Audio understanding

Gemini can analyze and understand audio input, enabling use cases like the following:

  • Describe, summarize, or answer questions about audio content.
  • Provide a transcription of the audio.
  • Analyze specific segments of the audio.

This guide shows you how to use the Gemini API to generate a text response to audio input.

Input audio

You can provide audio data to Gemini in the following ways:

Upload an audio file

You can use the Files API to upload an audio file. Always use the Files API when the total request size (including the files, text prompt, system instructions, etc.) is larger than 20 MB.

The following code uploads an audio file and then uses the file in a call to generateContent.

Python

from google import genai

client = genai.Client(api_key="GOOGLE_API_KEY")

myfile = client.files.upload(file="path/to/sample.mp3")

response = client.models.generate_content(
    model="gemini-2.0-flash", contents=["Describe this audio clip", myfile]
)

print(response.text)

JavaScript

import {
  GoogleGenAI,
  createUserContent,
  createPartFromUri,
} from "@google/genai";

const ai = new GoogleGenAI({ apiKey: "GOOGLE_API_KEY" });

async function main() {
  const myfile = await ai.files.upload({
    file: "path/to/sample.mp3",
    config: { mimeType: "audio/mp3" },
  });

  const response = await ai.models.generateContent({
    model: "gemini-2.0-flash",
    contents: createUserContent([
      createPartFromUri(myfile.uri, myfile.mimeType),
      "Describe this audio clip",
    ]),
  });
  console.log(response.text);
}

await main();

Go

file, err := client.UploadFileFromPath(ctx, "path/to/sample.mp3", nil)
if err != nil {
    log.Fatal(err)
}
defer client.DeleteFile(ctx, file.Name)

model := client.GenerativeModel("gemini-2.0-flash")
resp, err := model.GenerateContent(ctx,
    genai.FileData{URI: file.URI},
    genai.Text("Describe this audio clip"))
if err != nil {
    log.Fatal(err)
}

printResponse(resp)

REST

AUDIO_PATH="path/to/sample.mp3"
MIME_TYPE=$(file -b --mime-type "${AUDIO_PATH}")
NUM_BYTES=$(wc -c < "${AUDIO_PATH}")
DISPLAY_NAME=AUDIO

tmp_header_file=upload-header.tmp

# Initial resumable request defining metadata.
# The upload url is in the response headers dump them to a file.
curl "https://generativelanguage.googleapis.com/upload/v1beta/files?key=${GOOGLE_API_KEY}" \
  -D upload-header.tmp \
  -H "X-Goog-Upload-Protocol: resumable" \
  -H "X-Goog-Upload-Command: start" \
  -H "X-Goog-Upload-Header-Content-Length: ${NUM_BYTES}" \
  -H "X-Goog-Upload-Header-Content-Type: ${MIME_TYPE}" \
  -H "Content-Type: application/json" \
  -d "{'file': {'display_name': '${DISPLAY_NAME}'}}" 2> /dev/null

upload_url=$(grep -i "x-goog-upload-url: " "${tmp_header_file}" | cut -d" " -f2 | tr -d "\r")
rm "${tmp_header_file}"

# Upload the actual bytes.
curl "${upload_url}" \
  -H "Content-Length: ${NUM_BYTES}" \
  -H "X-Goog-Upload-Offset: 0" \
  -H "X-Goog-Upload-Command: upload, finalize" \
  --data-binary "@${AUDIO_PATH}" 2> /dev/null > file_info.json

file_uri=$(jq ".file.uri" file_info.json)
echo file_uri=$file_uri

# Now generate content using that file
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key=$GOOGLE_API_KEY" \
    -H 'Content-Type: application/json' \
    -X POST \
    -d '{
      "contents": [{
        "parts":[
          {"text": "Describe this audio clip"},
          {"file_data":{"mime_type": "${MIME_TYPE}", "file_uri": '$file_uri'}}]
        }]
      }' 2> /dev/null > response.json

cat response.json
echo

jq ".candidates[].content.parts[].text" response.json

To learn more about working with media files, see Files API.

Pass audio data inline

Instead of uploading an audio file, you can pass inline audio data in the request to generateContent:

Python

from google.genai import types

with open('path/to/small-sample.mp3', 'rb') as f:
    audio_bytes = f.read()

response = client.models.generate_content(
  model='gemini-2.0-flash',
  contents=[
    'Describe this audio clip',
    types.Part.from_bytes(
      data=audio_bytes,
      mime_type='audio/mp3',
    )
  ]
)

print(response.text)

JavaScript

import { GoogleGenAI } from "@google/genai";
import * as fs from "node:fs";

const ai = new GoogleGenAI({ apiKey: "GOOGLE_API_KEY" });
const base64AudioFile = fs.readFileSync("path/to/small-sample.mp3", {
  encoding: "base64",
});

const contents = [
  { text: "Please summarize the audio." },
  {
    inlineData: {
      mimeType: "audio/mp3",
      data: base64AudioFile,
    },
  },
];

const response = await ai.models.generateContent({
  model: "gemini-2.0-flash",
  contents: contents,
});
console.log(response.text);

Go

// Initialize a Gemini model appropriate for your use case.
model := client.GenerativeModel("gemini-2.0-flash")

bytes, err := os.ReadFile("path/to/small-sample.mp3")
if err != nil {
  log.Fatal(err)
}

prompt := []genai.Part{
  genai.Blob{MIMEType: "audio/mp3", Data: bytes},
  genai.Text("Please summarize the audio."),
}

// Generate content using the prompt.
resp, err := model.GenerateContent(ctx, prompt...)
if err != nil {
  log.Fatal(err)
}

// Handle the response of generated text
for _, c := range resp.Candidates {
  if c.Content != nil {
    fmt.Println(*c.Content)
  }
}

A few things to keep in mind about inline audio data:

  • The maximum request size is 20 MB, which includes text prompts, system instructions, and files provided inline. If your file's size will make the total request size exceed 20 MB, then use the Files API to upload an audio file for use in the request.
  • If you're using an audio sample multiple times, it's more efficient to upload an audio file.

Get a transcript

To get a transcript of audio data, just ask for it in the prompt:

Python

myfile = client.files.upload(file='path/to/sample.mp3')
prompt = 'Generate a transcript of the speech.'

response = client.models.generate_content(
  model='gemini-2.0-flash',
  contents=[prompt, myfile]
)

print(response.text)

JavaScript

import {
  GoogleGenAI,
  createUserContent,
  createPartFromUri,
} from "@google/genai";

const ai = new GoogleGenAI({ apiKey: "GOOGLE_API_KEY" });
const myfile = await ai.files.upload({
  file: "path/to/sample.mp3",
  config: { mimeType: "audio/mpeg" },
});

const result = await ai.models.generateContent({
  model: "gemini-2.0-flash",
  contents: createUserContent([
    createPartFromUri(myfile.uri, myfile.mimeType),
    "Generate a transcript of the speech.",
  ]),
});
console.log("result.text=", result.text);

Go

// Initialize a Gemini model appropriate for your use case.
model := client.GenerativeModel("gemini-2.0-flash")

// Create a prompt using text and the URI reference for the uploaded file.
prompt := []genai.Part{
  genai.FileData{URI: sampleAudio.URI},
  genai.Text("Generate a transcript of the speech."),
}

// Generate content using the prompt.
resp, err := model.GenerateContent(ctx, prompt...)
if err != nil {
  log.Fatal(err)
}

// Handle the response of generated text
for _, c := range resp.Candidates {
  if c.Content != nil {
    fmt.Println(*c.Content)
  }
}

Refer to timestamps

You can refer to specific sections of an audio file using timestamps of the form MM:SS. For example, the following prompt requests a transcript that

  • Starts at 2 minutes 30 seconds from the beginning of the file.

  • Ends at 3 minutes 29 seconds from the beginning of the file.

Python

# Create a prompt containing timestamps.
prompt = "Provide a transcript of the speech from 02:30 to 03:29."

JavaScript

// Create a prompt containing timestamps.
const prompt = "Provide a transcript of the speech from 02:30 to 03:29."

Go

// Create a prompt containing timestamps.
prompt := []genai.Part{
    genai.FileData{URI: sampleAudio.URI},
    genai.Text("Provide a transcript of the speech from 02:30 to 03:29."),
}

Count tokens

Call the countTokens method to get a count of the number of tokens in an audio file. For example:

Python

response = client.models.count_tokens(
  model='gemini-2.0-flash',
  contents=[myfile]
)

print(response)

JavaScript

import {
  GoogleGenAI,
  createUserContent,
  createPartFromUri,
} from "@google/genai";

const ai = new GoogleGenAI({ apiKey: "GOOGLE_API_KEY" });
const myfile = await ai.files.upload({
  file: "path/to/sample.mp3",
  config: { mimeType: "audio/mpeg" },
});

const countTokensResponse = await ai.models.countTokens({
  model: "gemini-2.0-flash",
  contents: createUserContent([
    createPartFromUri(myfile.uri, myfile.mimeType),
  ]),
});
console.log(countTokensResponse.totalTokens);

Go

tokens, err := model.CountTokens(ctx, genai.FileData{URI: sampleAudio.URI})
if err != nil {
    log.Fatal(err)
}
fmt.Printf("File %s is %d tokens", sampleAudio.DisplayName, tokens.TotalTokens)

Supported audio formats

Gemini supports the following audio format MIME types:

  • WAV - audio/wav
  • MP3 - audio/mp3
  • AIFF - audio/aiff
  • AAC - audio/aac
  • OGG Vorbis - audio/ogg
  • FLAC - audio/flac

Technical details about audio

  • Gemini represents each second of audio as 32 tokens; for example, one minute of audio is represented as 1,920 tokens.
  • Gemini can only infer responses to English-language speech.
  • Gemini can "understand" non-speech components, such as birdsong or sirens.
  • The maximum supported length of audio data in a single prompt is 9.5 hours. Gemini doesn't limit the number of audio files in a single prompt; however, the total combined length of all audio files in a single prompt can't exceed 9.5 hours.
  • Gemini downsamples audio files to a 16 Kbps data resolution.
  • If the audio source contains multiple channels, Gemini combines those channels into a single channel.

What's next

This guide shows how to generate text in response to audio data. To learn more, see the following resources:

  • File prompting strategies: The Gemini API supports prompting with text, image, audio, and video data, also known as multimodal prompting.
  • System instructions: System instructions let you steer the behavior of the model based on your specific needs and use cases.
  • Safety guidance: Sometimes generative AI models produce unexpected outputs, such as outputs that are inaccurate, biased, or offensive. Post-processing and human evaluation are essential to limit the risk of harm from such outputs.