Created attachment 222306 [details] html file with a similar script imbedded. When loaded, sound starts playing. When the bug is fixed, it will play with pitch oscillating. With this graph, vibrato should occur. bufferSource.playbackRate < gain < oscillator. In other words, connecting an oscillator (via gain to control depth) to the playbackRate audio parameter of a bufferSource node should change the pitch of a playing sound. The following script should cause the frequency of the bufferSource to range between 220Hz to 880Hz in a sinewave. var c = window.webkitAudioContext ? new webkitAudioContext() : new AudioContext(), b=c.createBuffer(1, 441, 44100), //one cycle of a 440Hz waveform at 44100 samples per sec d=b.getChannelData(0), //a float32 array (to store generated data). n=c.createBufferSource(), //to play the buffer amp=c.createGain(), //the amplitude of vibrato master = c.createGain(), //so we don't blast our ears off lfo = c.createOscillator(); //the oscillator for pitch change n.playbackRate = 1.5; //depth will be 0.5, taking playbackRate from 1 (when osc = -0.5) to 2 (when osc is .5); amp.gain.value = 0.5; //oscillator between -0.5 and .5 lfo.frequency.value = 4; //happens 4 times/second (you knew that) lfo.type = "sine"; master.connect(c.destination); //keep the sound down n.connect(master); //bufferSource amp.connect(n.playbackRate); //***THE BUG starts here** playbackRate doesn't oscillate. lfo.connect(amp); //lfo oscillates from -1 to 1, amp can make that larger or smaller. //suppose we loaded a file in the buffer. Data generated below to demonstrate bug. //generates a sort of sawtooth. for (var i = 0; i < 441; i++) d[i] = i / 441; master.gain.value = 0.2; n.buffer = b; //our generated buffer n.loop = true; //loops so get continuous sound n.start(0); //start the sound lfo.start(0); //start vibrato
<rdar://problem/15912715>
Some info not sticking. This is the web audio component, I am using Version 7.0.1 (9537.73.11, 538+) Sorry for the multiple mods.