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();