node-v4l2camera

IMPORTANT NOTE: This is a fork of the original node-v4l2camera module. It exists only to fix bellbind/node-v4l2camera#30, which hasn't been fixed upstream yet. This fork will not receive any further updates, once the upstream repository has fixed the issue!

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

Requirements

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

Install

On linux machines:

npm install @joepie91/v4l2camera

• package details: https://npmjs.org/package/v4l2camera

Usage

var v4l2camera = require("v4l2camera");

var cam = new v4l2camera.Camera("/dev/video0");
if (cam.configGet().formatName !== "MJPG") {
  console.log("NOTICE: MJPG camera required");
  process.exit(1);
}
cam.start();
cam.capture(function (success) {
  var frame = cam.frameRaw();
  require("fs").createWriteStream("result.jpg").end(Buffer(frame));
  cam.stop();
});

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

API

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):

Licenses

MIT and LGPL-3.0 dual