node-av / lib / Device

Class: Device

Defined in: src/lib/device.ts:101

Low-level device enumeration and format detection.

Provides direct access to system capture devices (cameras, microphones) and platform-specific input format names for FFmpeg.

Direct mapping to platform-specific APIs:

• macOS: AVFoundation
• Linux: V4L2/ALSA
• Windows: DirectShow

Example

import { Device } from 'node-av/lib';

// List all capture devices
const devices = await Device.list();
for (const device of devices) {
  console.log(`[${device.type}] ${device.name}: ${device.description}`);
}

// Get platform-specific format names
console.log(`Video format: ${Device.getVideoFormat()}`);
console.log(`Audio format: ${Device.getAudioFormat()}`);
console.log(`Screen format: ${Device.getScreenFormat()}`);

See

DeviceInfo For device structure

Constructors

Constructor

new Device(): Device

Returns

Device

Methods

audioModes()

static audioModes(deviceName): Promise<AudioDeviceMode[]>

Defined in: src/lib/device.ts:262

Query supported audio capture modes for an audio device.

Returns supported sample rates, channel counts and sample formats for the specified device. Modes are sorted descending by sample rate, then by channel count.

Parameters

deviceName

string

Device name as returned by list() (e.g. uniqueID on macOS, hw:0 on Linux)

Returns

Promise<AudioDeviceMode[]>

Array of supported audio device modes

Example

const devices = await Device.list();
const mic = devices.find(d => d.type === 'audio');
if (mic) {
  const modes = await Device.audioModes(mic.name);
  console.log('Supported audio modes:', modes);
}

---

audioModesSync()

static audioModesSync(deviceName): AudioDeviceMode[]

Defined in: src/lib/device.ts:290

Query supported audio capture modes for an audio device synchronously.

Parameters

deviceName

string

Device name as returned by listSync()

Returns

AudioDeviceMode[]

Array of supported audio device modes

Example

const devices = Device.listSync();
const mic = devices.find(d => d.type === 'audio');
if (mic) {
  const modes = Device.audioModesSync(mic.name);
  console.log('Supported audio modes:', modes);
}

See

audioModes For async version

---

getAudioFormat()

static getAudioFormat(): string

Defined in: src/lib/device.ts:336

Get platform-specific audio input format name.

Returns

string

Format name for FFmpeg input

Platform	Format
macOS	avfoundation
Linux	alsa
Windows	dshow

Example

const format = Device.getAudioFormat(); // 'avfoundation' on macOS

---

getScreenFormat()

static getScreenFormat(): string

Defined in: src/lib/device.ts:356

Get platform-specific screen capture format name.

Returns

string

Format name for FFmpeg input

Platform	Format
macOS	avfoundation
Linux	x11grab
Windows	gdigrab

Example

const format = Device.getScreenFormat(); // 'avfoundation' on macOS

---

getVideoFormat()

static getVideoFormat(): string

Defined in: src/lib/device.ts:316

Get platform-specific video input format name.

Returns

string

Format name for FFmpeg input

Platform	Format
macOS	avfoundation
Linux	v4l2
Windows	dshow

Example

const format = Device.getVideoFormat();
// Use with Demuxer.open(deviceName, { format })

---

hasScreenCapturePermission()

static hasScreenCapturePermission(): boolean

Defined in: src/lib/device.ts:377

Check if the application has screen capture permission (macOS only).

Uses CGPreflightScreenCaptureAccess() on macOS 11+. Always returns true on Linux, Windows, and macOS < 11.

Returns

boolean

true if screen capture is permitted

Example

if (Device.hasScreenCapturePermission()) {
  console.log('Screen capture is permitted');
} else {
  console.log('Screen capture permission not granted');
}

---

list()

static list(): Promise<DeviceInfo[]>

Defined in: src/lib/device.ts:117

List all available capture devices.

Enumerates video and audio capture devices on the system. Uses platform-specific APIs for device discovery.

Returns

Promise<DeviceInfo[]>

Array of device information

Example

const devices = await Device.list();
const cameras = devices.filter(d => d.type === 'video');
const microphones = devices.filter(d => d.type === 'audio');

---

listSync()

static listSync(): DeviceInfo[]

Defined in: src/lib/device.ts:155

List all available capture devices synchronously.

Returns

DeviceInfo[]

Array of device information

Example

const devices = Device.listSync();

See

list For async version

---

modes()

static modes(deviceName): Promise<DeviceMode[]>

Defined in: src/lib/device.ts:201

Query supported capture modes for a video device.

Returns supported resolutions and frame rate ranges for the specified device. Modes are sorted descending by resolution (area), then by max frame rate.

Parameters

deviceName

string

Device name as returned by list() (e.g. uniqueID on macOS, /dev/video0 on Linux)

Returns

Promise<DeviceMode[]>

Array of supported device modes

Example

const devices = await Device.list();
const camera = devices.find(d => d.type === 'video');
if (camera) {
  const modes = await Device.modes(camera.name);
  console.log('Supported modes:', modes);
}

---

modesSync()

static modesSync(deviceName): DeviceMode[]

Defined in: src/lib/device.ts:231

Query supported capture modes for a video device synchronously.

Parameters

deviceName

string

Device name as returned by listSync()

Returns

DeviceMode[]

Array of supported device modes

Example

const devices = Device.listSync();
const camera = devices.find(d => d.type === 'video');
if (camera) {
  const modes = Device.modesSync(camera.name);
  console.log('Supported modes:', modes);
}

See

modes For async version

---

requestScreenCaptureAccess()

static requestScreenCaptureAccess(): boolean

Defined in: src/lib/device.ts:400

Request screen capture permission from the user (macOS only).

Uses CGRequestScreenCaptureAccess() on macOS 11+. This will trigger the system permission dialog if not already granted. Always returns true on Linux, Windows, and macOS < 11.

Returns

boolean

true if permission was already granted (does not wait for dialog)

Example

const granted = Device.requestScreenCaptureAccess();
if (granted) {
  console.log('Screen capture permission already granted');
} else {
  console.log('Screen capture permission dialog shown to user');
}