Nth Permutation Mathematics


    1.0.4 • Public • Published


    Capturing images from USB(UVC) webcam on linux machines.


    • node >= 4.x
    • video4linux2 headers
    • c and c++ compiler with -std=c11 and -std=c++14
      • gcc >= 4.9


    On linux machines:

    npm install v4l2camera


    var v4l2camera = require("v4l2camera");
    var cam = new v4l2camera.Camera("/dev/video0");
    if (cam.configGet().formatName !== "MJPG") {
      console.log("NOTICE: MJPG camera required");
    cam.capture(function (success) {
      var frame = cam.frameRaw();

    For more detail see: examples/*.js (required "pngjs" modules)


    Initializing and Configuration API

    • var cam = new v4l2camera.Camera(device)
      • device: e.g. "/dev/video0"
    • cam.formats: Array of available frame formats
    • var format = cam.formats[n]
      • format.formatName: Name of pixel format. e.g. "YUYV", "MJPG"
      • format.format: ID number of pixel format
      • format.width: Frame width
      • format.height: Frame height
      • format.interval.numerator and format.interval.denominator : Capturing interval per numerator/denominator seconds (e.g. 30fps is 1/30)
    • cam.configSet(format) : Set capture width, height, interval per numerator/denominator sec if the members exist in the format object
    • cam.configGet() : Get a format object of current config

    Capturing API (control flow)

    • cam.start()
    • cam.stop(afterStoped)
      • call re-config(format) or re-start() in afterStoped() callback
    • cam.capture(afterCaptured): Do cache a current captured frame
      • use cam.frameRaw() in afterCaptured(true) callback

    Capturing API (frame access)

    • cam.frameRaw(): Get the cached raw frame as Uint8Array (YUYU frame is array of YUYV..., MJPG frame is single JPEG compressed data)
    • cam.toYUYV(): Get the cached frame as Uint8Array of pixels YUYVYUYV... (will be deprecated method)
    • cam.toRGB(): Get the cached frame as Uint8Array of pixels RGBRGB... (will be deprecated method)

    Capturing API (camera frame info)

    • cam.device: the device file name e.g. "/dev/video0"
    • cam.width: pixel width of the camera
    • cam.height: pixel height of the camera

    Control API

    • cam.controls: Array of the control information
    • cam.controlGet(id): Get int value of the control of the id (id is one of cam.controls[n].id)
    • cam.controlSet(id, value): Set int value of the control of the id
    • var control = cam.controls[n]: Control spec
      • control.id: Control id for controlGet and controlSet
      • control.name: Control name string
      • control.type: "int", "bool", "button", "menu" or other types
      • control.max, control.min, control.step: value should be min <= v and v <= max and (v - min) % step === 0
      • control.default: default value of the control
      • control.flags: Several bool flags of the controls
      • control.menu: Array of items. A control value is the index of the menu item when type is "menu".

    Build for Development

    On linux machines:

    cd myproject
    mkdir -p node_modules
    cd node_modules
    git clone https://github.com/bellbind/node-v4l2camera.git v4l2camera
    cd v4l2camera
    npm install
    cd ../..

    "build/Release/v4l2camera.node" is exist after the build.

    Tested Environments

    • Ubuntu wily armhf on BeagleBone Black with USB Buffalo BSW13K10H
    • Ubuntu wily amd64 on Acer Aspire One with its screen facecam
    • Travis-CI (build only): Build Status


    MIT and LGPL-3.0 dual


    npm i v4l2camera

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    (MIT OR LGPL-3.0)

    Last publish


    • bellbind