认值: tuned
prompt否Describe what happens next: the action that follows and the camera move. You can leave it empty.
resolution否输出尺寸。越大越清晰,价格也越高。 480p · 720p · 1080p · 默认值: 480p
seed否用同一个数字,结果就能复现。 ≥ 0 · ≤ 2147483647
video_url是要处理的视频。

价格

价格以美元计。API 使用独立的美元余额。网站积分不能用于 API,也不能转入 API 余额;API 余额同样不能转为网站积分。 任务受理时,从 API 余额中冻结报价的最高金额;完成后按实际用量结算,实扣不超过冻结额,并释放剩余金额。任务失败则释放冻结额。

选项USD /秒
resolution 480pUS$0.019
resolution 720pUS$0.038
resolution 1080pUS$0.057

运行前,将相同请求体发送到 POST /jobs/quote,可查看预计费用和最高费用,单位为美元。报价不会运行任务或扣款。

API 快速上手

三步调用 LTX 2.3 Plus API

  1. 创建 API 密钥. 登录 PopNow,在 API 控制台创建密钥。密钥以 sk-popnow- 开头,API 调用使用独立的美元余额。
  2. 发送请求. 向 POST /jobs/createTask 发请求,model 填 lightricks/ltx-2.3-plus/video-extend,input 按参数表填写。响应会立刻返回任务 ID。
  3. 取回结果. 用任务 ID 轮询 GET /jobs/recordInfo,或者传 callBackUrl,结果会推送到这个地址。任务成功后下载输出链接。
# 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-2.3-plus/video-extend",
  "input": {
    "preset": "tuned",
    "duration_seconds": 5,
    "resolution": "480p",
    "video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4"
  }
}'

# 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"

请把提示词和链接换成你自己的。API 页签里有响应、轮询和回调的参考。

LTX 2.3 Plus API 常见问题

LTX 2.3 Plus API 怎么收费?

LTX 2.3 Plus:最便宜的任务是视频续写,US$0.095/ 5 秒视频起。各选项价格:480p US$0.019/秒、720p US$0.038/秒、1080p US$0.057/秒。API 使用独立的美元余额。网站积分不能用于 API,也不能转入 API 余额;API 余额同样不能转为网站积分。 任务受理时,从 API 余额中冻结报价的最高金额;完成后按实际用量结算,实扣不超过冻结额,并释放剩余金额。任务失败则释放冻结额。

LTX 2.3 Plus · 视频续写 API 有哪些限制?

视频时长:3–20 s;分辨率:480p · 720p · 1080p;输入片段最长:60 s。超出这些限制的请求会在扣费之前被拒绝。

关于 LTX 2.3 Plus 的更多内容