1 <input type="text" size="4" id="freq" value="440"><label for="hz">Hz</label>2 <button onclick="start()">play</button>3 <button onclick="stop()">stop</button>4 5 <script type="text/javascript"> 6 function AudioDataDestination(sampleRate, readFn) {7 // Initialize the audio output.8 var audio = new Audio();9 audio.mozSetup(1, sampleRate);10 11 var currentWritePosition = 0;12 var prebufferSize = sampleRate / 2; // buffer 500ms13 var tail = null;14 15 // The function called with regular interval to populate 16 // the audio output buffer.17 setInterval(function() {18 var written;19 // Check if some data was not written in previous attempts.20 if(tail) { 21 written = audio.mozWriteAudio(tail);22 currentWritePosition += written;23 if(written < tail.length) {24 // Not all the data was written, saving the tail...25 tail = tail.subarray(written);26 return; // ... and exit the function.27 }28 tail = null;29 }30 31 // Check if we need add some data to the audio output.32 var currentPosition = audio.mozCurrentSampleOffset();33 var available = currentPosition + prebufferSize - currentWritePosition;34 if(available > 0) {35 // Request some sound data from the callback function.36 var soundData = new Float32Array(parseFloat(available));37 readFn(soundData);38 39 // Writing the data.40 written = audio.mozWriteAudio(soundData);41 if(written < soundData.length) {42 // Not all the data was written, saving the tail.43 tail = soundData.slice(written);44 }45 currentWritePosition += written;46 }47 }, 100);48 }49 50 // Control and generate the sound.51 52 var frequency = 0, currentSoundSample;53 var sampleRate = 44100;54 55 function requestSoundData(soundData) {56 if (!frequency) { 57 return; // no sound selected58 }59 60 var k = 2* Math.PI * frequency / sampleRate;61 for (var i=0, size=soundData.length; i<size; i++) {62 soundData[i] = Math.sin(k * currentSoundSample++);63 } 64 }65 66 var audioDestination = new AudioDataDestination(sampleRate, requestSoundData);67 68 function start() {69 currentSoundSample = 0;70 frequency = parseFloat(document.getElementById("freq").value);71 }72 73 function stop() {74 frequency = 0;75 }76 </script>77 Este ShareCode tiene versiones:
- Hz play stop ... (24/04/2013)
- Hz play stop ... (24/04/2013)
- Hz play stop ... (24/04/2013)
- Hz play stop ... (24/04/2013)
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