Service explainers
What is audio annotation and how does it work?
Updated 2026-08-01 · 4 min read
Short answer
Labelling of existing audio: speaker diarisation, emotion, intent, events, language identification and segment-level quality tagging, against your label schema. In practice the work runs as schema definition and edge-case documentation, then annotator training and gold-set calibration, then production annotation with gold items seeded in, and you receive labelled data in your schema, gold set and calibration results. Scoped per label complexity; simple diarisation runs at roughly 3-5x real time.
Key takeaways
- Gold items are seeded throughout production so drift is caught during the run, not at delivery.
- Typical buyers: Diarisation, Emotion AI, Intent classification.
- Recruitment approach: Annotators are native speakers with domain briefing, not generic crowd workers.
What the service covers
Labelling of existing audio: speaker diarisation, emotion, intent, events, language identification and segment-level quality tagging, against your label schema.
- Labelled data in your schema
- Gold set and calibration results
- Per-label agreement statistics
- Edge-case log
Technical specification
These are defaults, not limits. Where your pipeline requires different values, they replace ours in the statement of work rather than being converted after delivery.
| Parameter | Standard |
|---|---|
| Label types | Diarisation, emotion, intent, events, language ID, quality |
| Granularity | Segment, utterance, or frame-level boundaries |
| Schema | Yours, or authored with you before work starts |
| Agreement | Multi-annotator overlap on a defined percentage |
| Tooling | Client tooling supported; otherwise our annotation workflow |
How the work runs
- Schema definition and edge-case documentation
- Annotator training and gold-set calibration
- Production annotation with gold items seeded in
- Adjudication of disagreements by a senior reviewer
- Delivery with per-label agreement statistics
Quality control and acceptance
Gold items are seeded throughout production so drift is caught during the run, not at delivery.
Failures are remedied by re-collection rather than by editing delivered files, because repaired audio carries artefacts that survive into the trained model.
Who this is for
Recruitment for this service works as follows. Annotators are native speakers with domain briefing, not generic crowd workers.
- Diarisation
- Emotion AI
- Intent classification
- Data cleaning
Timelines
Scoped per label complexity; simple diarisation runs at roughly 3-5x real time.
Multi-language programmes run in parallel rather than in sequence, so a five-language scope does not take five times as long.
Frequently asked questions
What is included in audio annotation?
Labelled data in your schema, Gold set and calibration results, Per-label agreement statistics, delivered against a written specification with acceptance criteria attached.
How long does audio annotation take?
Scoped per label complexity; simple diarisation runs at roughly 3-5x real time.
How is quality measured?
Gold items are seeded throughout production so drift is caught during the run, not at delivery.
Which languages are supported?
Fifteen Indian languages plus Indian English, including Hindi, Marathi, Tamil, Telugu, Kannada.
Related reading
Turn this into a dataset specification
Tell us the languages, speaker count and minutes. You get a written scope, a protocol and a fixed price within one working day.