Demucs
Live on the APIdemucs$0.01794/1-min song
- Input → output
- AudioStems
- Longest input
- 15 min
- Stems
- Vocals + instrumental · Vocals, drums, bass, other
Demucs API prices
Every tier we sell, next to the model maker's official price.
| Tier | Opennan | Official |
|---|---|---|
| 1-min song, +$0.00299 per extra minute | $0.01794 | No official price |
The maker doesn't sell this exact model on its own API (open weights, or retired there), so there is no official price to compare.
Call Demucs from your code
Everything for your first call is on this page: the endpoint, a key, the request and every parameter.
https:/Get an API key
Create a key in the console. It uses the same balance as the playground.
Create a keySend your first request
The same request the playground sends. Set OPENNAN_KEY to your key.
curl https://api.opennan.com/v1/audio/separations \ -H "Authorization: Bearer $OPENNAN_KEY" \ -H "Content-Type: application/json" \ -d '{"model":"demucs","audio_url":"https://example.com/song.mp3","stems":"vocals"}' # Then poll until "status" is "succeeded" or "failed": curl https://api.opennan.com/v1/tasks/<task id> -H "Authorization: Bearer $OPENNAN_KEY"Poll the task
The call answers right away with a task id. Ask for the task until it finishes:
GEThttps:// api.opennan.com/ v1/ tasks/ {id} - queued
- Waiting for a worker
- running
- Being made
- succeeded
- Done: outputs[].url holds the files
- failed
- Failed: you are not charged
Parameters
Built from the live catalog: every value listed here is one the API accepts.
Errors and how to fix them
401Missing or wrong key
Send the header Authorization: Bearer with a key from the console.
402Balance too low
Add credit in Billing, then send the same call again.
400A value is not accepted
Read error.message: it names the field. Use a value from the parameter table.
429Too many requests
Wait a few seconds and try again, waiting longer after each 429.
Add Opennan to your AI app
One install gives your AI every Opennan tool: video, images, chat, voice, music, sound effects, 3D, captions and dubbing. Pick your app and follow the steps.
https:/Works in the Codex CLI, the Codex app and the Codex IDE extension: they share ~/.codex/config.toml. If the app or IDE does not see OPENNAN_KEY, use the config.toml option with your key in it. Codex asks before each tool call: approve it to go on.
Get an API key
Create a key in the console. It starts with sk- and uses the same balance as the website.
Create a keySave your key as OPENNAN_KEY
# macOS / Linux (zsh shown; bash: ~/.bashrc) echo 'export OPENNAN_KEY="sk-..."' >> ~/.zshrc source ~/.zshrc # Windows (PowerShell), then open a new terminal setx OPENNAN_KEY "sk-..."Install the Opennan plugin: the server plus a skill that teaches your AI to pick models, confirm prices and wait for results
codex plugin marketplace add Opennan/opennan-ai-plugin codex plugin add opennan@opennanOr add only the server
codex mcp add opennan --url https://api.opennan.com/v1/mcp --bearer-token-env-var OPENNAN_KEYOr add this to ~/.codex/config.toml
[mcp_servers.opennan] url = "https://api.opennan.com/v1/mcp" http_headers = { Authorization = "Bearer sk-..." }Check that opennan is listed
codex mcp listRestart Codex, then ask for anything
“Make a 5 second video of rain on a neon street, a song to go with it and a poster image.”
Replace sk-... with your own key and keep it private: anyone who has it can spend your balance. Your app can list the tools before you add a key; making anything needs one.
This tool from your AI
Once Opennan is added, your AI calls this tool with arguments like these.
- Tool
- separate_audio
- Example arguments
{ "model": "demucs", "audio_url": "https://example.com/song.mp3", "stems": "vocals" }
Demucs API questions
How much does the Demucs API cost?
Demucs API on Opennan: $0.01794 per 1-min song, +$0.00299 per extra minute. Prices are in US dollars per call, shown before you run, and every tier is in the price table.
What inputs does Demucs take?
Audio.
Which options can a call set?
Stems: vocals, all. Songs up to 15 minutes long.
How is it billed?
$0.01794 for a 1-minute song, plus $0.00299 for each extra minute of input audio.
What happens if a generation fails?
A failed task is refunded in full. You pay only for results.
How do I call Demucs from an AI agent?
Add the MCP server https://api.opennan.com/v1/mcp with your API key as a bearer token, then call the separate_audio tool with model "demucs". Or send a POST to https://api.opennan.com/v1/audio/separations.
Similar models
Other audio models you can call with the same key.