roasOS
ModelsAssembly

FFmpeg Trim Video

Trim Video cuts one window out of a finished clip: state where the cut starts and where it ends, and the result is a new, shorter clip.

Family assembly · model trim-video · catalog model-catalog@2026-10-06.v5 · pricing customer-pricing@2026-11-05.v15.

Endpoint

POST https://api.roasos.com/v1/assembly/trim-video

Send your API key as a bearer token. The key needs the scope api:write. Every paid request also needs an Idempotency-Key header.

The envelope fields quote_only, quote_id, webhook_url and wait_timeout_seconds behave the same on each model endpoint. Refer to Jobs and Quotes and credits.

Good at

Cut a long source down before an operation with a length ceiling — a recast source must be 15 seconds or shorter, and this door is the trim primitive that gets it there. Also good for pulling one usable segment out of a long take.

The price is one credit, flat.

Pricing

The unit is one operation. Pricing key: trim-video.

RequestCredits
per_operation1

The credits come from the roasOS pricing table. No other field changes the price. To get the exact price of your request, send it with quote_only: true first.

Modes

  • trim-video

Provider endpoints: fal-ai/workflow-utilities/trim-video.

Request fields

FieldTypeRequiredDefaultRule
duration_secondsnumberno—0.1–180
end_time_secondsnumberno—0–180
quote_idstringno—UUID
quote_onlybooleannofalse—
start_time_secondsnumberyes—0–180
video_urlstringyes—https URL; ≤ 4,096 characters
wait_timeout_secondsintegerno00–60
webhook_urlstringno—https URL; ≤ 4,096 characters

The schema is strict. A field that is not in this table gets 400 unsupported_option. The field names are the roasOS role names. One role has one name in every family.

Media

This endpoint accepts these media roles:

  • video_url — the source video
RoleItemsMaximum sizeContent typesDuration
video_url≤ 1100 MBvideo/mp40–180 s

Every other role is refused: avatar_id, elements, product_id, product_images, references, reference_images, image_url, end_image_url, scene_id, scene_image, video_urls, audio_urls, audio_url, voice_id. A refused role gets 400 unsupported_option.

Each media URL must be an immutable object on https://cdn.roasos.com that your workspace owns. Any other URL gets 400 reference_media_not_workspace_owned. Refer to Reference media and uploads to learn how to put a file there.

Prompt

None. This operation takes no prompt.

All three numbers are seconds. start_time_seconds is required, and 0 means "from the top" — there is no default, because the provider would otherwise start the cut at 1 second on its own. State exactly one of end_time_seconds (an absolute point, which must be past the start) or duration_seconds (a length measured from the start). The provider ignores duration when end_time is present, so sending both is refused rather than half-honoured.

Not exposed

These catalog entries describe omitted inputs, pinned values and source constraints. They do not imply that the provider accepts every listed field.

  • start_time — pinned to fal defaults it to 1; this door requires an explicit value (0 is allowed) and always sends it.
  • duration — pinned to fal defaults it to 2 and ignores it beside end_time; this door requires exactly one of end_time/duration and sends only that one.

Result

The result kind is video. Always present: url.

{
  "data": {
    "id": "gen_…",
    "kind": "video",
    "model": "trim-video",
    "status": "completed",
    "result": {
      "url": "https://cdn.roasos.com/workspaces/ws_01/result"
    }
  }
}

The files are immutable objects on https://cdn.roasos.com. A result URL is a valid media input for your next request.

Example

The three steps are always the same: quote, run, poll.

# 1. Quote. Nothing is spent.
curl -X POST https://api.roasos.com/v1/assembly/trim-video \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-trim-video-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_only":true,"start_time_seconds":0,"video_url":"https://cdn.roasos.com/workspaces/ws_01/uploads/video_url.mp4"}'
# 200 { "data": { "kind": "quote", "quote_id": "q_7Hk...", "credits": 1, "expires_at": "...",
#        "confirmation": { "model": "trim-video", "example": "per_operation" } } }

# 2. Run. Same body, same Idempotency-Key, quote_id in place of quote_only.
curl -X POST https://api.roasos.com/v1/assembly/trim-video \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-trim-video-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_id":"q_7Hk...","start_time_seconds":0,"video_url":"https://cdn.roasos.com/workspaces/ws_01/uploads/video_url.mp4"}'
# 201 { "data": { "id": "gen_...", "status": "queued", "credits_reserved": 1 } }

# 3. Poll, then read the result.
curl https://api.roasos.com/v1/jobs/gen_.../status -H "Authorization: Bearer roasos_sk_live_..."
curl https://api.roasos.com/v1/jobs/gen_.../result -H "Authorization: Bearer roasos_sk_live_..."

Today

The endpoint is POST /v1/assembly/trim-video.

It is live.

See also

  • llms.txt for this model — the same facts as one plain-text file for an agent.
  • GET https://api.roasos.com/v1/catalog/trim-video — the machine-readable form: enums, defaults, limits and prices. Refer to the API reference.
  • Jobs — how to poll a job and read its result.
  • Provider endpoints: fal-ai/workflow-utilities/trim-video.

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