文件名称：JSSoundRecorder 纯js 录音+处理
文件大小：211KB
文件格式：ZIP
更新时间：2021-04-30 11:08:20
JSRecorder
Record sounds / noises around you and turn them into music. It’s a work in progress, at the moment it enables you to record live audio straight from your browser, edit it and save these sounds as a WAV file. There's also a sequencer part where you can create small loops using these sounds with a drone synth overlaid on them. See it working: http://daaain.github.com/JSSoundRecorder Technology ---------- No servers involved, only Web Audio API with binary sound Blobs passed around! ### Web Audio API #### GetUserMedia audio for live recording Experimental API to record any system audio input (including USB soundcards, musical instruments, etc). ```javascript // shim and create AudioContext window.AudioContext = window.AudioContext || window.webkitAudioContext || window.mozAudioContext; var audio_context = new AudioContext(); // shim and start GetUserMedia audio stream navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia; navigator.getUserMedia({audio: true}, startUserMedia, function(e) { console.log('No live audio input: ' + e); }); ``` #### Audio nodes for routing You can route audio stream around, with input nodes (microphone, synths, etc), filters (volume / gain, equaliser, low pass, etc) and outputs (speakers, binary streams, etc). ```javascript function startUserMedia(stream) { // create MediaStreamSource and GainNode var input = audio_context.createMediaStreamSource(stream); var volume = audio_context.createGain(); volume.gain.value = 0.7; // connect them and pipe output input.connect(volume); volume.connect(audio_context.destination); // connect recorder as well - see below var recorder = new Recorder(input); } ``` ### WebWorker Processing (interleaving) record buffer is done in the background to not block the main thread and the UI. Also WAV conversion for export is also quite heavy for longer recordings, so best left to run in the background. ```javascript this.context = input.context; this.node = this.context.createScriptProcessor(4096, 2, 2); this.node.onaudioprocess = function(e){ worker.postMessage({ command: 'record', buffer: [ e.inputBuffer.getChannelData(0), e.inputBuffer.getChannelData(1) ] }); } ``` ```javascript function record(inputBuffer){ var bufferL = inputBuffer[0]; var bufferR = inputBuffer[1]; var interleaved = interleave(bufferL, bufferR); recBuffers.push(interleaved); recLength += interleaved.length; } function interleave(inputL, inputR){ var length = inputL.length + inputR.length; var result = new Float32Array(length); var index = 0, inputIndex = 0; while (index < length){ result[index++] = inputL[inputIndex]; result[index++] = inputR[inputIndex]; inputIndex++; } return result; } ``` ```javascript function encodeWAV(samples){ var buffer = new ArrayBuffer(44 + samples.length * 2); var view = new DataView(buffer); /* RIFF identifier */ writeString(view, 0, 'RIFF'); /* file length */ view.setUint32(4, 32 + samples.length * 2, true); /* RIFF type */ writeString(view, 8, 'WAVE'); /* format chunk identifier */ writeString(view, 12, 'fmt '); /* format chunk length */ view.setUint32(16, 16, true); /* sample format (raw) */ view.setUint16(20, 1, true); /* channel count */ view.setUint16(22, 2, true); /* sample rate */ view.setUint32(24, sampleRate, true); /* byte rate (sample rate * block align) */ view.setUint32(28, sampleRate * 4, true); /* block align (channel count * bytes per sample) */ view.setUint16(32, 4, true); /* bits per sample */ view.setUint16(34, 16, true); /* data chunk identifier */ writeString(view, 36, 'data'); /* data chunk length */ view.setUint32(40, samples.length * 2, true); floatTo16BitPCM(view, 44, samples); return view; } ``` ### Binary Blob Instead of file drag and drop interface this binary blob is passed to editor. Note: BlobBuilder deprecated (but a lot of examples use it), you should use Blob constructor instead! ```javascript var f = new FileReader(); f. { audio_context.decodeAudioData(e.target.result, function(buffer) { $('#audioLayerControl')[0].handleAudio(buffer); }, function(e) { console.warn(e); }); }; f.readAsArrayBuffer(blob); ``` ```javascript function exportWAV(type){ var buffer = mergeBuffers(recBuffers, recLength); var dataview = encodeWAV(buffer); var audioBlob = new Blob([dataview], { type: type }); this.postMessage(audioBlob); } ``` ### Virtual File – URL.createObjectURL You can create file download link pointing to WAV blob, but also set it as the source of an Audio element. ```javascript var url = URL.createObjectURL(blob); var audioElement = document.createElement('audio'); var downloadAnchor = document.createElement('a'); audioElement.controls = true; audioElement.src = url; downloadAnchor.href = url; ``` TODO ---- * Sequencer top / status row should be radio buttons :) * Code cleanup / restructuring * Enable open / drag and drop files for editing * Visual feedback (levels) for live recording * Sequencer UI (and separation to a different module) Credits / license ----------------- Live recording code adapted from: http://www.phpied.com/files/webaudio/record.html Editor code adapted from: https://github.com/plucked/html5-audio-editor Copyright (c) 2012 Daniel Demmel MIT License
【文件预览】：
JSSoundRecorder-gh-pages
----bootstrap()
--------img()
--------js()
--------css()
----index.html(13KB)
----config.ru(62B)
----js()
--------sequencer.js(1KB)
--------lib()
--------recordLive.js(4KB)
--------drone.js(3KB)
----jquery()
--------js()
----README.md(6KB)
----app()
--------mainstyle.css(10KB)
--------js()