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black-forest-labs/flux-3/upscaleFrom 79.2 credits per second· Upscale Video

FLUX 3 upscale enlarges an MP4 of up to 20 seconds by 1.5 to 3 times, keeping its sound, in a faithful precise mode or a detail-rebuilding creative mode.

Call it with the model name black-forest-labs/flux-3/upscale on POST /jobs/createTask, from 79.2 credits per second ($0.79). New accounts get 30 free credits to try it in the Playground first.

  • Create Video
  • Image to Video
  • Extend Video
  • Upscale Video
  • Up to 1080p
  • 5–20s clips
  • Sound included
  • Start and end frames
  • 7 aspect ratios
by Black Forest LabsGet API keyFLUX 3 examples and prompts →

Introduction

FLUX 3 Video upscale enlarges a finished video clip by 1.5 to 3 times. It accepts an MP4 of up to 20 seconds, keeps the aspect ratio and the original sound, and offers a precise mode that stays faithful to the source and a creative mode that rebuilds fine detail.

Choose a mode by starting material

What you haveMode
a written briefFLUX 3 Text to video
a still to animate, with an optional last frameFLUX 3 Image to video
a clip to continueFLUX 3 Video extend
a clip to enlargeFLUX 3 Video upscale

Key features

Precise and creative

Precise only sharpens: in our 2x test, stubble, hair edges and fabric folds got crisper with no invented detail.

Sound kept

The original audio track stays with the enlarged clip.

Request parameters

ParameterRequiredDescription
promptNoOptional, creative mode only: the detail you want added, such as skin texture or fabric weave.
upscale_factorNoHow much bigger the result gets. ≥ 1.5 · ≤ 3 · Default: 2
upscale_modeNoprecise stays faithful to the source; creative also rebuilds fine detail and costs more. precise · creative · Default: precise
video_urlYesThe clip to work on.

Pricing

Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.

OptionCredits per second≈ USD
upscale_mode precise79.2$0.79
upscale_mode creative113.76$1.14

For an exact number before you run, send the same body to POST /jobs/quote.

Use cases

Preparing a final cut

Render and edit at 720p, then enlarge only the clips you keep.

Rescuing a draft

Bring a good draft-tier clip up to a larger size.

Delivery sizes

Pick a factor between 1.5x and 3x to match your output.

Prompt guide & pro tips

Use creative sparingly

Only choose it when the footage needs detail rebuilt, and describe the texture you want in the prompt.

Do not expect missing detail to return

Small elements that are blurred in the source stay blurred.

Plan for time

Our 2x test of a five-second clip took about 17 minutes.

Mind the file size

A 2x clip came out near 17 MB for five seconds.

API quick start

Call the FLUX 3 API in three steps

  1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
  2. Send the request. POST /jobs/createTask with model black-forest-labs/flux-3/upscale and an input object that follows the parameter table. The response returns a task ID straight away.
  3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.
# 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": "black-forest-labs/flux-3/upscale",
  "input": {
    "video_url": "https://media.popnow.ai/effects/flower-bloom-1abd6efb.mp4",
    "upscale_mode": "precise"
  }
}'

# 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"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

FLUX 3 API questions

How much does the FLUX 3 API cost?

FLUX 3 starts at 79.2 credits ($0.79) per second with Upscale Video, its cheapest task. Prices by option: precise 79.2 credits per second, creative 113.76 credits per second. Credits are the same as on the website (1 credit = $0.01), new accounts get 30 free credits, and failed tasks are refunded.

What is the model name for FLUX 3 in the API?

Put black-forest-labs/flux-3/text-to-video for Create Video; black-forest-labs/flux-3/image-to-video for Image to Video; black-forest-labs/flux-3/video-extend for Extend Video; black-forest-labs/flux-3/upscale for Upscale Video in the model field of POST /jobs/createTask.

Does video extend return the whole clip?

No. The result contains only the newly generated segment, not your source clip, so join the two in an editor. The new segment starts from the last frame of the source; in our test it began with a short dissolve and then moved on to the next action.

Can I make one long 20 second shot?

You can ask for up to 20 seconds, but the model may still cut or dissolve inside a clip, especially when the light or the action changes a lot. For control, make shorter clips and chain them with extend.

Can I give it a last frame?

Yes, on image to video. The clip moves from the first image to the last. If the two frames differ a lot in light or place, the model may use a hard cut in the middle rather than a gradual change, so keep the frames close when you want a smooth move.

What are the limits of the FLUX 3 API?

Prompt length (characters): 5,000; Longest input clip: 20 s. Requests outside these limits are rejected before anything is charged.

Can I try FLUX 3 without writing code?

Yes. The Playground runs FLUX 3 on your PopNow credits, needs no API key, and shows the matching code for every run.

All FLUX models

LTX 2.5 reaches 4K natively and also runs 20 seconds. FLUX 3 adds a cheap draft tier plus extend and upscale in one place.

More about FLUX 3