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Versions, cutdowns and stems: what libraries ask for

A production music track rarely travels alone. Here are the usual versions, how long they are, and how to name the files so they stay together.

By , a composer with 300+ tracks on audio stock and 12 years in production. Updated 4 October 2026. 2 min read.

In short. Libraries often ask for the full mix, cutdowns of 60, 30 and 15 seconds, a loop, a stinger, an underscore without the melody, and stems. What each library wants differs, so ask first. Start every file name with the track's number, and keep a list of the versions in your catalog.

The usual versions

Version Length What it is
Full mix The whole track The main version
60, 30, 15 seconds Exactly that Edits for TV, radio and online ads, with a real ending
Loop Often under 30 seconds A part that repeats without a seam
Stinger A few seconds The end of the track: a hit and a ring out
Underscore The whole track The full mix without the lead melody, to sit under a voice
Alt mixes The whole track For example, without drums, or without vocals
Stems The whole track Separate files for drums, bass, keys and so on

Lengths of 60, 30 and 15 seconds match the usual lengths of ad spots. An editor drops them in without cutting.

Ask before you render

Stock sites, music libraries and trailer libraries ask for different things. One wants only the full mix and a short edit. Another wants five edits, an underscore and stems in groups. Ask what the library wants before you render, and keep their list.

Make the edits sound finished. A 30-second edit should start and end like music, not like a fade cut out of the middle.

Name the files so they stay together

Start every file with the track's number. Then the title. Then the version.

023_Harbour_Lights_Full.wav
023_Harbour_Lights_60.wav
023_Harbour_Lights_30.wav
023_Harbour_Lights_Loop.wav
023_Harbour_Lights_Underscore.wav
023_Harbour_Lights_Stems/023_Harbour_Lights_Stem_Drums.wav

The number keeps all versions of a track side by side in any folder. It also survives a new title: a library may retitle the track, but your number stays.

Give each track its own folder. The folder is the track, the files in it are its versions.

Codes for versions

An ISRC names one recording. A cutdown that differs from the full mix by more than 10 seconds is a different recording, so if you register an ISRC for it, it needs its own. The composition stays the same, so the ISWC does not change. See ISRC, ISWC and UPC.

Keep a list in your catalog

For each track, write down which versions exist and how long they are, and whether you have stems. When a library asks "do you have a 30 and stems for track 23?", you answer from the catalog, not by opening folders.

Sources