我试图创建一个项目,从互联网中获取实时流媒体音频文件,并连续取样音频以寻找给定时间段内的最主导频率。想法是,如果它在一段时间内(几秒钟)检测到440Hz的频率,那么意味着在实时流媒体上播放了特定的音调。一旦检测到特定音调,我会让它在程序中执行其他操作。直播流可以是讲话、单个音调或静音。
我已经能够做到这一点,并得到了一个来自在线音调生成器生成的文件的概念验证结果。当我传入该文件时,它可以正确地识别频率(只有1或2 Hz的误差)。当我拉入实时流时,我得到的频率数据大约是:17704Hz。我猜测这是来自实时流的“噪声”。
我正在使用npm模块node-pitchfinder和audio-analyer进行大部分处理
如何获取单个音调的任何想法?
const fs = require('fs');
const fsa = require('fs-extra');
const Lame = require('lame');
const Speaker = require('speaker');
const Volume = require('pcm-volume');
const Analyser = require('audio-analyser')
const request = require('request')
const Chunker = require('stream-chunker');
const { YIN } = require('node-pitchfinder')
const detectPitch = YIN({ sampleRate: 44100})
//const BUFSIZE = 64;
const BUFSIZE = 500;
var decoder = new Lame.Decoder();
decoder.on('format', function(format){onFormat(format)});
var chunker = Chunker(BUFSIZE);
chunker.pipe(decoder);
var options = {
url: 'http://relay.broadcastify.com/fq85hty701gnm4z.mp3',
headers: {
"Upgrade-Insecure-Requests": 1,
"Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
"User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Safari/605.1.15"
}
}
var audio_stream = request(options);
//var audio_stream = fs.createReadStream('./2000.mp3');
audio_stream.pipe(chunker);
function onFormat(format)
{
//if (volume == "undefined")
volume = 1.0;
vol = new Volume(volume);
speaker = new Speaker(format);
analyser = createAnalyser(format);
analyser.on('data', sample);
console.log(format);
vol.pipe(speaker);
vol.pipe(analyser);
decoder.pipe(vol);
vol.setVolume(volume);
}
function createAnalyser(format)
{
return new Analyser({
fftSize: 8,
bufferSize: BUFSIZE,
'pcm-stream': {
channels: format.channels,
sampleRate: format.sampleRate,
bitDepth: format.bitDepth
}
});
}
var logFile = 'log.txt';
var logOptions = {flag: 'a'};
function sample()
{
if (analyser) {
const frequency = detectPitch(analyser._data)
console.log(frequency)
}
}