MiniMax H3 Max API

Introduction

MiniMax H3 Max Video extend continues a clip you already have. Send it as video_url with a prompt for what happens next. The final frame of your clip becomes the opening frame of a new MiniMax H3 Max image-to-video shot of 5 to 15 seconds, and the two are joined into one MP4: your original first, then the continuation, with the repeated seam frame removed. The new segment also comes back as its own file, so you can keep extending or edit the pieces separately.

Key features

Continuity comes from the last frame

Wardrobe, set, light and where everyone stands carry over because the new segment literally starts on your final frame. Motion does not carry over the same way: the model sees one still, not the whole clip, so describe the movement you want to continue instead of assuming it will keep its speed or direction.

One file back, plus the new piece on its own

The joined MP4 keeps your clip’s frame rate and its framing, with no black bars. To line the seam up, the picture may be trimmed or adjusted by a few percent at the edges. If the model returns a noticeably different shape, the new segment is scaled to fill your frame and centered, cropping what spills over. The new segment comes with sound generated in the same pass; sound from your source stays, and the seam is blended over a fraction of a second. If one side is silent, the other is padded with silence. The second asset in the output is the new segment alone, with the role segment, ready for another extend or for an editor.

An optional closing frame

last_image_url is optional. Send an image and the new segment comes to rest on it; leave it out and the ending is free. The closing frame tightens the ending only, and the longer the segment, the further the middle can drift from it.

Request parameters

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.

Each task is rounded up to whole credits, so one run at the lowest tier costs 38 credits for a 5-second clip ($0.38).

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

Use cases

Lengthen a shot that ended too early

A product turntable that stops before the label faces camera, or a walk that cuts before the subject reaches the door. Extend it by a few seconds and describe only the remaining motion.

Build a longer sequence step by step

One request produces at most 15 seconds. Because every step starts from a single frame, watch each seam before stacking the next one.

Prompt guide & pro tips

Describe the next beat, not the whole scene

The frame already fixes who and where, so spend the prompt on the action that follows, the camera move and the sound. Repeat the camera language your clip ended on, such as a slow push in or a locked shot, so the seam reads as one take.

Trim before you extend

The last frame is the only thing the model sees, so a blurred, mid-cut or heavily compressed ending carries straight into the continuation. Cut your source on a clean, sharp frame first. Sources of up to 60 seconds are accepted as MP4, MOV or WebM.

Keep the resolution consistent

The resolution only decides how sharp the new segment is generated, so a lower setting makes the new part look softer than the original.

API quick start

Call the MiniMax H3 Max 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 minimax/h3-max/video-extend 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": "minimax/h3-max/video-extend",
  "input": {
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "duration_seconds": 8,
    "resolution": "768p",
    "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"

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

MiniMax H3 Max API questions

All MiniMax models

MiniMax H3 adds reference-to-video and a 2K tier. Max is the quicker option when 768p is enough.

• MiniMax H3 APIExpressive clips with audio, up to 2KFrom 28 credits for a 5-second clip
• MiniMax Speech 2.8 HD APIHigh-fidelity speech in 400+ voices with emotion controlFrom 18 credits per 1,000 characters
• MiniMax Music 3.0 APIFinished stereo songs, with vocals or instrumentalFrom 27 credits per run
• MiniMax H3 Singularity LoRA APICommunity-tuned H3 video that loads your own LoRAsFrom 45 credits for a 5-second clip
• MiniMax H3 Max APIFast clips with ambience, effects and musicFrom 38 credits for a 5-second clip
• MiniMax H3 LoRA APIMiniMax H3 video with sound and up to three of your LoRAsFrom 38 credits for a 5-second clip
• MiniMax H3 Image LoRA APIH3 stills and edits with up to three of your LoRAsFrom 7 credits per image
• MiniMax Speech 2.8 Turbo APIFast speech in 400+ voices with emotion controlFrom 11 credits per 1,000 characters

Other video APIs

• Seedance 2.5 APIByteDance's newest: 30-second clips with native audioFrom 56 credits for a 5-second clip
• Kling 3.0 API4K clips, multi-shot cuts and motion controlFrom 51 credits for a 5-second clip
• Vidu Q4 Preview APIUp to 4K clips with sound and spoken dialogueFrom 34 credits for a 5-second clip
• Wan 3.0 APIUp to 30-second clips with synced audioFrom 34 credits for a 5-second clip
• Kling O3 APIKling’s unified model: create, animate, reference and edit up to 4KFrom 51 credits for a 5-second clip
• LTX 2.5 APILong 20-second takes up to 4K with a soundtrackFrom 68 credits for a 5-second clip

More about MiniMax H3 Max

Try it

MiniMax H3 Max AI Video Generator onlineCreate videos with MiniMax H3 Max in PopNow

Docs

MiniMax H3 Max model ID and input schema in the API docsPopNow API quickstart: your first request in five minutesImage to video guide for the PopNow APIWebhooks: get MiniMax H3 Max results without polling