Audio to MIDI

Overview

AudioPod’s audio-to-MIDI engine transcribes bass, vocals, and piano in a recording into note-level MIDI — bass is the strongest instrument. Guitar is supported too but is opt-in/experimental. Use it standalone on a full mix (we split it into stems first, then transcribe each requested stem) or as an add-on to a stem-separation job you already ran (transcribe-only, no re-split).

This is a starting-point transcription, not a note-perfect one. Bass is the strongest instrument; expect to tidy timing and note lengths by ear in your DAW. Dynamics (velocity) are approximate. Drums aren’t transcribed yet — a requested drums (or other) stem is accepted but comes back in skipped_stems. Guitar is opt-in and experimental — it over-detects on busy mixes, so it isn’t requested by default. Detected tempo is surfaced as detected_tempo_bpm.

Key Features

Standalone or add-on: convert a raw file/URL, or transcribe stems from an existing stem-separation job
Per-stem + multitrack output: individual .mid per stem, plus a merged multitrack .mid with tempo metadata
Tempo detection: auto-detected via beat tracking, or pass an explicit tempo_bpm override
Presigned downloads: direct URLs for every output file

Installation

Python
Node.js

pip install audiopod

npm install audiopod

Authentication

Get your API key from the API Keys Dashboard.

Python
Node.js
cURL

from audiopod import AudioPod

client = AudioPod(api_key="ap_your_api_key")
# Or set AUDIOPOD_API_KEY environment variable

import AudioPod from 'audiopod';

const client = new AudioPod({ apiKey: 'ap_your_api_key' });
// Or set AUDIOPOD_API_KEY environment variable

export AUDIOPOD_API_KEY="ap_your_api_key"
# Use -H "X-API-Key: $AUDIOPOD_API_KEY" in requests

Convert From a File or URL

Standalone conversion splits the mix into stems, then transcribes each requested stem. Provide either file or url — not both. stems defaults to ["bass", "vocals", "piano"] — the strongest instruments — when omitted. guitar is supported but opt-in/experimental (it over-detects on busy mixes), so pass it explicitly if you want it. drums and other are accepted but are never transcribed — they always come back in skipped_stems.

cURL (file)
cURL (URL, with guitar opt-in)
Python
Node.js

curl -X POST "https://api.audiopod.ai/api/v1/midi/convert" \
  -H "X-API-Key: $AUDIOPOD_API_KEY" \
  -F "file=@/path/to/song.mp3"

curl -X POST "https://api.audiopod.ai/api/v1/midi/convert" \
  -H "X-API-Key: $AUDIOPOD_API_KEY" \
  -F "url=https://youtube.com/watch?v=VIDEO_ID" \
  -F 'stems=["bass","vocals","piano","guitar"]'

from audiopod import AudioPod

client = AudioPod(api_key="ap_your_api_key")

# From a local file (or pass url="https://.../song.mp3")
# Default stems: bass, vocals, piano
job = client.midi.convert(file="/path/to/song.mp3")

print(f"Multitrack: {job['merged_midi_url']}")
for stem, url in (job["midi_urls"] or {}).items():
    print(f"  {stem}: {url}")

import AudioPod from 'audiopod';

const client = new AudioPod({ apiKey: 'ap_your_api_key' });

// From a local file (or pass { url: 'https://.../song.mp3' })
// Default stems: bass, vocals, piano
const job = await client.midi.transcribe({ file: '/path/to/song.mp3' });

console.log(`Multitrack: ${job.merged_midi_url}`);
for (const [stem, url] of Object.entries(job.midi_urls ?? {})) {
  console.log(`  ${stem}: ${url}`);
}

Options

Tunables forwarded to the audio-to-MIDI engine, passed as options (a JSON object):

Field	Type	Default	Description
`onset_threshold`	float (0.05–0.95)	`0.5`	Note-onset detection sensitivity
`frame_threshold`	float (0.05–0.95)	`0.3`	Frame-level pitch confidence threshold
`min_note_len_ms`	float (10–2000)	`128.0`	Minimum note duration in milliseconds
`tempo_bpm`	float (30–300) or `null`	`null` (auto-detect)	Override the detected tempo

Convert From an Existing Stem-Separation Job

If you already ran stem separation, transcribe its output directly — no re-split, so it bills the add-on rate only. stems must be a subset of the stems the source job produced, and defaults to all of them when omitted — drums/other stems still come back in skipped_stems (never transcribed), and guitar remains opt-in/experimental.

cURL
Python
Node.js

curl -X POST "https://api.audiopod.ai/api/v1/midi/convert/from-stems/5512" \
  -H "X-API-Key: $AUDIOPOD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"stems": ["vocals", "bass"]}'

stem_job = client.stems.separate(file="/path/to/song.mp3", mode="six")

job = client.midi.convert_from_stem_job(
    stem_job_id=stem_job["id"],
    stems=["vocals", "bass"],
)
print(job["merged_midi_url"])

const stemJob = await client.stems.separate({ file: '/path/to/song.mp3', mode: 'six' });

const job = await client.midi.convertFromStemJob(stemJob.id, {
  stems: ['vocals', 'bass'],
});
console.log(job.merged_midi_url);

If the source stem job’s output has expired under your plan’s retention window, this returns 410 Gone — re-run stem separation first.

Job Status & Stages

cURL
Python
Node.js

curl -X GET "https://api.audiopod.ai/api/v1/midi/status/JOB_ID" \
  -H "X-API-Key: $AUDIOPOD_API_KEY"

status = client.midi.get_job(job_id)
print(f"Status: {status['status']}, stage: {status['stage']}")

const status = await client.midi.status(jobId);
console.log(`Status: ${status.status}, stage: ${status.stage}`);

stage tracks pipeline progress for a PROCESSING job:

Stage	Description
`split`	Separating the mix into stems (standalone mode only)
`transcribe`	Running the audio-to-MIDI engine on each requested stem
`merge`	Building the merged multitrack `.mid`

Other Job Endpoints

# List jobs
curl -X GET "https://api.audiopod.ai/api/v1/midi/jobs?skip=0&limit=50" \
  -H "X-API-Key: $AUDIOPOD_API_KEY"

# Delete a job (purges its outputs)
curl -X DELETE "https://api.audiopod.ai/api/v1/midi/jobs/JOB_ID" \
  -H "X-API-Key: $AUDIOPOD_API_KEY"

Output Format

Completed Job Response:

{
  "id": 5512,
  "status": "COMPLETED",
  "progress": 100,
  "stage": "merge",
  "mode": "standalone",
  "source_job_id": null,
  "stems_requested": ["bass", "vocals", "piano"],
  "midi_urls": {
    "bass": "https://media.audiopod.ai/...",
    "vocals": "https://media.audiopod.ai/...",
    "piano": "https://media.audiopod.ai/..."
  },
  "merged_midi_url": "https://media.audiopod.ai/...",
  "stem_urls": {
    "bass": "https://media.audiopod.ai/...",
    "vocals": "https://media.audiopod.ai/..."
  },
  "detected_tempo_bpm": 118.0,
  "skipped_stems": [],
  "failed_stems": null,
  "duration": 214,
  "original_filename": "song.mp3",
  "created_at": "2026-07-24T12:39:37.379848Z",
  "completed_at": "2026-07-24T12:41:02.104213Z"
}

midi_urls — presigned download URL per transcribed stem’s .mid file
merged_midi_url — a single multitrack .mid with all transcribed stems as separate tracks plus tempo metadata
stem_urls — the separated stem audio (standalone mode only, so you can preview what was transcribed)
skipped_stems — stems requested but not transcribed (always drums and other, if requested — they’re not part of the transcribable set)
failed_stems — {stem: error_message} for any stem the engine couldn’t transcribe; the job still completes if at least one stem succeeded

All download URLs are presigned and expire — call the status endpoint again to mint fresh ones.

Status Codes

Status	Description
`PENDING`	Job queued, waiting for worker
`PROCESSING`	Splitting and/or transcribing — see `stage`
`COMPLETED`	At least one stem transcribed — download URLs available
`FAILED`	No stem could be transcribed — check `error_message`

Pricing

See audiopod.ai/pricing for current rates, or check your estimated cost before converting via the API Wallet.

Audiobook

Podcast

Audio Processing

Speech

Voice

Music

Utilities

Overview

Key Features

Installation

Authentication

Convert From a File or URL

Options

Convert From an Existing Stem-Separation Job

Job Status & Stages

Other Job Endpoints

Output Format

Status Codes

Pricing

Next Steps

Stem Separation

API Wallet

​Overview

​Key Features

​Installation

​Authentication

​Convert From a File or URL

​Options

​Convert From an Existing Stem-Separation Job

​Job Status & Stages

​Other Job Endpoints

​Output Format

​Status Codes

​Pricing

​Next Steps

Stem Separation

API Wallet

Overview

Key Features

Installation

Authentication

Convert From a File or URL

Options

Convert From an Existing Stem-Separation Job

Job Status & Stages

Other Job Endpoints

Output Format

Status Codes

Pricing

Next Steps