How to setup

Step 1 - Configuration: - Spout is required.
- Start your server with the plugin installed. The plugin will generate the necessary files for you.
- Shut down your server and change config.yml to your likings.

Step 2 - Adding music: There are two ways of adding music (or sounds). Either, you make use of the built-in webserver, or you provide links to where the music can be found.
You can use both methods simoultaneously.

<< Built-in Webserver >>

With this method, you place your sounds in a specific folder (probably AmbientSpout/Resources/Ambient or AmbientSpout/Resources/EffectLoop).

For .wav files: Simply drag and drop them in.
For .ogg files: Make the last 3 characters of the filename the length of the song in seconds. Say the song (or sound) is 1 min 32 long, 1*60sec + 32 = 92.
You name your file music092.ogg (or whichever other name you like).

Note that using the webserver will use bandwidth of your server.

<< Providing Links >>

In AmbientSpout/Resources you can find Ambient.txt. In this file, you can add links to sound files. Add them in this format, one per line:
<SONGLENGTH> <LINK>

Example:
123 http://google.com/song.ogg

NOTE: The link has to be a non-secure HTTP link, so not https://. I am saying this because DropBox gives https: links nowadays, just remove the s at the end .

Providing links is suggested (instead of webserver) if you fear the upload speed of your server is not the best, or you pay per bandwidth use.

Step 3 - OPTIONAL: Configuring WebServer: In case you want to make use of the built-in webserver, you will have to configure it.
In config.yml you have to add configure these fields:
HostAdress: Your host address (most likely the sameas the IP of the minecraft server.
HostPort: The port you want the webserver to run on (the default should be just fine in most cases).
EnableWebServer: Boolean value, do you want to use the webserver (you probably do, as you are reading this).

Example:
HostAdress: myawesomeserver.minecrafthost.com
HostPort: 5651
EnableWebServer: true

How do I know if the webserver is working?
Everything in the Resources folder is hosted. Because Ambient.txt is always present, try to go to this address:
http://HostAdress:HostPort/Ambient.txt

Example:
http://myawesomeserver.minecrafthost.com:5651/Ambient.txt

If you see the contents of your Ambient.txt file, then congratulations, it's working! (Note that Ambient.txt may be empty if you didn't add anything to it.)

"="-key is used to open the overlay by default.

A collection of posts about the functionality + configuration:

If anyone is interested in the current version, I can put it up here with a few instructions..

Screenshots:

Resources

Configuration

It will automatically find out the length of .wav files, unfortunately this is not possible (without adding an external library that is +100MB big) to do this automatically for .ogg files.
The easiest solution I found, is to put the duration of the ogg file in the name itself. The last 3 digits indicate the length in seconds.

"="-key is used to open the screen.
Put .ogg files in AmbientSpout/Resources/Ambient.
Last 3 characters of ogg filename must be the song length in seconds.

NOTE: Currently does not save player-data between server resets. So if a player disables music, and the server restarts, and the player starts again, it will be enabled (if DefaultOn is set to true, that is).

A little bit about the config:
Delaybetweensongs: that should be pretty clear. Delay between songs advised +30sec
DelayRandomness: Say you have 10 as delay, and 2 as randomness, the actual delay will be between 8 and 12 seconds.
FadeOutLength: Pretty straight-forward
DefaultOn: Do players start with music on when they (first) join?
MusicAreaEnabled: Not implemented yet, no effect.
DevMessage: Please keep this set on true, in case I join ;3
UseBackgroundImage: Whether you want to use a background image. Note: No need to worry about it overlapping the buttons, it will ALWAYS be in the back. Can be jpg or png, and can be transparent. For fullscreen: 427 by 240 pixels.
BackgroundImage: Link to the image you want to use.
EnableWebServer: Leave this on true, as it is the only way to have music , a list will probably be implemented later (so you can host files elsewhere, like the old AmbientSpout)
HostAddress: Put your server IP or hostname here.
HostPort: Pick a port you like

EffectLoops are effects that can be added quite easily to a specific place. For example, Seagull sounds in a harbor, waterfall sounds near a waterfall . As the name implies, they loop.

A few more things about new features..
-One can now add non-webserver sounds by adding lines to a text file, the first number indicating the length of said sound file.

- It now remembers whether or not the user has music enabled.
- Effectloops are saved in human-readable form, so one can easily edit it/add to it from outside.

In order:
ID (string name to be able to recognize said effectloop)
Length in seconds
URL
X coord
Y coord
Z coord
Worldname
VolumePercent
Distance it can be heard from
Active (enabled or not)
- Added metrics
- Quite a lot of performance improvements..

<< Note, you are going to have to add the effectloops manually for now, haven't finished the GUI for that yet . The future permission node: ambientspout.admin > This will already show a button to go to the effectloops management screen.

EffectLoops are effects that can be added quite easily to a specific place. For example, Seagull sounds in a harbor, waterfall sounds near a waterfall . As the name implies, they loop.

A few more things about new features..
-One can now add non-webserver sounds by adding lines to a text file, the first number indicating the length of said sound file.

- It now remembers whether or not the user has music enabled.
- Effectloops are saved in human-readable form, so one can easily edit it/add to it from outside.

AmbientSpout Reloaded