Elospeed StemPacker

Your own stems as
Traktor stem files, in batches

StemPacker takes tracks you already have, a master and up to four stems per song, and packs them into one .stem.mp4 that Traktor loads as a stem file. No AI, no separation: your files are used exactly as they are. Hundreds of songs in one run, from your DAW, a 5.1 DVD or another tool.

⬇ Download for Windows View source on GitHub
  • Free & MIT licensed
  • Windows 10 / 11
  • Portable, no installation
  • No AI, your files as they are
  • Batch for whole collections
  • English, German, Spanish
Elospeed StemPacker 0.2
StemPacker window: preset 5.1 DVD, folders and name patterns for master and stems 1 to 4 with stem names Front, LFE, Center, Rear and their colours, below a list of three packed songs

Made for stems you already have

Traktor's own Stem Creator packs one song at a time. StemPacker does the same for a whole folder.

Folder and pattern per track

A star stands for the song name: * (DOWNMIX #1) finds the master, * (A) to * (D) the stems, even in different folders. One folder for everything works too (*_drums, *_bass …).

Your names and colours

Each stem gets the name and colour you set, for example Front, LFE, Center and Rear for 5.1 channels. Traktor shows them directly on the deck.

Tags and cover from the master

Title, artist, album, BPM, key, label and cover are copied from the master file. No title? The song name is used. No cover? cover.jpg or <song>.jpg from the folder.

AAC or lossless ALAC

AAC 320 kbit/s like Traktor's own stems, ALAC lossless 16 bit, or ALAC 24 bit at the original sample rate (still in testing).

Gaps handled

Songs without a finished master: mix it from the stems, without changing the level. A stem missing? The list shows the file name it looked for and a similarly named file, if there is one. Fill it with silence, or skip the song. A track shorter or longer than the master gets a warning.

Listen before Traktor

The download includes StemPlayer: open a finished file and mute or solo each stem, to check the result before it goes into your Traktor collection.

How it works

Four steps, no installation.

  1. Download and unzipGet StemPacker-<version>.zip, unzip it anywhere and start StemPacker.exe. The guide StemPacker-User-Guide.pdf is in the same folder.
  2. Set folders and patternsPick a preset or type your own patterns, then choose the folders (or drop a folder onto the window).
  3. Find songsThe list shows every song, how many files were found and what is missing.
  4. Pack allEach song becomes <song>.stem.mp4 next to the master or in a folder of your choice. Load them into Traktor Pro 4.

Check the result with StemPlayer

StemPlayer is included in the download. It plays all four stems of a finished file in sync, with mute, solo and volume per stem, and shows them with the names and colours you set.

Elospeed StemPlayer
StemPlayer with a packed file: four stems Front, LFE, Center and Rear in their colours, each with mute and solo buttons and a volume slider

Part of the StemMaker family

Elospeed StemMaker separates your own music into stems with AI and packs them as Traktor stem files. StemPacker is for the other case: you already have the stems and only need the stem file.

Questions and answers

Is StemPacker really free?

Yes. StemPacker is open source under the MIT licence. There are no ads, no account and no paid version.

Does it separate music into stems?

No. StemPacker does not use AI. It packs files you already have. To separate a finished song into stems, use StemMaker.

Does it change my files?

No. Your master and stem files are only read. StemPacker writes new .stem.mp4 files. As with any new tool, please try it with copies of a few songs first.

Which files can it read?

WAV, FLAC, AIFF, MP3, M4A, OGG, Opus, W64 and WavPack. Mono files (for example LFE or a center channel) are played on both sides.

My stem file does not load into a Traktor track deck. Why?

That is how Traktor works: stem files only load into stem decks, also the ones made with Native Instruments' own Stem Creator. Switch the deck to a stem deck and load the file again.

A song shows “missing”. What now?

The list names the file it looked for, for example Stem 2 “Hello (B)”, and a similarly named file if it finds one (other spaces, punctuation or upper and lower case). Rename the file or adjust the pattern, then click “Find songs” again.

Can it read DVDs or cut .cue files?

No, and that is on purpose. Extract the audio with the tools you already use, then let StemPacker pack the files.

Windows shows “Windows protected your PC”. Is that a problem?

StemPacker is not digitally signed, because signing certificates cost money every year. Click “More info” and then “Run anyway”. The full source code is on GitHub, and you can check the download on VirusTotal or build it yourself.

Where can I ask questions or suggest ideas?

In the GitHub Discussions of StemMaker. Reading works without an account, writing needs a free GitHub account.

Ready to pack your stems?

Download the ZIP, try the Example folder, then your own songs.

⬇ Download StemPacker Read the guide

StemPacker is a one-person hobby project, free for good. If it saves you some time, you can buy me a coffee on Ko-fi ☕ or simply give it a star on GitHub. Both are entirely optional.