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post/transcribe

Convert songs and instrument stems to MIDI

Send a full song or an isolated instrument stem. Your app or agent gets editable MIDI notes for arranging, practice, playback, analysis, or sound replacement.

Get an API keyView examples

How this endpoint works

Use this API to build an audio-to-MIDI converter, transcription tool, practice app, arrangement assistant, or DAW feature. Split a full song into stems first when users need separate bass, drum, vocal, and instrument MIDI. MuScriptor supports automatic or selected instruments and optional note quantization.

  1. 1

    Choose the song or stem

    Pass the audio ID and optionally select one isolated stem or the instruments to detect.

  2. 2

    Wait for transcription

    Save id and poll the MIDI transcription job until it finishes or fails.

  3. 3

    Download the MIDI

    Download the .mid file and open it in your app, DAW, piano roll, or notation pipeline.

Common use cases

Choose this operation when it matches the source and result your pipeline needs.

Learn an instrument part

Turn an isolated bass, drum, vocal, or instrument stem into notes users can inspect and practice.

Reorchestrate a song

Import the MIDI into a DAW, change instruments, correct notes, and reshape the arrangement.

Replace sounds with a VST

Use the detected notes to trigger drums, synths, samplers, or another instrument in your software.

Processing used by 80,000+ music makers

Results people rely on

“It can bring back clarity without making everything sound too artificial or overprocessed. Stem separation is also surprisingly clean.”
R

R.

Audio restoration and stem separation

“Does amazing job in restoring Audio from bad quality MP3s and badly extracted audio from CDs. Always my go to for audio restoration.”
N

N.

MP3 and CD audio restoration

“Amazing tool for audio. Clean, simple, and effective. I would spend hours in RX to get the same results. Give it a try. I can save you hours of production time.”

Dan Campbell ~Riffster

“Easy to use and high quality results.”
B

Bjark

Hear audio-to-MIDI results

These MIDI transcriptions were shared by users of the same processing system exposed through the API.

More User Examples

Choose how the MIDI tracks are created

MuScriptor Large

model="muscriptor-large"

This model transcribes music into a MIDI file with multiple instruments. Its large training dataset and the computing power of the GPU it uses give it impressive performance. Note: this model does not generate note velocities.

Parameters
instrument_modeInstrument track modestring

Controls how instrument tracks are created. auto detects instruments, select uses the instruments list as guidance, and combine_melodic combines melodic parts. Omit it to infer the mode from instruments.

Allowed values

  • autoAutoDefaultRecommended
  • selectSelect instruments
  • combine_melodicCombine melodic instruments
instrumentsInstrument guidanceArray<string>

Guides which instrument tracks MuScriptor should transcribe. Transkun always produces one acoustic-piano track. Leave the list empty to detect instruments automatically. Use supported instrument IDs such as acoustic_guitar or their display names, such as Acoustic Guitar; names are normalized before processing. Accepts up to 128 names, each between 1 and 64 characters.

Allowed values

  • electric_bassBass
  • acoustic_bassAcoustic Bass
  • drumsDrums
  • acoustic_guitarAcoustic Guitar
  • clean_electric_guitarClean Electric Guitar
  • distorted_electric_guitarDistorted Electric Guitar
  • acoustic_pianoAcoustic Piano
  • electric_pianoElectric Piano
  • organOrgan
  • synth_leadSynth Lead
  • synth_padSynth Pad
  • synth_stringsSynth Strings
  • orchestra_hitOrchestra Hit
  • string_ensembleString Ensemble
  • violinViolin
  • violaViola
  • celloCello
  • contrabassContrabass
  • orchestral_harpOrchestral Harp
  • voiceVoice
  • chromatic_percussionXylophone
  • timpaniTimpani
  • brass_sectionBrass Section
  • trumpetTrumpet
  • tromboneTrombone
  • french_hornFrench Horn
  • tubaTuba
  • soprano_and_alto_saxSoprano & Alto Saxophone
  • tenor_saxTenor Saxophone
  • baritone_saxBaritone Saxophone
  • flutesFlutes
  • clarinetClarinet
  • oboeOboe
  • english_hornEnglish Horn
  • bassoonBassoon
quantize_precisionNote quantizationstring | null

Sets the timing grid for MIDI note starts and releases. Use null to preserve the timing detected by the transcription model.

Allowed values

  • 1/4
  • 1/8
  • 1/8T
  • 1/16
  • 1/16T
  • 1/32
  • 1/32T

Transkun V2

model="transkun"

This high-quality model turns a piano performance into a MIDI track. It captures the notes, their velocities, and pedal controls. Magical for piano, but not useful for other instruments.

Parameters
quantize_precisionNote quantizationstring | null

Sets the timing grid for MIDI note starts and releases. Use null to preserve the timing detected by the transcription model.

Allowed values

  • 1/4
  • 1/8
  • 1/8T
  • 1/16
  • 1/16T
  • 1/32
  • 1/32T

Code examples

Server-side example

JavaScript (Node.js)
import { writeFile } from "node:fs/promises";

const API_URL = "https://api.neuralanalog.com";
const API_KEY = process.env.NEURALANALOG_API_KEY;

async function waitForCompletion(objectType, objectId) {
  while (true) {
    const response = await fetch(`${API_URL}/status/${objectType}/${objectId}`, {
      headers: { "X-API-Key": API_KEY },
    });
    if (!response.ok) {
      throw new Error(`Status check failed with ${response.status}`);
    }

    const status = await response.json();
    if (status.is_failed) {
      throw new Error(status.error_message || `${objectType} processing failed`);
    }
    if (status.is_complete) {
      return status;
    }
    await new Promise((resolve) => setTimeout(resolve, 5000));
  }
}

const requestResponse = await fetch(`${API_URL}/transcribe`, {
  method: "POST",
  headers: {
    "X-API-Key": API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
  "audio_id": "6c62f8e7-02a3-48c0-a5b5-5de87ed9c31a",
  "model": "muscriptor-large",
  "instrument_mode": "auto",
  "quantize_precision": "1/16"
}),
});
if (!requestResponse.ok) {
  throw new Error(`Transcription request failed with ${requestResponse.status}`);
}

const result = await requestResponse.json();
const jobId = result["id"];
const status = await waitForCompletion("transcription", jobId);

const downloadResponse = await fetch(
  `${API_URL}/download/transcription/${jobId}`,
  { headers: { "X-API-Key": API_KEY }, redirect: "follow" },
);
if (!downloadResponse.ok) {
  throw new Error(`Download failed with ${downloadResponse.status}`);
}
await writeFile("transcription.mid", Buffer.from(await downloadResponse.arrayBuffer()));

Parameters

Send the API key from a trusted server. Never expose it in client-side JavaScript.

JSON request body

audio_id
requiredstring

Identifies the parent audio to transcribe.

model
optionalstring

Selects MuScriptor Large for multi-instrument transcription or Transkun for piano transcription.

"muscriptor-large""transkun"

Default: "muscriptor-large"

instrument_mode
optionalstring

Controls how instrument tracks are created. auto detects instruments, select uses the instruments list as guidance, and combine_melodic combines melodic parts. Omit it to infer the mode from instruments.

"auto""select""combine_melodic"

Default: "auto"

chunking
optionalstring

Controls MuScriptor scheduling. overlap uses overlapping 5-second windows with non-overlapping 4-second output cores; continuous uses one sequential lane of non-overlapping 5-second chunks; lane_interleave batches independent 30-second-or-longer lanes and propagates held notes within each lane.

"overlap""continuous""lane_interleave"

Default: "lane_interleave"

instruments
optionalarray<string>

Guides which instrument tracks MuScriptor should transcribe. Transkun always produces one acoustic-piano track. Leave the list empty to detect instruments automatically. Use supported instrument IDs such as acoustic_guitar or their display names, such as Acoustic Guitar; names are normalized before processing. Accepts up to 128 names, each between 1 and 64 characters.

Example: ["acoustic_piano","electric_bass"]

quantize_precision
optionalstring | null

Sets the timing grid for MIDI note starts and releases. Use null to preserve the timing detected by the transcription model.

"1/4""1/8""1/8T""1/16""1/16T""1/32""1/32T"
source_transcription_id
optionalstring | null

Transcription rendered into temporary_mix_key; retained as source lineage.

source_effects_applied
optionalboolean | null

Whether the rendered source includes FX; false preserves live FX when selecting the output.

stem_id
optionalstring | null

Selects one stem from the parent audio as the transcription source.

upscaled_id
optionalstring | null

Selects a restored version of the parent audio as the source.

mastered_id
optionalstring | null

Selects a mastered version of the parent audio as the source.

temporary_mix_key
optionalstring | null

Short-lived Current Main Mix or Current All Stems Mix R2 source key.

selection
optionalobject | null

Limits transcription to a start and end time in seconds. Omit it to transcribe the full selected source.

Successful response

200Successful Response
id
requiredstring

ID of the queued transcription.

Example: "d66cf940-bf26-45bb-80f7-332f26b6859a"

status
requiredstring

Queueing status for the transcription job.

Example: "starting"

message
requiredstring

Human-readable queueing result.

Example: "MIDI transcription started successfully"

Errors

A missing or invalid X-API-Key returns an authentication error. Validation errors use the declared 422 response below.
422Validation Error
detail
optionalarray<object>

No description provided.

Next steps

pollDownload the completed MIDISeparate instruments firstPreview MIDI pipelines