Express server used to launch ffmpeg, transcode stream from peerflix and serve it to HTML5 video tag

app.js

var express = require('express'),
    http = require('http'),
    path = require('path'),
    child_process = require("child_process");

var app = express();

// Server settings
app.set('port', process.env.PORT || 9999);
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(express.errorHandler());

// Serve the video
app.get('/',function(req,res){
    // Write header
    res.writeHead(200, {
      'Content-Type': 'video/webm'
    });

    // Start ffmpeg
    var ffmpeg = child_process.spawn("./ffmpeg", [
        // Real time mode
        // "-re",

        // Source
        "-i", "http://localhost:8888",

        // Map multiple streams
        "-map", "0:0", "-map", "0:1", "-map", "0:1",

        // Some optimizations
        // "-preset","ultrafast",
        // "-tune","zerolatency",

        // Motion algorithms off
        // "-me_method","zero",
        // "-flags2","fast",

        // Quantization
        // "-qmin","5",
        // "-qmax","5",

        // Video: VP8 encoding
        "-c:v","libvpx",
        // quality
        "-crf","40",
        // target bit rate
        "-b:v","4M",

        // Audio: Vorbis  encoding
        "-c:a","libvorbis",
        // target bit rate
        "-b:a","256K",

        // Subtitles: copy
        "-c:s","copy",

        // File format
        "-f","webm",

        // Output to STDOUT
        "-"
    ]);

    // Pipe the video output to the client response
    ffmpeg.stdout.pipe(res);

    // Kill the subprocesses when client disconnects
    res.on("close", function(){
        ffmpeg.kill();
    })
});

// Start server
http.createServer(app).listen(app.get('port'), function(){
    console.log('Open http://localhost:' + app.get('port')+' to view the video from peerflix');
});

Hey,
So i am new to ffmpeg, so trying to fetch mp4 video from s3 url and send to client, but its now working some how, could you hep me on it.