Mic

Mic is the microphone, as a single object shared by the whole app. It captures audio, reports how loud the room is, and lists the inputs the system offers.

The recording itself is done by a driver: the Web Audio API in a browser, the native audio engine on a phone. Importing @micdrop/web or @micdrop/react-native installs the right one, so there is nothing to wire.

Usage Example

import { Mic } from '@micdrop/web'

// Ask for the microphone permission and start capturing
await Mic.start()

// Or record from a specific input
await Mic.start(deviceId)

// The level, in decibels between -Infinity and 0, about ten times a second
Mic.on('Volume', (volume: number) => {
  console.log('Current level:', volume)
})

// Stop capturing and release the microphone
await Mic.stop()

Starting and stopping a call already does this for you, see Start/Stop Call. Reach for Mic when you need the microphone on its own, for a level meter before the call begins for instance.

API Reference

Methods

start(deviceId?: string): Promise<void>

Asks for the microphone permission and starts capturing, from the given input or from the system one.

stop(): Promise<void>

Stops capturing and releases the microphone.

getDevices(): Promise<MicdropDevice[]>

Lists the inputs the system offers, each with an id, a label to show and its kind. A browser only reveals the labels once a stream is running.

setDriver(driver: MicDriver): void

Records with another library. See Using another audio library.

Properties

isStarted: boolean

Whether the microphone is capturing.

deviceId: string | undefined

The input in use, when the system reports one.

volume: number

The last level measured, in decibels between -Infinity and 0.

Events

Volume: [number]

The level of the captured audio, about ten times a second. It is the loudest frequency rather than the overall energy, which is what separates a voice from a room, see Voice Activity Detection.

Frames: [Float32Array, number]

A batch of mono samples in the -1..1 range, with their sample rate. This is the raw capture, before any chunking.

DeviceChange: []

The system gained or lost an audio device.

Error: [Error]

Capture failed.