视频生成（原生接口）

curl -X POST "$BASE_URL/v1beta/models/veo-3.1-generate-preview:predictLongRunning" \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "instances": [{
      "prompt": "a drone rises from a beach at sunset, cinematic"
    }],
    "parameters": {
      "durationSeconds": 6,
      "aspectRatio": "16:9",
      "resolution": "720p"
    }
  }'

{
  "name": "operations/abc123xyz",
  "done": false
}

{
  "instances": [{
    "prompt": "night city with neon rain",
    "image": {"uri": "https://example.com/ref.jpg"}
  }],
  "parameters": {
    "durationSeconds": 6,
    "aspectRatio": "16:9"
  }
}

{
  "instances": [{
    "prompt": "transition effect",
    "image": {"uri": "https://example.com/first.jpg"}
  }],
  "parameters": {
    "durationSeconds": 6,
    "lastFrame": {"uri": "https://example.com/last.jpg"}
  }
}

curl "$BASE_URL/v1beta/operations/{operation_id}" \
  -H "Authorization: Bearer $TOKEN"

{
  "name": "operations/abc123xyz",
  "done": true,
  "response": {
    "generateVideoResponse": {
      "generatedSamples": [{
        "video": {"uri": "https://.../video.mp4"}
      }]
    }
  }
}