Audio Analysis
Automatic detection of BPM, key, genre, mood, and instruments.
How It Works
When you add audio, Locker's own analyser listens to it and detects its musical properties. Analysis runs in the background on each version, so you can keep working while it processes. Once complete, the results appear on the version in the track's panel.
The analyser uses models trained on large music datasets. It examines tempo, harmonic content, timbre and spectral features to fill in the details. These results then power Locker's filters, search, and brief matching.
What Gets Detected
Every analysed version receives the following metadata:
- BPM (Tempo): Exact beats per minute, plus alternative readings at half and double tempo for ambiguous cases
- Musical Key: Key signature and mode (e.g., C major, F# minor), with a confidence score
- Genre: Multiple genre tags ranked by confidence, so you see the primary genre and close alternatives
- Mood: Emotional character of the track, also ranked by confidence
- Instruments: Detected instruments present in the audio, sorted by prominence
- Vocal/Instrumental: Whether the track contains vocals, useful for filtering sync-ready instrumentals
- Waveform: Visual representation of the audio for quick navigation
- Duration: Precise length in seconds
Very short clips (under about 30 seconds) may not get genre, mood or instruments, because there is not enough to listen to. Tempo and key still come through.
Re-Analysing
You can re-run analysis on any version. This is useful if you have replaced the audio file, if analysis failed previously, or if you want to refresh the results. On a computer, open the version's ··· menu and choose Analyze this version.
Re-analysis uses one analyser credit. To fill in many tracks at once, use the suggestion in Tasks that offers to let Locker fill in the recordings that are missing details, or ask Kii to analyse a set of tracks.
Version-Level Data
Analysis data belongs to the version, not the track. This matters because different versions of the same song can have different tempos, keys, or instrumentation. A home demo might be in a different key than the studio version. A remix might have a completely different BPM.
When you view a track in the library, the displayed BPM, key, and tags come from the Main version. Make a different version Main to change what shows in the track list.
Analyser Credits
Every new version is analysed when it arrives. Analyser credits cover re-analysis: each plan includes a monthly allocation, and one credit is used per version re-analysed. Unused credits roll over to the next month up to your plan's maximum balance, so quiet months build a buffer for busier ones.
If you run out of credits mid-month, you can wait for the next month or move to a plan with a higher allocation. You can check your current balance in Settings, under Plan and billing.