node-demux

Node-Demux is a node.js package that decodes video files into raw frames in real-time. This is useful for creating a video player.

Prerequisites

FFMpeg (for developers)

• Windows
  • Download FFMpeg (Shared and Dev - 64bit)
  • Use 7-zip to extract downloads
  • Create folder 'C:\Dev' if it does not already exist
  • Move extracted FFMpeg Shared folder to 'C:\Dev\ffmpeg-win64-shared'
  • Move extracted FFMpeg Dev folder to 'C:\Dev\ffmpeg-win64-dev'
  • Add 'C:\Dev\ffmpeg-win64-shared\bin' to your system Path variable
• Mac OS X
  • brew install ffmpeg --with-libvpx --with-libvorbis --with-ffplay
• Linux
  • Install FFMpeg and FFMpeg-Dev from your package manager (may need at add repository prior to install)

Install

• npm install node-demux
  • Note: Windows users may need option to specify compiler --msvc_version=2013

Usage

declare new demuxer: var video = new demux();

Method	Use
video.load(filename, options)	loads video from file (filename is path or url to desired file, options is an optional object)
video.play()	starts demuxing video (callback for 'start' when it begins and 'frame' on each new decoded frame
video.pause(callback)	pauses demuxing (callback is called once video successfully pauses decoding
video.stop(callback)	stops demuxing (same as pause, but also seeks video back to start)
video.seek(timestamp, callback)	seeks video to desired time in seconds (callback is called once video successfully finished seek)
video.nextFrame()	decodes next frame as soon as possible ('frame' message will be called)
video.on(message)	message is one of 'error', 'metadata', 'start', 'end', or 'frame'

Load Options

Option	Meaning
decodeFirstFrame	boolean flag: decodes one frame after load, seek, or stop
colorspace	string: desired frame colorspace ('yuv420p' or 'rgb24')

Example

var demux = require('node-demux');


var start;
var nframes;

var video = new demux();
video.on('error', function(err) {
    console.log(err);
});
video.on('metadata', function(metadata) {
	nframes = 0;
    console.log(metadata);
});
video.on('start', function() {
    start = Date.now();
    console.log("start demuxing");
});
video.on('end', function() {
    var time = (Date.now() - start) / 1000;
    console.log("finished demuxing");
    console.log("  total time: " + time.toFixed(3) + "sec");
    console.log("  average frames per second: " + (nframes/time).toFixed(3) + "fps");
});
video.on('frame', function(frameIdx, data) {
    nframes++;
    console.log("received frame " + frameIdx + " (size: " + data.length + ")");
});
video.load("big-buck-bunny_trailer.mp4");
video.play();