CODEWITHSUNDEEP
javascriptnode.js
Per H
Per H

Reputation: 1542

Reading WAV volume data in node.js

I'm in dire need of help understanding how to read volume-levels for a WAV-file. Basically, I need a way to figure out the volume at specific times in an audio file (0.01s seconds in for example), in order to find specific "peaks".

I'm using node-wav (https://github.com/TooTallNate/node-wav) and the following code:

var file = fs.createReadStream('test.wav'),
  reader = new wav.Reader(),
  bufSize = 4410;

reader.on('readable', function() {
  while (null !== (chunk = reader.read(bufSize))) {
    // I'M TOTALLY LOST HERE
  }
});

Basically, I have no idea what bufSize to use (I'm pretty sure it depends on how "fine-tuned" i want the results.. Also I know I have to average the data in every chunk somehow, and I tried taking the average values etc. but can't seem to get any useful data..

Any help would be appreciated!

Upvotes: 1

Views: 4625

Answers (1)

tungd
tungd

Reputation: 14897

I don't think you need the bufSize here, just follow the example of wav.Reader:

var fs = require('fs');
var wav = require('wav');
var file = fs.createReadStream('track01.wav');
var reader = new wav.Reader();

// the "format" event gets emitted at the end of the WAVE header
reader.on('format', function (format) {
  // do your calculation here, using format
});

// pipe the WAVE file to the Reader instance
file.pipe(reader);

Anyway, according to the WAV file format, the size and the number of the data chunks can be extracted from the header block of a WAV file.

Upvotes: 1

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