Seedance 2.5 video editing requires duration=-1 and aspect_ratio=adaptive, but OpenRouter API does not support these values

[jjeejj]

Seedance 2.5 video editing requires duration=-1 and aspect_ratio=adaptive, but OpenRouter API does not support these values

Problem

Seedance 2.5 video editing appears to require special parameter values that are not currently supported by OpenRouter's normalized Video API.

For a video editing request using input_references with a video reference, Seedance identifies the request as a video editing task and returns the following error:

The parameter duration specified in the request is not valid. Seedance identified your task as video editing based on your prompt. For this task type, the output ratio and duration follow the input video selected by the model for editing, and the video selected must satisfy the duration requirement of 4 to 30 seconds. Issues: [0] duration must be -1.

According to the Seedance 2.5 video editing behavior, the required parameters appear to be:

duration = -1
aspect_ratio = adaptive

However, the OpenRouter Video Models API currently reports the following capabilities for bytedance/seedance-2.5:

{
  "supported_durations": [4, 5, 6, ..., 30],
  "supported_aspect_ratios": [
    "16:9",
    "4:3",
    "1:1",
    "3:4",
    "9:16",
    "21:9"
  ],
  "allowed_passthrough_parameters": [
    "watermark",
    "req_key",
    "output_format"
  ]
}

Neither -1 nor adaptive is exposed as a supported value.

I also tried passing duration: -1 directly to the /api/v1/videos endpoint, but the request still fails.

I also tried passing the value through provider-specific options, but duration is not listed as an allowed passthrough parameter.

Example Request

{
  "model": "bytedance/seedance-2.5",
  "prompt": "Replace the driver in the video with a middle-aged man wearing a red short-sleeved shirt. Modify the voice accordingly. Keep everything else exactly the same.",
  "duration": -1,
  "input_references": [
    {
      "type": "video_url",
      "video_url": {
        "url": "https://example.com/input.mp4"
      }
    }
  ]
}

Expected Behavior

For a Seedance 2.5 video editing request, OpenRouter should either:

1. Support the required duration=-1 and aspect_ratio=adaptive values for this editing mode, or
2. Automatically translate the normalized OpenRouter parameters into the provider-specific parameters required by Seedance 2.5.

Questions

Could you please confirm:

1. Is Seedance 2.5 video editing with video input_references currently fully supported through /api/v1/videos?
2. If yes, how should duration=-1 and aspect_ratio=adaptive be specified through OpenRouter?
3. If these values are intentionally not supported by the normalized API, is there another way to invoke the Seedance 2.5 video editing mode through OpenRouter?
4. Is this a known limitation or bug in the current Seedance 2.5 integration?

Thank you.

[gaetanvdb-arinti]

Same issue here, with a few extra findings that may help:

1. Omitting duration does not work either: OpenRouter seems to inject a default duration, so Seedance 2.5 still fails with "duration must be -1"
2. Passing duration: -1 via provider.options.seed.parameters is silently dropped (same error).

So true "match the input video" editing is currently impossible for Seedance 2.5 via /api/v1/videos. Allowing duration: -1 (and aspect_ratio: "adaptive") for Seedance models, or passing them through for edit tasks, would fix it.