harmony 鸿蒙Audio Input Device Management

2023-06-24
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Audio Input Device Management

If a device is connected to multiple audio input devices, you can use AudioRoutingManager to specify an audio input device to record audio. For details about the API reference, see AudioRoutingManager.

Creating an AudioRoutingManager Instance

Before using AudioRoutingManager to manage audio devices, import the audio module and create an AudioManager instance.

import audio from '@ohos.multimedia.audio'; // Import the audio module.

import { BusinessError } from '@ohos.base'; // Import BusinessError.

let audioManager = audio.getAudioManager(); // Create an AudioManager instance.

let audioRoutingManager = audioManager.getRoutingManager(); // Call an API of AudioManager to create an AudioRoutingManager instance.

Supported Audio Input Device Types

The table below lists the supported audio input devices.

Name	Value	Description
WIRED_HEADSET	3	Wired headset with a microphone.
BLUETOOTH_SCO	7	Bluetooth device using Synchronous Connection Oriented (SCO) links.
MIC	15	Microphone.
USB_HEADSET	22	USB Type-C headset.

Obtaining Input Device Information

Use getDevices() to obtain information about all the input devices.

audioRoutingManager.getDevices(audio.DeviceFlag.INPUT_DEVICES_FLAG).then((data: audio.AudioDeviceDescriptors) => {
  console.info('Promise returned to indicate that the device list is obtained.');
});

Listening for Device Connection State Changes

Set a listener to listen for changes of the device connection state. When a device is connected or disconnected, a callback is triggered.

// Listen for connection state changes of audio devices.
audioRoutingManager.on('deviceChange', audio.DeviceFlag.INPUT_DEVICES_FLAG, (deviceChanged: audio.DeviceChangeAction) => {
  console.info('device change type: ' + deviceChanged.type); // Device connection state change. The value 0 means that the device is connected and 1 means that the device is disconnected.
  console.info('device descriptor size : ' + deviceChanged.deviceDescriptors.length);
  console.info('device change descriptor: ' + deviceChanged.deviceDescriptors[0].deviceRole); // Device role.
  console.info('device change descriptor: ' + deviceChanged.deviceDescriptors[0].deviceType); // Device type.
});

// Cancel the listener for the connection state changes of audio devices.
audioRoutingManager.off('deviceChange', (deviceChanged: audio.DeviceChangeAction) => {
  console.info('Should be no callback.');
});

Selecting an Audio Input Device (for System Applications only)

Currently, only one input device can be selected, and the device ID is used as the unique identifier. For details about audio device descriptors, see AudioDeviceDescriptors.

NOTE

The user can connect to a group of audio devices (for example, a pair of Bluetooth headsets), but the system treats them as one device (a group of devices that share the same device ID).

import audio from '@ohos.multimedia.audio';
let inputAudioDeviceDescriptor: audio.AudioDeviceDescriptors = [{
    deviceRole : audio.DeviceRole.INPUT_DEVICE,
    deviceType : audio.DeviceType.EARPIECE,
    id : 1,
    name : "",
    address : "",
    sampleRates : [44100],
    channelCounts : [2],
    channelMasks : [0],
    networkId : audio.LOCAL_NETWORK_ID,
    interruptGroupId : 1,
    volumeGroupId : 1,
    displayName : ""
}];

async function getRoutingManager() {
    audioRoutingManager.selectInputDevice(inputAudioDeviceDescriptor).then(() => {
      console.info('Invoke selectInputDevice succeeded.');
    }).catch((err: BusinessError) => {
      console.error(`Invoke selectInputDevice failed, code is ${err.code}, message is ${err.message}`);
    });
}