Rocket.Chat.ReactNative/app/lib/constants/audio.ts

import { Audio, AudioMode, InterruptionModeAndroid, InterruptionModeIOS } from 'expo-av';
import { RecordingOptions } from 'expo-av/build/Audio';

export const RECORDING_EXTENSION = '.aac';
export const RECORDING_SETTINGS: RecordingOptions = {
	android: {
		// Settings related to audio encoding.
		extension: RECORDING_EXTENSION,
		outputFormat: Audio.RECORDING_OPTION_ANDROID_OUTPUT_FORMAT_AAC_ADTS,
		audioEncoder: Audio.RECORDING_OPTION_ANDROID_AUDIO_ENCODER_AAC,
		// Settings related to audio quality.
		sampleRate: Audio.RECORDING_OPTIONS_PRESET_LOW_QUALITY.android.sampleRate,
		numberOfChannels: Audio.RECORDING_OPTIONS_PRESET_LOW_QUALITY.android.numberOfChannels,
		bitRate: Audio.RECORDING_OPTIONS_PRESET_LOW_QUALITY.android.bitRate
	},
	ios: {
		// Settings related to audio encoding.
		extension: RECORDING_EXTENSION,
		audioQuality: Audio.RECORDING_OPTION_IOS_AUDIO_QUALITY_MEDIUM,
		outputFormat: Audio.RECORDING_OPTION_IOS_OUTPUT_FORMAT_MPEG4AAC,
		// Settings related to audio quality.
		sampleRate: Audio.RECORDING_OPTIONS_PRESET_LOW_QUALITY.ios.sampleRate,
		numberOfChannels: Audio.RECORDING_OPTIONS_PRESET_LOW_QUALITY.ios.numberOfChannels,
		bitRate: Audio.RECORDING_OPTIONS_PRESET_LOW_QUALITY.ios.bitRate
	},
	web: {},
	keepAudioActiveHint: true
};

export const RECORDING_MODE: AudioMode = {
	allowsRecordingIOS: true,
	playsInSilentModeIOS: true,
	staysActiveInBackground: true,
	shouldDuckAndroid: true,
	playThroughEarpieceAndroid: false,
	interruptionModeIOS: InterruptionModeIOS.DoNotMix,
	interruptionModeAndroid: InterruptionModeAndroid.DoNotMix
};

export const AUDIO_MODE: AudioMode = {
	allowsRecordingIOS: false,
	playsInSilentModeIOS: true,
	staysActiveInBackground: true,
	shouldDuckAndroid: true,
	playThroughEarpieceAndroid: false,
	interruptionModeIOS: InterruptionModeIOS.DoNotMix,
	interruptionModeAndroid: InterruptionModeAndroid.DoNotMix
};