node-arecord/README.md

ALSA arecord wrapper for Node

node-arecord
===========

ALSA arecord wrapper for Node.js

This module was initially intended to provide basic audio capabilities in the Raspbian distribution of Debian on a Raspberry Pi platform. Node-arecord should however work on any Debian/Ubuntu system providing ALSA support has been installed.

ALSA stands for Advanced Linux Sound Architecture. It is a suite of hardware drivers, libraries and utilities which provide audio and MIDI functionality for the Linux operating system.

arecord is a simple native ALSA wav recorder.

Installation
-----------
### Debian/Ubuntu/Raspbian ###

#### Get ready ####

Before we start the real work, please update the system.
````
sudo apt-get update
sudo apt-get upgrade
````
If you are running on Raspberry Pi, please update Raspbian
````
sudo rpi-update
````

Install ALSA for audio playback
````
sudo apt-get install alsa-base alsa-utils
````

#### USB Audio on Raspberry Pi ####
If you are planning on using a USB audio on Raspberry Pi you will need to set your USB audio device as the default device.

Edit /etc/modprobe.d/alsa-base.conf and replaced the line:
````
options snd-usb-audio index=-2
````
With the following lines:
````
options snd-usb-audio index=0 nrpacks=1
options snd-bcm2835 index=-2
````

After a reboot of your Raspberry Pi
````
aplay -l
````
Should output the following:
````
**** List of PLAYBACK Hardware Devices ****
card 0: XXXX [XXXX], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
````

Your device volume will be set to 0 by default. Use the ALSA mixer to adjust the volume using your arrow keys:
````
alsamixer
````

API
---
#### new Sound(options)

Start the process and save the stdout of ALSA `arecord` tool to file

(Example : `new Sound({destination_folder: '/tmp', 'filename:'filename.wav'}).record();`)



Example Usage
-------------

````javascript
var Sound = require('node-arecord');

var sound = new Sound({
 debug: true,    // Show stdout
 destination_folder: '/tmp',
 filename: '/path/to/the/file/filename.wav',
 alsa_format: 'dat',
 alsa_device: 'plughw:1,0'
});

sound.record();

setTimeout(function () {
	sound.pause(); // pause the recording after five seconds
}, 5000);

setTimeout(function () {
	sound.resume(); // and resume it two seconds after pausing
}, 7000);

setTimeout(function () {
	sound.stop(); // stop after ten seconds
}, 10000);

// you can also listen for various callbacks:
sound.on('complete' function () {
	console.log('Done with recording!');
});
````