H5采集pcm流转换采样率实时发送到服务端

    function startTalk(ws2, button) {
        var arrBuffer = new ArrayBuffer(320 * 2);
        var sendBuffer = new DataView(arrBuffer);
        var sendBufferindex  = 0;
        if (navigator.getUserMedia) {
            navigator.getUserMedia(
                { audio: true },
                function (stream) {
                    button.text("挂 断")
                    button.attr("status","doing")
                    var context = new AudioContext();
                    var audioInput = context.createMediaStreamSource(stream);
                    var recorder = context.createScriptProcessor(1024, 1, 1);
                    audioInput.connect(recorder);
                    recorder.connect(context.destination);
                    recorder.onaudioprocess = function (e) {
                        var buffer = e.inputBuffer.getChannelData(0);
                        var arrayBuffer = context.createBuffer(1, 1024, context.sampleRate);
                        var nowBuffering = arrayBuffer.getChannelData(0);
                        for (var i = 0; i < arrayBuffer.length; i++) {
                            nowBuffering[i] = buffer[i]
                        }
                        var offctx = new OfflineAudioContext(1, parseInt(1024*16000/context.sampleRate), 16000);
                        var source = offctx.createBufferSource();
                        source.buffer = arrayBuffer;
                        source.connect(offctx.destination);
                        source.start();
                        offctx.startRendering().then(function(renderedBuffer) {
                            var channetData = renderedBuffer.getChannelData(0)
                            source.stop();
                            var index = 0
                            var length = channetData.length
                            while (index < length) {
                                var selectBuffer = channetData[index]
                                var s = Math.max(-1, Math.min(1, selectBuffer));
                                var point = s < 0 ? s * 0x8000 : s * 0x7FFF;
                                if (sendBufferindex < 320 * 2) {
                                    sendBuffer.setInt16(sendBufferindex, point, true);
                                } else {
                                    var sendData = {
                                        "cmd":"pcm",
                                        "data":{
                                            "buffer": Array.from(new Int16Array(arrBuffer)),
                                            "timestamp": new Date().getTime(),
                                        }
                                    }
                                    if(ws2.readyState == ws2.CLOSING || ws2.readyState == ws2.CLOSED) {
                                        recorder.disconnect()
                                        return
                                    }
                                    ws2.send(JSON.stringify(sendData))
                                    
                                    sendBuffer = new DataView(arrBuffer);
                                    sendBufferindex = 0;
                                    sendBuffer.setInt16(sendBufferindex, point, true);
                                }
                                index++;
                                sendBufferindex = sendBufferindex + 2;
                            }
                        })
                        
                    }
                },
                function() {
                    ws2.close()
                    button.attr("status","close")
                    button.text("通 话")
                    alert('请插入耳机');