Inference Logoinference shell

Pika H3 Flex Audio Stems

Split the soundtrack of an audio or video file (up to 120s) into Dialogue, Music and Effect WAV stems with Pika's H3 Flex separator. Billed per stem second.

audio separationstemsaudio to audio
run in browser →run via APIrun with your agent
maker
pika
category
audio
input → output
audio → audio
runs via
api, javascript and python sdk, belt cli, mcp
updated
2026-11-08
price
$0.001/stem-sec (3 stems: dialogue, music, effect)

api reference

about

split the soundtrack of an audio or video file (up to 120s) into dialogue, music and effect wav stems with pika's h3 flex separator. billed per stem second.

get an api key

create one in settings → api keys. the examples read it from INFERENCE_API_KEY.

bash
1export INFERENCE_API_KEY="inf_your_key"

1. calling the api

install the client

nothing to install. any http client works; the examples use curl, and jq to read responses. every response wraps its result in a data field.

run and get result

send "wait": true to hold the connection until the task finishes. without it the call returns right away with the task still running.

bash
12# "wait": true holds the connection until the task finishes.3# the response is {"data": {"id", "status", "status_text", "output", ...}}4curl -X POST https://api.inference.sh/apps/run \5  -H "Authorization: Bearer $INFERENCE_API_KEY" \6  -H "Content-Type: application/json" \7  -d '{8    "app": "pika/pika-h3-flex-audio-stems",9    "input": {10      "audio": "https://example.com/file.png"11    },12    "wait": true13  }'

stream live updates

get real-time progress updates as the task runs. ideal for showing progress bars, partial results, or long-running tasks. send "stream": true and the response is a server-sent event stream that ends when the task does.

bash
12# "stream": true answers with server-sent events until the task finishes3curl -N -X POST https://api.inference.sh/apps/run \4  -H "Authorization: Bearer $INFERENCE_API_KEY" \5  -H "Content-Type: application/json" \6  -d '{7    "app": "pika/pika-h3-flex-audio-stems",8    "input": {9      "audio": "https://example.com/file.png"10    },11    "stream": true12  }'

run in the background

start the task and get its id back right away, then check on it later. for long tasks, or when you'd rather be called back, see webhooks.

bash
1# without "wait" the call returns the task right away (status 1, "received")2TASK_ID=$(curl -s -X POST https://api.inference.sh/apps/run \3  -H "Authorization: Bearer $INFERENCE_API_KEY" \4  -H "Content-Type: application/json" \5  -d '{6    "app": "pika/pika-h3-flex-audio-stems",7    "input": {8      "audio": "https://example.com/file.png"9    }10  }' | jq -r '.data.id')1112# later: read its state. done when status is 10 (completed), 11 (failed) or 12 (cancelled)13curl -s https://api.inference.sh/tasks/$TASK_ID \14  -H "Authorization: Bearer $INFERENCE_API_KEY" | jq '.data | {status, status_text, output}'

2. authentication

the api uses api keys for authentication. see the authentication docs for detailed setup instructions.

3. files

file inputs are automatically handled by the sdk. you can pass local paths, urls, or base64 data.

automatic upload

pass urls directly or use data uris for inline content.

bash
1# pass URLs or data URIs as input values2curl -X POST https://api.inference.sh/apps/run \3  -H "Authorization: Bearer $INFERENCE_API_KEY" \4  -H "Content-Type: application/json" \5  -d '{6    "app": "pika/pika-h3-flex-audio-stems",7    "input": {8      "image": "https://example.com/image.png",9      "audio": "data:audio/mp3;base64,..."10    },11    "wait": true12  }'

manual upload

you can also upload files manually and use the returned url.

bash
1# 1. create the file: the response has an upload_url and the file's uri2FILE=$(curl -s -X POST https://api.inference.sh/files \3  -H "Authorization: Bearer $INFERENCE_API_KEY" \4  -H "Content-Type: application/json" \5  -d '{"files": [{"filename": "image.png", "content_type": "image/png"}]}')67# 2. PUT the bytes to upload_url8curl -X PUT "$(echo "$FILE" | jq -r '.data[0].upload_url')" \9  -H "Content-Type: image/png" \10  --data-binary @image.png1112# 3. pass the uri as an input value13echo "$FILE" | jq -r '.data[0].uri'

4. webhooks

get notified when a task completes by providing a webhook url. when the task reaches a terminal state (completed, failed, or cancelled), a POST request is sent to your url with the task result.

bash
1curl -X POST https://api.inference.sh/apps/run \2  -H "Authorization: Bearer $INFERENCE_API_KEY" \3  -H "Content-Type: application/json" \4  -d '{5    "app": "pika/pika-h3-flex-audio-stems",6    "input": {7        "audio": "https://example.com/file.png"8    },9    "webhook": "https://your-server.com/webhook"10  }'

webhook payload

your endpoint receives a JSON POST with the task result:

json
1{2  "event": "task.completed",3  "timestamp": "2024-01-15T10:30:05Z",4  "data": {5    "id": "task_abc123",6    "short_id": "abc123",7    "status": 10,8    "status_text": "completed",9    "output": { ... },10    "created_at": "2024-01-15T10:30:00Z",11    "updated_at": "2024-01-15T10:30:05Z"12  }13}
eventstringtask.completed, task.failed or task.cancelled
timestampstringiso timestamp of the delivery
data.idstringtask id
data.short_idstringshort task id
data.statusnumberterminal status (10=completed, 11=failed, 12=cancelled, 13=rejected)
data.status_textstringthe status as a word: completed, failed or cancelled
data.outputobjecttask output (when completed)
data.errorstringerror message (when failed, omitted otherwise)
data.session_idstringsession id (when the task ran in a session, omitted otherwise)
data.created_atstringiso timestamp
data.updated_atstringiso timestamp

5. schema

input

audiostring(file)*

audio file, or a video with sound, up to 120 seconds.

channel_modestring

mono downmixes before separation; stereo keeps both channels in every stem. both bill the sum of stem seconds.

default: "mono"
options:"mono""stereo"

output

archivestring(file)

zip with every stem and the manifest, when pika returns one.

stemsarray

dialogue, music and effect wav files.

other audio apps

Fish Audio Drama 3

fish-audio/drama-3

$50.00/1M UTF-8 bytes

Eleven Flash v2.5

elevenlabs/eleven-flash-v2-5

$0.04/1K characters

Eleven Multilingual v2

elevenlabs/eleven-multilingual-v2

$0.08/1K characters

Eleven v3

elevenlabs/eleven-v3

$0.08/1K characters

Eleven v4 Turbo

elevenlabs/eleven-v4-turbo

$0.04/1K characters

more from pika

Pika H3 Flex (self-hosted)

pika/pika-h3-flex-oss

GPU time, billed per millisecond

Pika H3 Flex Upscale

pika/pika-h3-flex-upscale

$0.05-$0.14/sec (480p src), $0.03-$0.12/sec (768p src); 1080p/2K/4K targets

Pika H3 Flex Reference to Video

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$0.06/sec 480p, $0.12/sec 768p, $0.15/sec 1080p, $0.16/sec 2k, $0.20/sec 4k (output+input video sec). Stems: $0.001/sec

Pika H3 Flex

pika/pika-h3-flex

$0.02/sec 480p, $0.04/sec 768p, $0.07/sec 1080p, $0.08/sec 2K, $0.16/sec 4K; stems +$0.001/stem-sec

new models

  1. P

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    videoGPU time, billed per millisecond
  2. P

    Pika H3 Flex Upscale

    pika/pika-h3-flex-upscale

    video$0.05-$0.14/sec (480p src), $0.03-$0.12/sec (768p src); 1080p/2K/4K targets
  3. P

    Pika H3 Flex Reference to Video

    pika/pika-h3-flex-reference

    video$0.06/sec 480p, $0.12/sec 768p, $0.15/sec 1080p, $0.16/sec 2k, $0.20/sec 4k (output+input video sec). Stems: $0.001/sec
  4. P

    Pika H3 Flex

    pika/pika-h3-flex

    video$0.02/sec 480p, $0.04/sec 768p, $0.07/sec 1080p, $0.08/sec 2K, $0.16/sec 4K; stems +$0.001/stem-sec
  5. J

    JEV-9B

    autotrust/jev-9b

    decisionfrom $0.00055833/sec

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