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POST
Audio Understand
Audio understanding is retired. As of 2026-10-08 no model is served on this endpoint: gemini-3-flash-audio, its only model, had no customer request in the preceding 90 days. The endpoint still exists; a request returns 404 model_not_found, and nothing is charged. The audio-understand alias was removed with it. For speech-to-text, /v1/audio/transcriptions is live. This page is no longer in the docs navigation; it records how the endpoint behaved.
Synchronous endpoint for audio understanding beyond transcription. Upload a clip, ask a question — get back a natural-language answer that captures the parts a transcript loses: tone, mood, music style, ambient SFX, speaker emotion, language.

When to use this vs transcribe

A good rule of thumb: if the answer can be reconstructed from transcript text, use transcribe. If it depends on how something sounds, this endpoint was the one.

Request

multipart/form-data upload.
file
required
Audio file. Supports mp3, wav, m4a, ogg, webm, flac. Max 25 MB inline (~30 minutes of mono 16kHz mp3).
string
required
Free-form text question about the audio, up to 4,000 characters. Be specific about what you want — “What is the mood?” is fine, but “Describe the music style, BPM, and any background SFX” gets more useful answers.
string
default:"gemini-3-flash-audio"
gemini-3-flash-audio, retired 2026-10-08. The audio-understand alias was removed the same day.
number
Deprecated and ignored. Still accepted so existing clients keep working; billing comes from the audio itself (see Pricing).

Response

200 OK with the answer text and a Kyma billing block.
string
The model’s answer to your question.
string
The Kyma model SKU that served the request.
string
upstream_usage (billed from the input the model consumed: your audio and your question) or file_bound (the model reported no usage, so the file’s own length bound was billed).
number
Final cost charged for this request.

Pricing

Nothing is charged: no model is served. While gemini-3-flash-audio was served it cost $0.002592 a minute, billed per minute and rounded up, on the length of the audio plus your question.

Errors

Examples

Mood and music brief for a video clip

Speaker emotion check

See also

  • Audio Transcriptions - speech-to-text
  • Audio models - the audio models served today
  • watch-cli - open-source CLI that pairs this endpoint with transcribe to give agents full audio understanding from any social video URL