WAV Info for Node.JS

#### A lightweight module that parses WAV information data from a wav file or buffer containing wav data into a Javascript Object. Basically retrieves file and header meta data information from a WAV file.

$3

- Determining the validity of a .wav file
- Detecting the bit depth / bit rate / bits per sample of a .wav file
- Detecting the Sample Rate of a .wav file
- Detecting the number of channels in a .wav file
- Retrieving the file information, including file size, created date etc

$3

``
npm install wav-info --save
`

`javascript
var wavInfo = require('wav-info');

wavInfo.infoByFile(WAV_FILE_PATH, function(err, info) { // './test.wav', '/audio/test.wav'
if (err) throw err;
console.log(info);
});

wavInfo.infoByBuffer(WAV_FILE_BUFFER, function(err, info) {
if (err) throw err;
console.log(info);
});
`
#### if err is not null, the WAV file is valid.

From the command line you can run:

`
node wfi.js
`




$3

`
{ header:
{ riff_head: 'RIFF',
chunk_size: 1697504,
wave_identifier: 'WAVE',
fmt_identifier: 'fmt ',
subchunk_size: 16,
audio_format: 1,
num_channels: 2,
sample_rate: 44100,
byte_rate: 45328,
block_align: 4,
bits_per_sample: 16,
data_identifier: 'PAD ' },
stats:
{ dev: 16777220,
mode: 33184,
nlink: 1,
uid: 501,
gid: 20,
rdev: 0,
blksize: 4096,
ino: 71128242,
size: 1697512,
blocks: 3320,
atime: Sun Nov 29 2015 10:13:15 GMT-0700 (MST),
mtime: Sat May 23 2015 12:45:00 GMT-0600 (MDT),
ctime: Thu Nov 12 2015 14:31:37 GMT-0700 (MST),
birthtime: Sat May 23 2015 12:44:55 GMT-0600 (MDT)
},
duration: 9.623038548752834
}
`

$3

`
{ header:
{ riff_head: 'RIFF',
chunk_size: 1697504,
wave_identifier: 'WAVE',
fmt_identifier: 'fmt ',
subchunk_size: 16,
audio_format: 1,
num_channels: 2,
sample_rate: 44100,
byte_rate: 45328,
block_align: 4,
bits_per_sample: 16,
data_identifier: 'PAD ' },
stats:
{ size: 1697512,
},
duration: 9.623038548752834
}
`

$3

`
{ error: true,
invalid_reasons:
[ 'Expected "RIFF" string at 0',
'Expected "WAVE" string at 4',
'Expected "fmt " string at 8',
'Unknown format: 25711',
'chunk_size does not match file size' ] }
``

Duration is in seconds. Stats on infoByFile come from Node raw fs.statSync() result.

References:
http://soundfile.sapp.org/doc/WaveFormat/

TODO: Deep scan [avg amplitude, max amplitude], fork for AIFF