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# SFSpeechAudioBufferRecognitionRequest

A request to recognize speech from captured audio content, such as audio from the device’s microphone.

```
class SFSpeechAudioBufferRecognitionRequest
```

## Overview

Use an [`SFSpeechAudioBufferRecognitionRequest`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest) object to perform speech recognition on live audio, or on a set of existing audio buffers. For example, use this request object to route audio from a device’s microphone to the speech recognizer.

The request object contains no audio initially. As you capture audio, call [`append(_:)`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/append(_:)) or [`appendAudioSampleBuffer(_:)`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/appendAudioSampleBuffer(_:)) to add audio samples to the request object. The speech recognizer continuously analyzes the audio you appended, stopping only when you call the [`endAudio()`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/endAudio()) method. You must call [`endAudio()`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/endAudio()) explicitly to stop the speech recognition process.

For a complete example of how to use audio buffers with speech recognition, see [SpeakToMe: Using Speech Recognition with AVAudioEngine](https://developer.apple.com/library/archive/samplecode/SpeakToMe/Introduction/Intro.html#//apple_ref/doc/uid/TP40017110).

## Topics

### Appending Audio Buffers

[`append(_:)`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/append(_:))

Appends audio in the PCM format to the end of the recognition request.

[`appendAudioSampleBuffer(_:)`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/appendAudioSampleBuffer(_:))

Appends audio to the end of the recognition request.

[`endAudio()`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/endAudio())

Marks the end of audio input for the recognition request.

### Getting the Audio Format

[`nativeAudioFormat`](/documentation/Speech/SFSpeechAudioBufferRecognitionRequest/nativeAudioFormat)

The preferred audio format for optimal speech recognition.


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