# Remix Pack Builder

Turn one music track into a complete remix pack: BPM, key (with Camelot), cue points, four Demucs stems, an MP3 preview, and a metadata JSON — all in one ZIP.

> Canonical page: https://elysiatools.com/en/tools/audio-remix-pack-builder

- **Category:** Media

- **Keywords:** remix pack, stems, demucs, bpm, musical key, camelot, cue points, dj tools, acapella, preview mp3

## Overview

Assembles the assets a remix or edit session needs. Analysis runs first: tempo and beat grid, Krumhansl-Schmuckler key with Camelot wheel code, and DJ cue points (structure-novelty method: checkerboard-kernel novelty on beat-synchronous features, 4-bar period snapping, salience filtering, and mix-in/drop/breakdown/mix-out labeling). Optional stems come from the local HT-Demucs four-stem ONNX model (drums, bass, other, vocals) encoded in your chosen format; source separation is not lossless, so treat stems as a starting point. A preview MP3 at 128/192/320 kbps plus remix-info.json and a README round out the ZIP. Track length is capped at 3 minutes per job, matching the separation model budget.

## Inputs

- **Music track** (file)
- **Stem format** (select)
- **Include stems (Demucs)** (checkbox)
- **Include cue exports** (checkbox)
- **Preview bitrate** (select)

## When to use

- Preparing isolated audio stems, BPM data, and Camelot key values for DAW remix sessions.
- Extracting automated DJ cue points such as drops, breakdowns, and mix-in/out markers.
- Creating compact track preview packages with accompanying JSON metadata and separated acapellas or instrumentals.

## How it works

- Upload a music file up to 100 MB and 3 minutes in length.
- Select your target stem format (FLAC, WAV, MP3, M4A, or OGG Vorbis), preview bitrate, and whether to include Demucs stem separation and cue exports.
- The engine analyzes tempo, beat grids, musical key, and structural cue points while running local HT-Demucs 4-stem separation if enabled.
- Download the compiled ZIP archive containing isolated stems, cue files, a preview MP3, remix-info.json, and a README.

## Use cases

- Music producers isolating vocal and drum stems to build bootlegs or official remixes.
- DJs analyzing unfamiliar tracks for Camelot key matching, beat grids, and cue point markers.
- Audio creators archiving song stems and metadata into standardized ZIP packages.

## Frequently asked questions

### What audio stems does the tool generate?

When stem separation is enabled, the tool extracts four separate audio tracks: drums, bass, vocals, and other instruments using HT-Demucs.

### What is the maximum supported track length?

Audio inputs are limited to a maximum duration of 3 minutes per job.

### Which audio formats are available for stem output?

You can export stems in FLAC, WAV, MP3, M4A (AAC), or OGG Vorbis format.

### How are musical key and cue points calculated?

Keys are detected via the Krumhansl-Schmuckler algorithm with Camelot wheel codes, and cue points are identified using beat-synchronous novelty detection snapped to 4-bar periods.

### Can I skip stem separation to speed up processing?

Yes. Uncheck 'Include stems' to perform only BPM, key, cue point analysis, and preview generation without running the neural separation model.

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## Samples

- [Copyright-Free FLAC Audio Samples](https://elysiatools.com/en/samples/flac-samples): Lossless FLAC audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
- [Copyright-Free MP3 Audio Samples](https://elysiatools.com/en/samples/mp3-samples): Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio
- [Copyright-Free WAV Audio Samples](https://elysiatools.com/en/samples/wav-samples): Uncompressed PCM WAV audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
- [WebRTC Real-Time Communication Samples](https://elysiatools.com/en/samples/webrtc-samples): Comprehensive WebRTC samples for peer-to-peer audio/video communication, data channels, screen sharing, and signaling server implementation