web-audio-api

Is it possible to use the Analyser node in the offlineAudioContext to do frequency analysis? I found out that ScriptProcessor 's onaudioprocess event still fires in the offlineAudioContext and this was the only event source I could use to call getByteFrequencyData of the Analyser Node. As below: var offline = new offlineAudioContext(1, buffer.length, 44100); var bufferSource = offline.createBufferSource(); bufferSource.buffer = buffer; var analyser = offline.createAnalyser(); var scp = offline.createScriptProcessor(256, 0, 1); bufferSource.connect(analyser); scp.connect(offline.destination); /

I have blob type generated by webaudio API, but the file that is saved have to high sample rate. How can I convert it to lower maybe something like https://developer.mozilla.org/en-US/docs/Web/API/OfflineAudioContext can help? Here is some sample of code: var xhr = new XMLHttpRequest(); /* HERE IS SOME CONVERTATION TO LOWER RATE */ var fd = new FormData(); fd.append("randomname", bigBlob); xhr.open("POST",url,false); xhr.send(fd); xhr.onload=function(e) { alert(e.target.responseText); }; Create an OfflineAudioContext with the rate you want at the end, and the number of frames there will be at

Chrome for Android versions 30 and 31 beta on Android 4.1 do not appear to correctly record audio using HTML5 web audio and navigator.webkitGetUserMedia. (Chrome 30+ on Android is supposed to support these APIs.) The symptom is that the code appears to work correctly, including displaying the prompt for whether or not to allow microphone access, but recorded data contains nothing but zeros. I created a simplified testcase (go to http://jsfiddle.net/JCFtK/ , and click Record button, then choose the appropriate option to allow it to access your microphone). The key part of the code is below (

I'm capturing audio input from microphone with getUserMedia() function, works fine in chrome, but in firefox sound dies out after 5 seconds. If I send request for microphone again (without reloading the page) same thing happens. Here is the code (I used http://updates.html5rocks.com/2012/09/Live-Web-Audio-Input-Enabled as guidance): //getting the function depending on browser navigator.getMedia = ( navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia); // success callback when requesting audio input stream function gotAudioStream

I want to mix two audio sources by put one song as background of another into single source. for example, i have input : <input id="files" type="file" name="files[]" multiple onchange="handleFilesSelect(event)"/> And script to decode this files: window.AudioContext = window.AudioContext || window.webkitAudioContext; var context = new window.AudioContext(); var sources = []; var files = []; var mixed = {}; function handleFilesSelect(event){ if(event.target.files.length <= 1) return false; files = event.target.files; readFiles(mixAudioSources); } function readFiles(index, callback){ var freader

I want to use WebAudio(AudioContext) in NodeJS. However NodeJS does not support WebAudio. There is an npm for web-audio-api but it is still in alpha stage and is incomplete. So how can I use WebAudio(AudioContext) in NodeJS. Can I instantiate a chrome browser environment from NodeJS and utilize its capabilties. Is this possible? Is there any other way to do it? Please help. You can use node-webkit or app.js to use WebAudio API and talk with it with socket.io. 来源： https://stackoverflow.com/questions/25197708/using-webaudio-api-from-nodejs

How can I specify the codecs used with the MediaRecorder API ? The only option I see is for mimeType which isn't really sufficient. Cramming in the codecs in the mimeType option doesn't seem to work. var mediaRecorder = new MediaRecorder( outputMediaStream ), { mimeType: 'video/webm; codecs="opus,vp8"' } ); This results in a WebM stream with Vorbis and VP8: FFMPEG STDERR: Input #0, matroska,webm, from 'pipe:': Metadata: encoder : QTmuxingAppLibWebM-0.0.1 Duration: N/A, start: 0.000000, bitrate: N/A Stream #0:0(eng): Video: vp8, yuv420p, 640x360, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 1k tbn, 1k tbc

I would like to read an MP3 stream (from icecast, to read ICY metadata an then pass the binary MP3 data to a Web Audio Api). Firefox has a "moz-chunked-arraybuffer" xhr responseType to read data on progress, but I can't find any equivalent for webkit / chrome. EDIT 2014/02/03 : Chrome has started implementing xhr.responseType "stream" The "parsing" is landed in Chrome (with the --enable-experimental-webkit-features flag) but the xhr.response resulted object (Stream) is not yet useable directly in Javascript : https://code.google.com/p/chromium/issues/detail?id=240603 EDIT 2014/07/10 : The spec

So that I can use the information to coordinate a page animation like making elements brighter as the decibel levels get higher Kevin Ennis This approach will work in Chrome / Safari: +function(){ var ctx = new AudioContext() , url = 'https://cf-media.sndcdn.com/OfjMZo27DlvH.128.mp3?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiKjovL2NmLW1lZGlhLnNuZGNkbi5jb20vT2ZqTVpvMjdEbHZILjEyOC5tcDMiLCJDb25kaXRpb24iOnsiRGF0ZUxlc3NUaGFuIjp7IkFXUzpFcG9jaFRpbWUiOjE1MTUwNDM5Njd9fX1dfQ__&Signature=FfmL2qUssAKs3Z7EPoYo0Yq8-SAg8rKLPs65EasXwuVkfsOB4joFqeCvVR2elpaG-lJaV4hXpXFiRCDWXNOYyAtO4Oz~sexiPwIoSk8