diff --git a/.gitignore b/.gitignore
index 3c3629e..f06235c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 node_modules
+dist
diff --git a/README.md b/README.md
index fb5517c..09ddfa3 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,14 @@ ModPlayer JS makes use of the following piece of software:
 
 I also heavily used [MilkyTracker](https://milkytracker.titandemo.org/) and [webaudio-mod-player](https://mod.haxor.fi/) - which plays lot of module formats with high fidelity - to track down some timing bugs.
 
+# Building modplayer-js
+
+modplayer-js only needs a webserver, which can be installed by typing `npm install` and then `http-server`.
+
+If you want to use modplayer-js on an Xbox One, you'll also need to type `npm run build`: this will generate an ES5 version of the `mod-processor.js` file.
+
+This is because for some unknown reason, on Xbox One Edge, the audioworklet polyfill refuses to execute ES6 code.
+
 # Module background
 
 Modules are like MIDI files but with custom sound samples instead of builtin synth files.
diff --git a/js/main.js b/js/main.js
index 29424b6..90d8151 100644
--- a/js/main.js
+++ b/js/main.js
@@ -1,23 +1,23 @@
 var moduleList = [
     { file: 'https://api.modarchive.org/downloads.php?moduleid=91286#faggots_universe.mod', author: 'Deelite' },
-    { file: 'https://api.modarchive.org/downloads.php?moduleid=168739#neurodancer_-_quasar.mod', author: 'Neurodancer' },
-    { file: 'https://api.modarchive.org/downloads.php?moduleid=183672#tax_haven_dry_hump.mod', author: 'Curt Cool' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=182057#h0ffman_-_drop_the_panic.mod', author: 'h0ffman' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=168122#prodigy_-_downtown.mod', author: 'prodigy of oops' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=172266#hoffman_-_the_hunter.mod', author: 'h0ffman' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=65280#variations.mod', author: 'jogeir-liljedahl' },
-    { file: 'https://api.modarchive.org/downloads.php?moduleid=166686#wiklund_-_bonfire.mod', author: 'Wiklund' },
+    // { file: 'https://api.modarchive.org/downloads.php?moduleid=166686#wiklund_-_bonfire.mod', author: 'Wiklund' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=55058#pinball_illusions.mod', author: 'Olof Gustafsson' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=167668#vinnie_-_sweet_dreams.mod', author: 'vinnie/spaceballs' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=172271#subi-king_of_boggle.mod', author: 'Subi/DESiRE' },
-    { file: 'https://api.modarchive.org/downloads.php?moduleid=171416#bass-1107.mod', author: 'Noiseless (cm/ao)' },
+    // { file: 'https://api.modarchive.org/downloads.php?moduleid=171416#bass-1107.mod', author: 'Noiseless (cm/ao)' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=168110#punnik_-_drum_bass.mod', author: 'punnik' },
-    { file: 'https://api.modarchive.org/downloads.php?moduleid=171616#dan_-_childs_philozophy.mod', author: 'dan / picco' },
+    // { file: 'https://api.modarchive.org/downloads.php?moduleid=171616#dan_-_childs_philozophy.mod', author: 'dan / picco' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=119303#boesendorfer_p_s_s.mod', author: 'romeoknight' },
-    { file: 'https://api.modarchive.org/downloads.php?moduleid=170637#ghost_in_the_cli.mod', author: 'h0ffman' },
-    { file: 'https://api.modarchive.org/downloads.php?moduleid=158057#alf_-_no-mercy.mod', author: 'alf/vtl' },
+    // { file: 'https://api.modarchive.org/downloads.php?moduleid=170637#ghost_in_the_cli.mod', author: 'h0ffman' },
+    // { file: 'https://api.modarchive.org/downloads.php?moduleid=158057#alf_-_no-mercy.mod', author: 'alf/vtl' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=105709#trans_atlantic.mod', author: 'Lizardking'},
     { file: 'https://api.modarchive.org/downloads.php?moduleid=124303#agony_intro.mod', author: 'Tim Wright' },
+    { file: 'https://api.modarchive.org/downloads.php?moduleid=168739#neurodancer_-_quasar.mod', author: 'Neurodancer' },
+    { file: 'https://api.modarchive.org/downloads.php?moduleid=183672#tax_haven_dry_hump.mod', author: 'Curt Cool' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=98051#big_time_sensuality.mod', author: 'ISO/Axis Group' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=34568#CANNONFO.MOD', author: 'John Hare' },
     { file: 'https://api.modarchive.org/downloads.php?moduleid=68835#desert_strike.mod', author: 'Jason Whitley' },
diff --git a/js/mod-processor-es5.js b/js/mod-processor-es5.js
index fbe4c99..a8c366b 100644
--- a/js/mod-processor-es5.js
+++ b/js/mod-processor-es5.js
@@ -1,2 +1,2 @@
-var t=function(t,e,s){void 0===s&&(s=0);for(var i=new Uint8Array(t),o="",a=!1,n=0;!a;++n){var r=i[s+n];(a=0===r)||(o+=String.fromCharCode(r))}return o},e=function(t,e,s){return void 0===e&&(e=0),void 0===s&&(s=!1),new DataView(t).getUint16(e,s)},s=new Array(4);s[0]=new Float32Array(64);for(var i=0;i<s[0].length;++i)s[0][i]=64*Math.sin(2*Math.PI*(i/64));var o=function(s){function i(){s.call(this),this.port.onmessage=this.handleMessage.bind(this),this.patternOffset=1084,this.patternLength=1024}return s&&(i.__proto__=s),(i.prototype=Object.create(s&&s.prototype)).constructor=i,i.prototype.handleMessage=function(t){var e=this;switch(t.data.message){case"init":this.mixingRate=t.data.mixingRate,this.audioWorkletSupport=t.data.audioWorkletSupport;break;case"loadModule":this.prepareModule(t.data.buffer);break;case"setPlay":this.ready&&(this.playing=t.data.playing);break;case"reset":this.ready&&this.resetValues();break;case"setPlayingChannels":console.log(t.data.channels),t.data.channels.forEach(function(t,s){var i=e.channels[s];i&&(i.off=!t)});break;case"speedUp":console.log("speed up",t.data.speedUp),this.speedUp=t.data.speedUp,this.calcTickSpeed()}},i.prototype.postMessage=function(t){this.port.postMessage(t)},i.prototype.process=function(t,e,s){return this.ready&&this.playing?this.mix(e):this.emptyOutputBuffer(e),!0},i.prototype.emptyOutputBuffer=function(t){if(this.audioWorkletSupport)for(var e=t.length,s=t[0][0].length,i=0;i<e;++i)for(var o=0;o<s;++o)t[i][0][o]=0;else for(var a=t[0].length,n=t[0][0].length,r=0;r<a;++r)for(var p=0;p<n;++p)t[0][r][p]=0},i.prototype.init=function(){this.name="",this.samples=[],this.patterns=[],this.positions=[],this.songLength=0,this.channels||(this.channels=new Array(4)),this.maxSamples=0,this.bpm=125,this.speed=6,this.speedUp=1,this.position=0,this.pattern=0,this.row=0,this.samplesPerTick=0,this.filledSamples=0,this.ticks=0,this.newTick=!0,this.rowRepeat=0,this.rowJump=-1,this.skipPattern=!1,this.jumpPattern=-1,this.buffer=null,this.started=!1,this.ready=!1,this.playing=!1},i.prototype.resetValues=function(){this.started=!1,this.position=0,this.row=0,this.ticks=0,this.filledSamples=0,this.speed=6,this.newTick=!0,this.rowRepeat=0,this.rowJump=-1,this.skipPattern=!1,this.jumpPattern=-1,this.createChannels(),this.decodeRow()},i.prototype.createChannels=function(){for(var t=0;t<this.channels.length;++t){var e={sample:-1,samplePos:0,period:0,volume:64,slideTo:-1,slideSpeed:0,delay:0,vform:0,vdepth:0,vspeed:0,vpos:0,loopInitiated:!1,id:t};this.channels[t]?Object.assign(this.channels[t],e):this.channels[t]=e}},i.prototype.prepareModule=function(e){console.log("Decoding module data..."),this.ready=!1,this.init(),this.buffer=e,this.name=t(this.buffer,20),this.getInstruments(),this.getPatternData(),this.getSampleData(),this.calcTickSpeed(),this.createChannels(),this.resetValues(),this.ready=!0,this.postMessage({message:"moduleLoaded",data:{samples:this.samples,title:this.name,length:this.buffer.byteLength,positions:this.positions.length,patterns:this.patterns.length}})},i.prototype.detectMaxSamples=function(){var e=t(this.buffer,4,1080);this.maxSamples=e.match("M.K.")?31:15},i.prototype.calcTickSpeed=function(){this.samplesPerTick=60*this.mixingRate/(this.bpm*this.speedUp)/24},i.prototype.mix=function(t){for(var e=this.audioWorkletSupport&&t[0][0].length||t[0][0].length,s=0;s<e;++s){var i=0;this.audioWorkletSupport?(t[0][0][s]=0,t[1][0][s]=0,t[2][0][s]=0,t[3][0][s]=0):(t[0][0][s]=0,t[0][1][s]=0),this.tick();for(var o=0;o<this.channels.length;++o){var a=this.channels[o],n=this.audioWorkletSupport?t[o][0]:t[0][i];if(i^=1&o,this.newTick&&a.cmd&&this.executeEffect(a),!a.off&&a.period&&a.sample>-1&&!a.done&&this.ticks>=a.delay){var r=this.samples[a.sample];n[s]+=r.data[Math.floor(a.samplePos)]*a.volume/64,a.samplePos+=7093789.2/(2*a.period*this.mixingRate),a.done||(r.repeatLength||r.repeatStart?a.samplePos>=r.repeatStart+r.repeatLength&&(a.samplePos=r.repeatStart):a.samplePos>r.length&&(a.samplePos=0,a.done=!0))}}this.filledSamples++,this.newTick=!1}},i.prototype.tick=function(){this.filledSamples>this.samplesPerTick&&(this.newTick=!0,this.ticks++,this.filledSamples=0,this.ticks>this.speed-1&&(this.ticks=0,this.rowRepeat<=0&&this.row++,(this.row>63||this.skipPattern)&&(this.skipPattern=!1,this.jumpPattern>-1?(this.position=this.jumpPattern,this.jumpPattern=-1,this.getNextPattern()):this.getNextPattern(!0)),this.rowJump>-1&&(this.row=this.rowJump,this.rowJump=-1),this.row>63&&(this.row=0),this.decodeRow()))},i.prototype.getNextPattern=function(t){t&&this.position++,this.position>this.positions.length-1&&(console.log("Warning: last position reached, going back to 0"),this.position=0);for(var e=0;e<this.channels.length;++e)this.channels[e].loopInitiated=!1;this.pattern=this.positions[this.position],console.log("** position",this.position,"pattern:",this.pattern)},i.prototype.decodeRow=function(){this.started||(this.started=!0,this.getNextPattern());for(var t=new Uint8Array(this.patterns[this.pattern],16*this.row,16),e=0;e<this.channels.length;++e){var s=4*e,i=(15&t[s])<<8|t[1+s],o=(240&t[s]|t[2+s]>>4)-1,a=15&t[2+s],n=t[3+s],r=this.channels[e];r.delay=0,a?14===a?(r.cmd=224+(n>>4),r.data=15&n):(r.cmd=a,r.data=n):r.cmd=0,o>-1&&(3!==r.cmd&&5!==r.cmd&&(r.samplePos=0),r.done=!1,r.sample=o,r.volume=this.samples[o].volume),i&&(r.done=!1,3!==r.cmd&&5!==r.cmd?(r.period=i,r.samplePos=0):r.slideTo=i)}},i.prototype.executeEffect=function(t){try{a[t.cmd](this,t)}catch(e){console.warn("effect not implemented: "+t.cmd.toString(16).padStart(2,"0")+"/"+t.data.toString(16).padStart(2,"0"))}},i.prototype.getInstruments=function(){this.detectMaxSamples(),this.samples=new Array;for(var s=20,i=new Uint8Array(this.buffer),o=0;o<this.maxSamples;++o){var a={name:t(this.buffer,22,s),length:2*e(this.buffer,s+22),fintune:240&i[s+24],volume:i[s+25],repeatStart:2*e(this.buffer,s+26),repeatLength:2*e(this.buffer,s+28),data:null};2===a.repeatLength&&(a.repeatLength=0),a.repeatLength>a.length&&(a.repeatLength=0,a.repeatStart=0),this.samples.push(a),s+=30}},i.prototype.getPatternData=function(){var t=new Uint8Array(this.buffer,950);this.songLength=t[0];for(var e=2,s=0,i=0;i<this.songLength;++i){var o=t[e+i];this.positions.push(o),o>s&&(s=o)}e=this.patternOffset;for(var a=0;a<=s;++a)this.patterns.push(this.buffer.slice(e,e+this.patternLength)),e+=this.patternLength},i.prototype.getSampleData=function(){for(var t=this.patternOffset+this.patterns.length*this.patternLength,e=0;e<this.samples.length;++e){for(var s=this.samples[e].length,i=new Float32Array(s),o=new Int8Array(this.buffer,t,s),a=0;a<s;++a)i[a]=o[a]/128;this.samples[e].data=i,t+=s}},i.prototype.toggleLowPass=function(t){this.postMessage({message:"toggleLowPass",data:{activate:t}})},i}(AudioWorkletProcessor);registerProcessor("mod-processor",o);var a={1:function(t,e){t.ticks&&(e.period-=e.data,e.period<113&&(e.period=113))},2:function(t,e){t.ticks&&(e.period+=e.data,e.period>856&&(e.period=856))},3:function(t,e,s){t.ticks?e.slideTo&&t.ticks?e.period<e.slideTo?(e.period+=e.slideSpeed,e.period>e.slideTo&&(e.period=e.slideTo)):e.period>e.slideTo&&(e.period-=e.slideSpeed,e.period<e.slideTo&&(e.period=e.slideTo)):console.log("portamento + volume slide: keeping previous values"):!s&&e.data&&(e.slideSpeed=e.data)},4:function(t,e){if(!t.ticks){var i=15&e.data,o=(240&e.data)>>4;o&&i&&(e.vdepth=i,e.vspeed=o),e.vform>3&&(e.vpos=0)}e.period+=e.vdepth*s[3&e.vform][e.vpos]/63,e.vpos+=e.vspeed,e.vpos>63&&(e.vpos=e.vpos-64)},5:function(t,e){this[3](t,e),this[10](t,e)},6:function(t,e){this[4](t,e),this[10](t,e)},9:function(t,e){t.ticks||(e.samplePos=256*e.data)},10:function(t,e){if(t.ticks){var s=e.data>>4,i=15&e.data;i?s||(e.volume-=i):e.volume+=s,e.volume>63?e.volume=63:e.volume<0&&(e.volume=0)}},11:function(t,e){e.data>=0&&e.data<=t.patterns.length-1&&(t.skipPattern=!0,t.jumpPattern=e.data,t.rowJump=0)},12:function(t,e){t.ticks||(e.volume=e.data,e.volume>63&&(e.volume=63))},13:function(t,e){t.ticks||(t.rowJump=10*((240&e.data)>>4)+(15&e.data),t.skipPattern=!0)},224:function(t,e){t.ticks||(console.log("need to toggle lowPass",!!e.data),t.toggleLowPass(!!e.data))},228:function(t,e){},230:function(t,e){t.ticks||(0===e.data?e.loopInitiated?e.loops===e.loopCount&&(e.loopInitiated=!1):(e.loopInitiated=!0,e.loopStart=t.row,e.loopCount=0):e.loopInitiated&&(t.rowJump=e.loopStart,e.loopCount?e.loops++:(e.loopCount=e.data,e.loops=1)))},233:function(t,e){(t.ticks+1)%e.data||(console.log("retriggering note!",t.ticks+1),e.samplePos=0,e.done=!1)},234:function(t,e){t.ticks||(e.volume+=e.data,e.volume>63&&(e.volume=63))},235:function(t,e){t.ticks||(e.volume-=e.data,e.volume<0&&(e.volume=0))},237:function(t,e){t.ticks||(e.delay=e.data)},238:function(t,e){t.ticks||(t.rowRepeat?t.rowRepeat&&t.rowRepeat--:(t.rowRepeat=e.data,console.log("setting repeat to",t.rowRepeat)))},15:function(t,e){t.ticks||(e.data<32?t.speed=e.data:(t.bpm=e.data,t.calcTickSpeed()))}};
+var t=function(t,e,s){void 0===s&&(s=0);for(var i=new Uint8Array(t),o="",a=!1,n=0;!a;++n){var r=i[s+n];(a=0===r)||(o+=String.fromCharCode(r))}return o},e=function(t,e,s){return void 0===e&&(e=0),void 0===s&&(s=!1),new DataView(t).getUint16(e,s)},s=new Array(4);s[0]=new Float32Array(64);for(var i=0;i<s[0].length;++i)s[0][i]=64*Math.sin(2*Math.PI*(i/64));var o=function(s){function i(){s.call(this),this.port.onmessage=this.handleMessage.bind(this),this.patternLength=1024}return s&&(i.__proto__=s),(i.prototype=Object.create(s&&s.prototype)).constructor=i,i.prototype.handleMessage=function(t){var e=this;switch(t.data.message){case"init":this.mixingRate=t.data.mixingRate,this.audioWorkletSupport=t.data.audioWorkletSupport;break;case"loadModule":this.prepareModule(t.data.buffer);break;case"setPlay":this.ready&&(this.playing=t.data.playing);break;case"reset":this.ready&&this.resetValues();break;case"setPlayingChannels":console.log(t.data.channels),t.data.channels.forEach(function(t,s){var i=e.channels[s];i&&(i.off=!t)});break;case"speedUp":console.log("speed up",t.data.speedUp),this.speedUp=t.data.speedUp,this.calcTickSpeed()}},i.prototype.postMessage=function(t){this.port.postMessage(t)},i.prototype.process=function(t,e,s){return this.ready&&this.playing?this.mix(e):this.emptyOutputBuffer(e),!0},i.prototype.emptyOutputBuffer=function(t){if(this.audioWorkletSupport)for(var e=t.length,s=t[0][0].length,i=0;i<e;++i)for(var o=0;o<s;++o)t[i][0][o]=0;else for(var a=t[0].length,n=t[0][0].length,r=0;r<a;++r)for(var p=0;p<n;++p)t[0][r][p]=0},i.prototype.init=function(){this.name="",this.samples=[],this.patterns=[],this.positions=[],this.songLength=0,this.channels||(this.channels=new Array(4)),this.maxSamples=0,this.bpm=125,this.speed=6,this.speedUp=1,this.position=0,this.pattern=0,this.row=0,this.samplesPerTick=0,this.filledSamples=0,this.ticks=0,this.newTick=!0,this.rowRepeat=0,this.rowJump=-1,this.skipPattern=!1,this.jumpPattern=-1,this.buffer=null,this.started=!1,this.ready=!1,this.playing=!1},i.prototype.resetValues=function(){this.started=!1,this.position=0,this.row=0,this.ticks=0,this.filledSamples=0,this.speed=6,this.newTick=!0,this.rowRepeat=0,this.rowJump=-1,this.skipPattern=!1,this.jumpPattern=-1,this.createChannels(),this.decodeRow()},i.prototype.createChannels=function(){for(var t=0;t<this.channels.length;++t){var e={sample:-1,samplePos:0,period:0,volume:64,slideTo:-1,slideSpeed:0,delay:0,vform:0,vdepth:0,vspeed:0,vpos:0,loopInitiated:!1,id:t,cmd:0};this.channels[t]?Object.assign(this.channels[t],e):this.channels[t]=e}},i.prototype.prepareModule=function(e){console.log("Decoding module data..."),this.ready=!1,this.init(),this.buffer=e,this.name=t(this.buffer,20),this.getInstruments(),this.getPatternData(),this.getSampleData(),this.calcTickSpeed(),this.createChannels(),this.resetValues(),this.ready=!0,this.postMessage({message:"moduleLoaded",data:{samples:this.samples,title:this.name,length:this.buffer.byteLength,positions:this.positions.length,patterns:this.patterns.length}})},i.prototype.detectMaxSamples=function(){var e=t(this.buffer,4,1080);this.maxSamples=e.match("M.K.")?31:15,this.patternOffset=15===this.maxSamples?600:1084},i.prototype.calcTickSpeed=function(){this.samplesPerTick=60*this.mixingRate/(this.bpm*this.speedUp)/24},i.prototype.mix=function(t){for(var e=this.audioWorkletSupport&&t[0][0].length||t[0][0].length,s=0;s<e;++s){var i=0;this.audioWorkletSupport?(t[0][0][s]=0,t[1][0][s]=0,t[2][0][s]=0,t[3][0][s]=0):(t[0][0][s]=0,t[0][1][s]=0),this.tick();for(var o=0;o<this.channels.length;++o){var a=this.channels[o];i^=1&o;var n=this.audioWorkletSupport?t[o][0]:t[0][i];if(this.newTick&&a.cmd&&this.executeEffect(a),!a.off&&a.period&&a.sample>-1&&!a.done&&this.ticks>=a.delay){var r=this.samples[a.sample];n[s]+=r.data[Math.floor(a.samplePos)]*a.volume/64,a.samplePos+=7093789.2/(2*a.period*this.mixingRate),a.done||(r.repeatLength||r.repeatStart?a.samplePos>=r.repeatStart+r.repeatLength&&(a.samplePos=r.repeatStart):a.samplePos>r.length&&(a.samplePos=0,a.done=!0))}}this.filledSamples++,this.newTick=!1}},i.prototype.tick=function(){this.filledSamples>this.samplesPerTick&&(this.newTick=!0,this.ticks++,this.filledSamples=0,this.ticks>this.speed-1&&(this.ticks=0,this.rowRepeat<=0&&this.row++,(this.row>63||this.skipPattern)&&(this.skipPattern=!1,this.jumpPattern>-1?(this.position=this.jumpPattern,this.jumpPattern=-1,this.getNextPattern()):this.getNextPattern(!0)),this.rowJump>-1&&(this.row=this.rowJump,this.rowJump=-1),this.row>63&&(this.row=0),this.decodeRow()))},i.prototype.getNextPattern=function(t){t&&this.position++,this.position>this.positions.length-1&&(console.log("Warning: last position reached, going back to 0"),this.position=0);for(var e=0;e<this.channels.length;++e)this.channels[e].loopInitiated=!1;this.pattern=this.positions[this.position],console.log("** position",this.position,"pattern:",this.pattern)},i.prototype.decodeRow=function(){this.started||(this.started=!0,this.getNextPattern());for(var t=new Uint8Array(this.patterns[this.pattern],16*this.row,16),e=0;e<this.channels.length;++e){var s=4*e,i=(15&t[s])<<8|t[1+s],o=(240&t[s]|t[2+s]>>4)-1,a=15&t[2+s],n=t[3+s],r=this.channels[e];r.delay=0,a?14===a?(r.cmd=224+(n>>4),r.data=15&n):(r.cmd=a,r.data=n):r.cmd=0,o>-1&&(3!==r.cmd&&5!==r.cmd&&(r.samplePos=0),r.done=!1,r.sample=o,r.volume=this.samples[o].volume),i&&(r.done=!1,3!==r.cmd&&5!==r.cmd?(r.period=i,r.samplePos=0):r.slideTo=i)}},i.prototype.executeEffect=function(t){try{a[t.cmd](this,t)}catch(e){console.warn("effect not implemented: "+t.cmd.toString(16).padStart(2,"0")+"/"+t.data.toString(16).padStart(2,"0"))}},i.prototype.getInstruments=function(){this.detectMaxSamples(),this.samples=new Array;for(var s=20,i=new Uint8Array(this.buffer),o=0;o<this.maxSamples;++o){var a={name:t(this.buffer,22,s),length:2*e(this.buffer,s+22),fintune:240&i[s+24],volume:i[s+25],repeatStart:2*e(this.buffer,s+26),repeatLength:2*e(this.buffer,s+28),data:null};2===a.repeatLength&&(a.repeatLength=0,2===a.length&&(a.length=0)),a.repeatLength>a.length&&(a.repeatLength=0,a.repeatStart=0),this.samples.push(a),s+=30}},i.prototype.getPatternData=function(){var t=new Uint8Array(this.buffer,15===this.maxSamples?470:950);this.songLength=t[0];for(var e=2,s=0,i=0;i<this.songLength;++i){var o=t[e+i];this.positions.push(o),o>s&&(s=o)}e=this.patternOffset;for(var a=0;a<=s;++a)this.patterns.push(this.buffer.slice(e,e+this.patternLength)),e+=this.patternLength},i.prototype.getSampleData=function(){for(var t=this.patternOffset+this.patterns.length*this.patternLength,e=0;e<this.samples.length;++e){for(var s=this.samples[e].length,i=new Float32Array(s),o=t+s>this.buffer.byteLength?this.buffer.byteLength-t:s,a=new Int8Array(this.buffer,t,o),n=0;n<s;++n)i[n]=a[n]/128;this.samples[e].data=i,t+=o}},i.prototype.toggleLowPass=function(t){this.postMessage({message:"toggleLowPass",data:{activate:t}})},i}(AudioWorkletProcessor);registerProcessor("mod-processor",o);var a={1:function(t,e){t.ticks&&(e.period-=e.data,e.period<113&&(e.period=113))},2:function(t,e){t.ticks&&(e.period+=e.data,e.period>856&&(e.period=856))},3:function(t,e,s){t.ticks?e.slideTo&&t.ticks?e.period<e.slideTo?(e.period+=e.slideSpeed,e.period>e.slideTo&&(e.period=e.slideTo)):e.period>e.slideTo&&(e.period-=e.slideSpeed,e.period<e.slideTo&&(e.period=e.slideTo)):console.log("portamento + volume slide: keeping previous values"):!s&&e.data&&(e.slideSpeed=e.data)},4:function(t,e){if(!t.ticks){var i=15&e.data,o=(240&e.data)>>4;o&&i&&(e.vdepth=i,e.vspeed=o),e.vform>3&&(e.vpos=0)}e.period+=e.vdepth*s[3&e.vform][e.vpos]/63,e.vpos+=e.vspeed,e.vpos>63&&(e.vpos=e.vpos-64)},5:function(t,e){this[3](t,e),this[10](t,e)},6:function(t,e){this[4](t,e),this[10](t,e)},9:function(t,e){t.ticks||(e.samplePos=256*e.data)},10:function(t,e){if(t.ticks){var s=e.data>>4,i=15&e.data;i?s||(e.volume-=i):e.volume+=s,e.volume>63?e.volume=63:e.volume<0&&(e.volume=0)}},11:function(t,e){e.data>=0&&e.data<=t.patterns.length-1&&(t.skipPattern=!0,t.jumpPattern=e.data,t.rowJump=0)},12:function(t,e){t.ticks||(e.volume=e.data,e.volume>63&&(e.volume=63))},13:function(t,e){t.ticks||(t.rowJump=10*((240&e.data)>>4)+(15&e.data),t.skipPattern=!0)},224:function(t,e){t.ticks||(console.log("need to toggle lowPass",!!e.data),t.toggleLowPass(!!e.data))},228:function(t,e){},230:function(t,e){t.ticks||(0===e.data?e.loopInitiated?e.loops===e.loopCount&&(e.loopInitiated=!1):(e.loopInitiated=!0,e.loopStart=t.row,e.loopCount=0):e.loopInitiated&&(t.rowJump=e.loopStart,e.loopCount?e.loops++:(e.loopCount=e.data,e.loops=1)))},233:function(t,e){(t.ticks+1)%e.data||(console.log("retriggering note!",t.ticks+1),e.samplePos=0,e.done=!1)},234:function(t,e){t.ticks||(e.volume+=e.data,e.volume>63&&(e.volume=63))},235:function(t,e){t.ticks||(e.volume-=e.data,e.volume<0&&(e.volume=0))},237:function(t,e){t.ticks||(e.delay=e.data)},238:function(t,e){t.ticks||(t.rowRepeat?t.rowRepeat&&t.rowRepeat--:(t.rowRepeat=e.data,console.log("setting repeat to",t.rowRepeat)))},15:function(t,e){t.ticks||(e.data<32?t.speed=e.data:(t.bpm=e.data,t.calcTickSpeed()))}};
 //# sourceMappingURL=modplayer-js.js.map
diff --git a/js/mod-processor.js b/js/mod-processor.js
index 55d4713..4d63ea7 100644
--- a/js/mod-processor.js
+++ b/js/mod-processor.js
@@ -46,7 +46,6 @@ class PTModuleProcessor extends AudioWorkletProcessor{
         // pattern data always starts at offset 1084
         super();
         this.port.onmessage = this.handleMessage.bind(this);
-        this.patternOffset = 1084;
         this.patternLength = 1024;
     }
 
@@ -195,7 +194,8 @@ class PTModuleProcessor extends AudioWorkletProcessor{
                 vspeed: 0,
                 vpos: 0,
                 loopInitiated: false,
-                id: i
+                id: i,
+                cmd: 0
             };
             if (!this.channels[i]) {
                 this.channels[i] = channel;
@@ -240,6 +240,12 @@ class PTModuleProcessor extends AudioWorkletProcessor{
         // but we stick to good old ST/NT modules
         const str = BinUtils.readAscii(this.buffer, 4, 1080);
         this.maxSamples = str.match("M.K.") ? 31 : 15;
+
+        if (this.maxSamples === 15) {
+            this.patternOffset = 1080 - 480;
+        } else {
+            this.patternOffset = 1084;
+        }
     }
 
     /**
@@ -278,11 +284,12 @@ class PTModuleProcessor extends AudioWorkletProcessor{
             this.tick();
             for (let chan = 0; chan < this.channels.length; ++chan) {
                 const channel = this.channels[chan];
-                const buffer = this.audioWorkletSupport ? outputs[chan][0] : outputs[0][outputChannel];
                 // select left/right output depending on module channel:
                 // voices 0,3 go to left channel, 1,2 go to right channel
                 outputChannel = outputChannel ^ (chan & 1);
 
+                const buffer = this.audioWorkletSupport ? outputs[chan][0] : outputs[0][outputChannel];
+
                 // TODO: check that no effect can be applied without a note
                 // otherwise that will have to be moved outside this loop
                 if (this.newTick && channel.cmd) {
@@ -472,6 +479,10 @@ class PTModuleProcessor extends AudioWorkletProcessor{
             // Existing mod players seem to play a sample only once if repeatLength is set to 2
             if (sample.repeatLength === 2) {
                 sample.repeatLength = 0;
+                // some modules seems to skip the first two bytes for length
+                if (sample.length === 2) {
+                    sample.length = 0;
+                }
             }
 
             if (sample.repeatLength > sample.length) {
@@ -487,7 +498,8 @@ class PTModuleProcessor extends AudioWorkletProcessor{
 
     getPatternData() {
         // pattern data always starts at offset 950
-        const uint8buffer = new Uint8Array(this.buffer, 950);
+        const offset = this.maxSamples === 15 ? 470 : 950;
+        const uint8buffer = new Uint8Array(this.buffer, offset);
         this.songLength = uint8buffer[0];
         let position = 2;
         let max = 0;
@@ -515,7 +527,8 @@ class PTModuleProcessor extends AudioWorkletProcessor{
         for (let i = 0; i < this.samples.length; ++i) {
             const length = this.samples[i].length,
                 data = new Float32Array(length),
-                pcm = new Int8Array(this.buffer, offset, length);
+                maxLength = (offset + length) > this.buffer.byteLength ? this.buffer.byteLength - offset : length,
+                pcm =  new Int8Array(this.buffer, offset, maxLength);
 
             // convert 8bit pcm format to webaudio format
             for (let j = 0; j < length; ++j) {
@@ -524,7 +537,7 @@ class PTModuleProcessor extends AudioWorkletProcessor{
 
             this.samples[i].data = data;
 
-            offset += length;
+            offset += maxLength;
         }
     }
 
diff --git a/package-lock.json b/package-lock.json
index 6b4d6ca..4119764 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -133,6 +133,12 @@
       "integrity": "sha1-odl8yvy8JiXMcPrc6zalDFiwGlM=",
       "dev": true
     },
+    "async": {
+      "version": "1.5.2",
+      "resolved": "https://registry.npmjs.org/async/-/async-1.5.2.tgz",
+      "integrity": "sha1-7GphrlZIDAw8skHJVhjiCJL5Zyo=",
+      "dev": true
+    },
     "asyncro": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/asyncro/-/asyncro-3.0.0.tgz",
@@ -467,6 +473,12 @@
       "integrity": "sha512-RszJCAxg/PP6uzXVXL6BsxSXx/B05oJAQ2vkJRjyjrEcNVycaqOmNb5OTxZPE3xa5gwZduqza6L9JOCenh/Ecw==",
       "dev": true
     },
+    "corser": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/corser/-/corser-2.0.1.tgz",
+      "integrity": "sha1-jtolLsqrWEDc2XXOuQ2TcMgZ/4c=",
+      "dev": true
+    },
     "cosmiconfig": {
       "version": "2.2.2",
       "resolved": "https://registry.npmjs.org/cosmiconfig/-/cosmiconfig-2.2.2.tgz",
@@ -732,6 +744,15 @@
         }
       }
     },
+    "debug": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
+      "integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+      "dev": true,
+      "requires": {
+        "ms": "2.0.0"
+      }
+    },
     "decamelize": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/decamelize/-/decamelize-1.2.0.tgz",
@@ -759,6 +780,26 @@
       "integrity": "sha1-rOb/gIwc5mtX0ev5eXessCM0z8E=",
       "dev": true
     },
+    "ecstatic": {
+      "version": "3.3.0",
+      "resolved": "https://registry.npmjs.org/ecstatic/-/ecstatic-3.3.0.tgz",
+      "integrity": "sha512-EblWYTd+wPIAMQ0U4oYJZ7QBypT9ZUIwpqli0bKDjeIIQnXDBK2dXtZ9yzRCOlkW1HkO8gn7/FxLK1yPIW17pw==",
+      "dev": true,
+      "requires": {
+        "he": "^1.1.1",
+        "mime": "^1.6.0",
+        "minimist": "^1.1.0",
+        "url-join": "^2.0.5"
+      },
+      "dependencies": {
+        "minimist": {
+          "version": "1.2.0",
+          "resolved": "http://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
+          "dev": true
+        }
+      }
+    },
     "electron-to-chromium": {
       "version": "1.3.64",
       "resolved": "https://registry.npmjs.org/electron-to-chromium/-/electron-to-chromium-1.3.64.tgz",
@@ -804,6 +845,12 @@
       "integrity": "sha512-XpCnW/AE10ws/kDAs37cngSkvgIR8aN3G0MS85m7dUpuK2EREo9VJ00uvw6Dg/hXEpfsE1I1TvJOJr+Z+TL+ig==",
       "dev": true
     },
+    "eventemitter3": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/eventemitter3/-/eventemitter3-3.1.0.tgz",
+      "integrity": "sha512-ivIvhpq/Y0uSjcHDcOIccjmYjGLcP09MFGE7ysAwkAvkXfpZlC985pH2/ui64DKazbTW/4kN3yqozUxlXzI6cA==",
+      "dev": true
+    },
     "expand-brackets": {
       "version": "0.1.5",
       "resolved": "https://registry.npmjs.org/expand-brackets/-/expand-brackets-0.1.5.tgz",
@@ -896,6 +943,15 @@
         }
       }
     },
+    "follow-redirects": {
+      "version": "1.5.8",
+      "resolved": "https://registry.npmjs.org/follow-redirects/-/follow-redirects-1.5.8.tgz",
+      "integrity": "sha512-sy1mXPmv7kLAMKW/8XofG7o9T+6gAjzdZK4AJF6ryqQYUa/hnzgiypoeUecZ53x7XiqKNEpNqLtS97MshW2nxg==",
+      "dev": true,
+      "requires": {
+        "debug": "=3.1.0"
+      }
+    },
     "for-in": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/for-in/-/for-in-1.0.2.tgz",
@@ -1014,12 +1070,53 @@
       "integrity": "sha1-M7QHd3VMZDJXPBIMw4CLvRDUfwQ=",
       "dev": true
     },
+    "he": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/he/-/he-1.1.1.tgz",
+      "integrity": "sha1-k0EP0hsAlzUVH4howvJx80J+I/0=",
+      "dev": true
+    },
     "html-comment-regex": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/html-comment-regex/-/html-comment-regex-1.1.1.tgz",
       "integrity": "sha1-ZouTd26q5V696POtRkswekljYl4=",
       "dev": true
     },
+    "http-proxy": {
+      "version": "1.17.0",
+      "resolved": "https://registry.npmjs.org/http-proxy/-/http-proxy-1.17.0.tgz",
+      "integrity": "sha512-Taqn+3nNvYRfJ3bGvKfBSRwy1v6eePlm3oc/aWVxZp57DQr5Eq3xhKJi7Z4hZpS8PC3H4qI+Yly5EmFacGuA/g==",
+      "dev": true,
+      "requires": {
+        "eventemitter3": "^3.0.0",
+        "follow-redirects": "^1.0.0",
+        "requires-port": "^1.0.0"
+      }
+    },
+    "http-server": {
+      "version": "0.11.1",
+      "resolved": "https://registry.npmjs.org/http-server/-/http-server-0.11.1.tgz",
+      "integrity": "sha512-6JeGDGoujJLmhjiRGlt8yK8Z9Kl0vnl/dQoQZlc4oeqaUoAKQg94NILLfrY3oWzSyFaQCVNTcKE5PZ3cH8VP9w==",
+      "dev": true,
+      "requires": {
+        "colors": "1.0.3",
+        "corser": "~2.0.0",
+        "ecstatic": "^3.0.0",
+        "http-proxy": "^1.8.1",
+        "opener": "~1.4.0",
+        "optimist": "0.6.x",
+        "portfinder": "^1.0.13",
+        "union": "~0.4.3"
+      },
+      "dependencies": {
+        "colors": {
+          "version": "1.0.3",
+          "resolved": "https://registry.npmjs.org/colors/-/colors-1.0.3.tgz",
+          "integrity": "sha1-BDP0TYCWgP3rYO0mDxsMJi6CpAs=",
+          "dev": true
+        }
+      }
+    },
     "icss-replace-symbols": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/icss-replace-symbols/-/icss-replace-symbols-1.1.0.tgz",
@@ -1423,6 +1520,12 @@
         "regex-cache": "^0.4.2"
       }
     },
+    "mime": {
+      "version": "1.6.0",
+      "resolved": "https://registry.npmjs.org/mime/-/mime-1.6.0.tgz",
+      "integrity": "sha512-x0Vn8spI+wuJ1O6S7gnbaQg8Pxh4NNHb7KSINmEWKiPE4RKOplvijn+NkmYmmRgP68mc70j2EbeTFRsrswaQeg==",
+      "dev": true
+    },
     "minimatch": {
       "version": "3.0.4",
       "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
@@ -1459,6 +1562,12 @@
       "integrity": "sha1-haom09ru7t+A3FmEr5XMXKXK2fE=",
       "dev": true
     },
+    "ms": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",
+      "integrity": "sha1-VgiurfwAvmwpAd9fmGF4jeDVl8g=",
+      "dev": true
+    },
     "nodent-compiler": {
       "version": "3.2.9",
       "resolved": "https://registry.npmjs.org/nodent-compiler/-/nodent-compiler-3.2.9.tgz",
@@ -1540,6 +1649,22 @@
         "is-extendable": "^0.1.1"
       }
     },
+    "opener": {
+      "version": "1.4.3",
+      "resolved": "https://registry.npmjs.org/opener/-/opener-1.4.3.tgz",
+      "integrity": "sha1-XG2ixdflgx6P+jlklQ+NZnSskLg=",
+      "dev": true
+    },
+    "optimist": {
+      "version": "0.6.1",
+      "resolved": "https://registry.npmjs.org/optimist/-/optimist-0.6.1.tgz",
+      "integrity": "sha1-2j6nRob6IaGaERwybpDrFaAZZoY=",
+      "dev": true,
+      "requires": {
+        "minimist": "~0.0.1",
+        "wordwrap": "~0.0.2"
+      }
+    },
     "os-homedir": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/os-homedir/-/os-homedir-1.0.2.tgz",
@@ -1594,6 +1719,28 @@
       "integrity": "sha1-5aSs0sEB/fPZpNB/DbxNtJ3SgXY=",
       "dev": true
     },
+    "portfinder": {
+      "version": "1.0.17",
+      "resolved": "https://registry.npmjs.org/portfinder/-/portfinder-1.0.17.tgz",
+      "integrity": "sha512-syFcRIRzVI1BoEFOCaAiizwDolh1S1YXSodsVhncbhjzjZQulhczNRbqnUl9N31Q4dKGOXsNDqxC2BWBgSMqeQ==",
+      "dev": true,
+      "requires": {
+        "async": "^1.5.2",
+        "debug": "^2.2.0",
+        "mkdirp": "0.5.x"
+      },
+      "dependencies": {
+        "debug": {
+          "version": "2.6.9",
+          "resolved": "https://registry.npmjs.org/debug/-/debug-2.6.9.tgz",
+          "integrity": "sha512-bC7ElrdJaJnPbAP+1EotYvqZsb3ecl5wi6Bfi6BJTUcNowp6cvspg0jXznRTKDjm/E7AdgFBVeAPVMNcKGsHMA==",
+          "dev": true,
+          "requires": {
+            "ms": "2.0.0"
+          }
+        }
+      }
+    },
     "postcss": {
       "version": "6.0.23",
       "resolved": "https://registry.npmjs.org/postcss/-/postcss-6.0.23.tgz",
@@ -3587,6 +3734,12 @@
       "integrity": "sha1-fjL3W0E4EpHQRhHxvxQQmsAGUdc=",
       "dev": true
     },
+    "qs": {
+      "version": "2.3.3",
+      "resolved": "https://registry.npmjs.org/qs/-/qs-2.3.3.tgz",
+      "integrity": "sha1-6eha2+ddoLvkyOBHaghikPhjtAQ=",
+      "dev": true
+    },
     "query-string": {
       "version": "4.3.4",
       "resolved": "https://registry.npmjs.org/query-string/-/query-string-4.3.4.tgz",
@@ -3713,6 +3866,12 @@
       "integrity": "sha1-UpyczvJzgK3+yaL5ZbZJu+5jZBg=",
       "dev": true
     },
+    "requires-port": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/requires-port/-/requires-port-1.0.0.tgz",
+      "integrity": "sha1-kl0mAdOaxIXgkc8NpcbmlNw9yv8=",
+      "dev": true
+    },
     "reserved-words": {
       "version": "0.1.2",
       "resolved": "https://registry.npmjs.org/reserved-words/-/reserved-words-0.1.2.tgz",
@@ -4064,6 +4223,15 @@
         "source-map": "~0.6.1"
       }
     },
+    "union": {
+      "version": "0.4.6",
+      "resolved": "https://registry.npmjs.org/union/-/union-0.4.6.tgz",
+      "integrity": "sha1-GY+9rrolTniLDvy2MLwR8kopWeA=",
+      "dev": true,
+      "requires": {
+        "qs": "~2.3.3"
+      }
+    },
     "uniq": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/uniq/-/uniq-1.0.1.tgz",
@@ -4082,6 +4250,12 @@
       "integrity": "sha512-rBJeI5CXAlmy1pV+617WB9J63U6XcazHHF2f2dbJix4XzpUF0RS3Zbj0FGIOCAva5P/d/GBOYaACQ1w+0azUkg==",
       "dev": true
     },
+    "url-join": {
+      "version": "2.0.5",
+      "resolved": "https://registry.npmjs.org/url-join/-/url-join-2.0.5.tgz",
+      "integrity": "sha1-WvIvGMBSoACkjXuCxenC4v7tpyg=",
+      "dev": true
+    },
     "vendors": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/vendors/-/vendors-1.0.2.tgz",
@@ -4106,6 +4280,12 @@
       "integrity": "sha1-+HfVv2SMl+WqVC+twW1qJZucEaE=",
       "dev": true
     },
+    "wordwrap": {
+      "version": "0.0.3",
+      "resolved": "https://registry.npmjs.org/wordwrap/-/wordwrap-0.0.3.tgz",
+      "integrity": "sha1-o9XabNXAvAAI03I0u68b7WMFkQc=",
+      "dev": true
+    },
     "yallist": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/yallist/-/yallist-2.1.2.tgz",
diff --git a/package.json b/package.json
index 894b5be..9806e70 100644
--- a/package.json
+++ b/package.json
@@ -2,10 +2,9 @@
   "name": "modplayer-js",
   "version": "1.0.0",
   "description": "JavaScript player for SoundTracker/Noisetracker mod files using the webaudio AudioWorklet API.",
-  "main": "js/modplayer.js",
+  "main": "js/main.js",
   "scripts": {
-    "build": "microbundle",
-    "dev": "microbundle watch",
+    "build": "microbundle -i js/mod-processor.js -o dist && cp dist/modplayer-js.js js/mod-processor-es5.js",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   "repository": {
@@ -28,6 +27,7 @@
   },
   "homepage": "https://github.com/warpdesign/modplayer-js#readme",
   "devDependencies": {
+    "http-server": "^0.11.1",
     "microbundle": "^0.6.0"
   }
 }