H5採集pcm流轉換採樣率實時發送到服務端

 1     function startTalk(ws2, button) {  2         var arrBuffer = new ArrayBuffer(320 * 2);  3         var sendBuffer = new DataView(arrBuffer);  4         var sendBufferindex  = 0;  5         if (navigator.getUserMedia) {  6             navigator.getUserMedia(  7                 { audio: true },  8                 function (stream) {  9                     button.text("掛 斷") 10                     button.attr("status","doing") 11                     var context = new AudioContext(); 12                     var audioInput = context.createMediaStreamSource(stream); 13                     var recorder = context.createScriptProcessor(1024, 1, 1); 14  audioInput.connect(recorder); 15  recorder.connect(context.destination); 16                     recorder.onaudioprocess = function (e) { 17                         var buffer = e.inputBuffer.getChannelData(0); 18                         var arrayBuffer = context.createBuffer(1, 1024, context.sampleRate); 19                         var nowBuffering = arrayBuffer.getChannelData(0); 20                         for (var i = 0; i < arrayBuffer.length; i++) { 21                             nowBuffering[i] = buffer[i] 22  } 23                         var offctx = new OfflineAudioContext(1, parseInt(1024*16000/context.sampleRate), 16000);
24                         var source = offctx.createBufferSource(); 25                         source.buffer = arrayBuffer; 26  source.connect(offctx.destination); 27  source.start(); 28                         offctx.startRendering().then(function(renderedBuffer) { 29                             var channetData = renderedBuffer.getChannelData(0) 30  source.stop(); 31                             var index = 0
32                             var length = channetData.length 33                             while (index < length) { 34                                 var selectBuffer = channetData[index] 35                                 var s = Math.max(-1, Math.min(1, selectBuffer)); 36                                 var point = s < 0 ? s * 0x8000 : s * 0x7FFF; 37                                 if (sendBufferindex < 320 * 2) { 38                                     sendBuffer.setInt16(sendBufferindex, point, true); 39                                 } else { 40                                     var sendData = { 41                                         "cmd":"pcm", 42                                         "data":{ 43                                             "buffer": Array.from(new Int16Array(arrBuffer)), 44                                             "timestamp": new Date().getTime(), 45  } 46  } 47                                     if(ws2.readyState == ws2.CLOSING || ws2.readyState == ws2.CLOSED) { 48  recorder.disconnect() 49                                         return
50  } 51  ws2.send(JSON.stringify(sendData)) 52                                     
53                                     sendBuffer = new DataView(arrBuffer); 54                                     sendBufferindex = 0; 55                                     sendBuffer.setInt16(sendBufferindex, point, true); 56  } 57                                 index++; 58                                 sendBufferindex = sendBufferindex + 2; 59  } 60  }) 61                         
62      } 63                 }, 64                 function() { 65  ws2.close() 66                     button.attr("status","close") 67                     button.text("通 話") 68                     alert('請插入耳機'); 69