我正在尝试使用Web音频Api获取每分钟的节拍(BPM),就像在以下链接(http://joesul.li/van/beat-detection-using-web-audio/或https://github.com/JMPerez/beats-audio-api/blob/gh-pages/script.js)中所做的一样,但从音频流(麦克风)中获得。 不幸的是,我没有让它运行。 有人知道我如何将麦克风MediaStreamSource转换为BufferSource并像在第一个链接的网站上那样继续吗? 这是我现在要讲的代码:
navigator.mediaDevices.getUserMedia({ audio: true, video: false })
.then(function(stream) {
/* use the stream */
var OfflineContext = window.OfflineAudioContext || window.webkitOfflineAudioContext;
var source = OfflineContext.createMediaStreamSource(stream);
source.connect(OfflineContext);
var offlineContext = new OfflineContext(2, 30 * 44100, 44100);
offlineContext.decodeAudioData(stream, function(buffer) {
// Create buffer source
var source = offlineContext.createBufferSource();
source.buffer = buffer;
// Beats, or kicks, generally occur around the 100 to 150 hz range.
// Below this is often the bassline. So let's focus just on that.
// First a lowpass to remove most of the song.
var lowpass = offlineContext.createBiquadFilter();
lowpass.type = "lowpass";
lowpass.frequency.value = 150;
lowpass.Q.value = 1;
// Run the output of the source through the low pass.
source.connect(lowpass);
// Now a highpass to remove the bassline.
var highpass = offlineContext.createBiquadFilter();
highpass.type = "highpass";
highpass.frequency.value = 100;
highpass.Q.value = 1;
// Run the output of the lowpass through the highpass.
lowpass.connect(highpass);
// Run the output of the highpass through our offline context.
highpass.connect(offlineContext.destination);
// Start the source, and render the output into the offline conext.
source.start(0);
offlineContext.startRendering();
});
})
.catch(function(err) {
/* handle the error */
alert("Error");
});
谢谢!
答案 0 :(得分:1)
这些文章很棒。您当前的方法存在一些问题: