node.js infrared audio to binary

infraredaudio2binary.js

var spawn = require('child_process').spawn,
    info = spawn('file', [ process.argv[2] ]);


var infos = [];

info.stdout.setEncoding('utf8');
info.stdout.on('data', function(buf) { infos.push(buf); });
info.stdout.on('end', function() {
    var x = infos.join(''),
        data = /:.*\s*\((.*)\).*\, ([0-9]*) bit.*\, [a-z]* ([0-9]*) Hz/.exec(x),
        finfo = {
            endian: data[1],
            bitRate: data[2],
            sampleRate: data[3]
        },
        readfn = "readUInt" + finfo.bitRate + (finfo.endian == 'little-endian'?"LE":"BE"),
        samples = [],
        sox = spawn('sox', [process.argv[2],'-t','raw','-']);
        sox.stdout.on('data', function(buf) {
            for (var k = 0; k < buf.length; k += finfo.bitRate / 8)
                samples.push(buf[readfn](k));
        });
        sox.stdout.on('end', function() {
            ret = processAudio(samples);

            var minLen = ret.reduce(function(m, x) { return Math.min(m, x.count); }, 96000);
            oneSamples = ret.filter(function(el) { return Math.round(el.count / minLen) == 1 });
            minLen = oneSamples.reduce(function(acc, e) { return acc + e.count }, 0) / oneSamples.length;
            ret = ret.map(function(el) { return {count: Math.round(el.count / minLen), state: el.state }; });
            
            ret.forEach(function(el) {
                for (var k = 0; k < Math.round(el.count); ++k)
                    process.stdout.write(""+el.state);
            });
            process.stdout.write("\n");
        });
});

function processAudio(s) {
    var ret = [], last = null;
    for (var k = 0; k < s.length; ++k) {
        var smp = s[k] / 65535;
        if (!last) last = { state: Math.round(smp), count: 0}
        var state = smp > 0.66 ? 1 
                  : smp < 0.33 ? 0
                  : last.state;
        if (last.state != state) { 
            if (last.count > 5) ret.push(last);
            last = {state: state, count:0}; 
        }
        last.count += 1;
    }
    return ret;
};

results

spion@lappy:~/Documents/node-ir-wav$ node irwav2bin.js 16c.wav 
000000000000000000001110100001100010001001101110111100010011111100001110000011101111101000001110000111011011110010111011100011001000101100111000111011101110000011111111111111111111111110111000100010100111101111101000111110111110000011101111111000001111000011101010001100011010100010001110110001110011111000101100101010000111101110111
spion@lappy:~/Documents/node-ir-wav$ node irwav2bin.js 17c.wav 
00000000000000000000111101110101010000011101110100011111110000000001111000111110010001001100110110110001001000011000010011011101110110010110111111111111111111111000000111111111111111110111101001100001000110000101000001101101110000000001110111000001110111100010011111010010010110010111110100100001110111110101000001100001110111011100000
spion@lappy:~/Documents/node-ir-wav$ node irwav2bin.js 18c.wav 
000000000000000000011100100000011101110100100011011111010011110000111111111111001101100111010101011101011111011000111100110001011000110001100111111111000010000110000000000000000000000011110010110110110010111000010000001010111111110000111000001110111111101110101110111011101010001011111110001111101110000010101011001000111111101111111
spion@lappy:~/Documents/node-ir-wav$ node irwav2bin.js 19c.wav 
00000000000000000000110100001001111100001000001100111111010111100001110000011111110101000111110110110101001100000101010111011000110101001100010111011101110111000111111111111111111111110111010101011000101100001111011100100111011101110111100011110000100000000101000100001100010001111111111101011100000101111110010011010111110111111101110
spion@lappy:~/Documents/node-ir-wav$ node irwav2bin.js 20c.wav 
0000001111111111111111111011110011101001001011110010000010010001000011101110111011101011011010011100110110101111101100111010000011101010100000111111111100001110111000000111111111111111111111110101000110010111110001011110010000000111100001111000011101110111011100010110010101110111100111011100111100010101110100100101110001110111111110001
spion@lappy:~/Documents/node-ir-wav$ node irwav2bin.js 21c.wav 
000000111111111111111110110000101011101100101111101011101010111011101110000111110110110010111110111100111010001011001010101001001100101110000010000011101110111011111111111111111111111110111001101010101101111111101000101001000011111110111011101110111011111110101000100011101001001011101111101000010011000000111110111111111110111011101110