NIM SDK allows users to make high-definition voice recordings and playbacks for processing audio messages.

Audio recording

NIM SDK provides the AudioService class for audio recording.

Prerequisites

The microphone permission has been granted.

Implementation

1. Register the onAudioRecordStatus event stream to track changes of the audio recording status. The recordState enumeration in the RecordInfo of the callback defines the recording states.

   Field	type	Description
   READY	Enum type	The recorder is ready. The interface is used to close local audio and video playback before recording. The state is optional (not supported on Windows).
   START	Enum type	Start recording
   REACHED_MAX	Enum type	The audio duration reached the specified maximum recording time (not supported on Windows)
   SUCCESS	Enum type	Recording is completed successfully
   FAIL	Enum type	An error occurs while recording (the parameter is not supported on Windows)
   CANCEL	Enum type	The recording is canceled.

   /// Listen to the recording event
   NimCore.instance.audioService.onAudioRecordStatus.listen((RecordInfo recordInfo) {
   
           });
   
   

2. Start recording by calling the startRecord method.

   Parameter	Type	Description
   recordType	AudioOutputFormat	The type of a recording file. AAC or AMR
   maxDuration	int	The maximum duration for one recording. If the maximum duration is reached, recording will stop automatically, 120 seconds by default.

/// Start recording. If the callsucceeds, the `READY` and `START`callback will be triggered.
/// The maximum duration for onerecording. If the maximum duration isreached, recording will stopautomatically. 120 seconds by default.
NimCore.instanceaudioServicestartRecor(AudioOutputFormat.AAC1000);

3. (Optional) Call the following methods as needed.

   Method	Return value type	Description
   getAmplitude	int	Get the maximum amplitude of the current recording, and update the data every 40ms. The method is not supported on Windows
   isAudioRecording	bool	Whether recording is in progress. The method is not supported on Windows.
   cancelRecord	bool	Cancel recording

   `getAmplitude`

   /// Get the maximum amplitude of the current recording, and update the data every 40ms.
   NimCore.instance.audioService.getAmplitude();
   
   

   `isAudioRecording`

   /// Whether recording is in progress. 
   NimCore.instance.audioService.isAudioRecording();
   

   `cancelRecord`

   NimCore.instance.audioService.cancelRecord();
   

4. Stop recording by calling the stopRecord method.

   // Stop recording
   NimCore.instance.audioService.stopAudioRecord();
   

Speech-to-text

NIM SDK allows you to convert audio files into text.

How it works:

• Record an audio file (up to 60 seconds).
• Upload the audio file to the cloud storage server and return a URL.
• Pass the URL and related parameters in the speech-to-text interface, and return the converted text.

Prerequisites

To activate the speech-to-text feature, contact the sales manager using the WhatsApp provided on the homepage of CommsEase website

Implementation

Convert speech to text by calling the voiceToText method in the messageService class.

var result = await NimCore.instance.messageService
            .voiceToText(message);