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1 line
2.4 KiB
JavaScript
1 line
2.4 KiB
JavaScript
7 years ago
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function PCMPlayer(t){this.init(t)}PCMPlayer.prototype.init=function(t){this.option=Object.assign({},{encoding:"16bitInt",channels:1,sampleRate:8e3,flushingTime:1e3},t),this.samples=new Float32Array,this.flush=this.flush.bind(this),this.interval=setInterval(this.flush,this.option.flushingTime),this.maxValue=this.getMaxValue(),this.typedArray=this.getTypedArray(),this.createContext()},PCMPlayer.prototype.getMaxValue=function(){var t={"8bitInt":128,"16bitInt":32768,"32bitInt":2147483648,"32bitFloat":1};return t[this.option.encoding]?t[this.option.encoding]:t["16bitInt"]},PCMPlayer.prototype.getTypedArray=function(){var t={"8bitInt":Int8Array,"16bitInt":Int16Array,"32bitInt":Int32Array,"32bitFloat":Float32Array};return t[this.option.encoding]?t[this.option.encoding]:t["16bitInt"]},PCMPlayer.prototype.createContext=function(){this.audioCtx=new(window.AudioContext||window.webkitAudioContext),this.gainNode=this.audioCtx.createGain(),this.gainNode.gain.value=1,this.gainNode.connect(this.audioCtx.destination),this.startTime=this.audioCtx.currentTime},PCMPlayer.prototype.isTypedArray=function(t){return t.byteLength&&t.buffer&&t.buffer.constructor==ArrayBuffer},PCMPlayer.prototype.feed=function(t){if(this.isTypedArray(t)){t=this.getFormatedValue(t);var e=new Float32Array(this.samples.length+t.length);e.set(this.samples,0),e.set(t,this.samples.length),this.samples=e}},PCMPlayer.prototype.getFormatedValue=function(t){t=new this.typedArray(t.buffer);var e,i=new Float32Array(t.length);for(e=0;e<t.length;e++)i[e]=t[e]/this.maxValue;return i},PCMPlayer.prototype.volume=function(t){this.gainNode.gain.value=t},PCMPlayer.prototype.destroy=function(){this.interval&&clearInterval(this.interval),this.samples=null,this.audioCtx.close(),this.audioCtx=null},PCMPlayer.prototype.flush=function(){if(this.samples.length){var t,e,i,n,a,s=this.audioCtx.createBufferSource(),r=this.samples.length/this.option.channels,o=this.audioCtx.createBuffer(this.option.channels,r,this.option.sampleRate);for(e=0;e<this.option.channels;e++)for(t=o.getChannelData(e),i=e,a=50,n=0;n<r;n++)t[n]=this.samples[i],n<50&&(t[n]=t[n]*n/50),r-51<=n&&(t[n]=t[n]*a--/50),i+=this.option.channels;this.startTime<this.audioCtx.currentTime&&(this.startTime=this.audioCtx.currentTime),console.log("start vs current "+this.startTime+" vs "+this.audioCtx.currentTime+" duration: "+o.duration),s.buffer=o,s.connect(this.gainNode),s.start(this.startTime),this.startTime+=o.duration,this.samples=new Float32Array}};
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