chromecaster-lib v0.5.3

node-chromecaster-lib

A library to send your input sound to the Chromecast.

Offers a simple way to get audio from system, discovering Chromecasts and sending audio to it. Audio codec is in your hands.

This version is in (kind of) beta, so any help is welcome.

Installation

This library currently works on OS X and Linux and Windows.

$ npm install chromecaster-lib

It is not needed to have installed portaudio to compile the library. But you must provide the library either by installing it using the aproppiate package manager (on Linux and macOS) or providing the library manually (on Windows and macOS).

For electron 1.4 and 1.8, node 8 and 10, it will download a compiled version from Github. Uses the library portaudio. To execute, the library can be put on an accessible path or can be put anywhere and load it using AudioInput.loadNativeLibrary(String).

Mac Users: You should install portaudio using brew install portaudio.

Linux Users: You should install portaudio19-dev and must install libavahi-compat-libdnssd-dev packages before installing this one.

Windows Users:

• You must install Apple "Bonjour SDK for Windows" (look for it on Google), and check for the variable BONJOUR_SDK_HOME in your CMD.
• If you have problems compiling this library (or one of its dependencies), see this issue.
• You can compile portaudio for 64bit or search a .dll on the internet. (optionally) Follow the instructions in build/msvc/readme.txt to make it compile. Use release version. To test/use the library, copy the portaudio_x64.dll into the root of the project.

Example

A quick, example (using lame encoder):

const { AudioInput, ChromecastDiscover, Webcast } = require('chromecaster-lib');
const lame = require('lame');

let cd = new ChromecastDiscover();
cd.on('deviceUp', function(name) {
    cd.stop();
    let client = cd.createClient(name);
    let encoder = new lame.Encoder({
        channels: 2,
        bitDepth: 16,
        sampleRate: 44100,
        bitRate: 320,
        outSampleRate: 44100,
        mode: lame.JOINTSTEREO
    });
    let audioInput = new AudioInput();
    let webcast = new Webcast({ port: 8080 });

    audioInput.on('data', encoder.write.bind(encoder));
    encoder.on('data', webcast.write.bind(webcast));

    client.setWebcast(webcast);
    client.connect((err, status) => {
        if(err) {
            console.log("Could not connect to CA: %s", err);
        } else {
            console.log("Connected to CA");
        }
    });
});
cd.start();

API

AudioInput

inherits from EventEmitter

constructor(options) Creates the object passing some options. options object can contain the following fields, and its default values

• samplerate Sample rate of the input audio stream. Valid values are: 44100, 48000, 88200, 96000 44100
• bps Bitdepth for sample. Could be 8, 16, 24, 32 16
• channels Number of channels of the stream, 1 (mono) or 2 (stereo) 2
• deviceName name of the device which capture the audio system default

• timePerFrame number of milliseconds to capture per frame 100ms

  NOTE: Invalid values in the above options will use the default value.

  NOTE: For deviceName, try with any value from AudioInput.getDevices().

  Observation: If the native library is not loaded, the constructor will throw an Error.

Number open() Opens the Input Audio Stream. If the return value is different from 0, then an error has occurred. In this case, see AudioInput.Error.

close() Closes the Input Stream, in case it was opened.

pause() (Un)Pauses the Input Stream.

Boolean isOpen() Returns true if the stream is open, false otherwise.

Boolean isPaused() Returns true if the stream is open and paused, or is closed.

event 'data' Every processed frame, will be emitted on this event. Event has only one argument: the interleaved audio buffer.

String AudioInput.error(Number)

Converts the error returned in Number AudioInput.open() into a string.

String AudioInput.getDevices()

Returns the devices available in the system. Useful to change the input device when creating an AudioInput.

Boolean AudioInput.loadNativeLibrary(String)

Tries to load the native library portaudio from the path given. If the library is already loaded or cannot be found, it will throw an Error.

Boolean AudioInput.isNativeLibraryLoaded()

Returns true if the native library is loaded.

Webcast

inherits from stream.Writable

constructor(options) Creates a web server to send the input audio to the Chromecast (or something else), and opens the server. The options object and its default values:

• port port to listen on 3000
• contentType MIME type of the input stream audio/mp3

stop() Closes the server

write(buffer , encoding, cbk) Writes some bytes to the clients that are listening. Encoding is usually omitted.

get localIp Obtains the ip of the machine in the local network

get contentType Obtains the contentType of the input stream, that is, the stream that will output to the server.

get port Gets the port the server is listening on.

event 'connect' When some client is connected to the local web server. The event passes three arguments:

• id: some kind of id for the client connected the position on the internal clients array
• req: req object from express.js
• res: res object from express.js

event 'disconnect' When a client closes the connexion, this event is emitted passing the before mentioned id.

ChromecastDiscover

inherits from events.EventEmitter

constructor() Prepares the discovering of Chromecasts. No options required.

start() Starts searching for Chromecasts.

stop() Stops searching Chromecasts.

String getDeviceAddress(name) Gets the IP address of the device named.

String getDeviceNameForNumber(number) Gets the device number for the nth device that was found. number goes from 0 to devicesFound - 1.

forEachClient(cbk) Does a forEach on every device found passing its name to the callback.

ChromecastClient createClient(name) Creates a ChromecastDevice object for the named device.

event 'deviceUp' Event emitted when a device has been found. Argument is the name of the device.

event 'deviceDown' Event emitted when a device has been disconnected. Argument is the name of the device.

ChromecastDevice

inherits from events.EventEmitter

constructor(device) Is not recommended create ChromecastDevices directly, use instead ChromecastDiscover.createClient().

setWebcast(webcast) Sets the Webcast object that your are using. Is a mandatory call this method before calling connect .

connect(cbk) connect(streamName, cbk) Connects to the Chromecast device and sets its stream name to streamName of default name (Chromecaster lib stream). Callback have a signature of function(err, status).

Any error in the connexion, is reported calling the callback with err set to the error.

If the connexion succeeds, cbk will be called with err set to null and with the status of the device. The device will play automatically.

getVolume(cbk) Gets the volume of the device asynchronously. The signature of cbk is function(err, volume) where volume is a number between 0 and 1. If the client is not connected, err and volume are null.

setVolume(volume , cbk) Sets the volume of the device asynchronously. Volume is a number 0,1. Values not in the range are clamped. The signature of cbk is function(err, volume) where volume is a number between 0 and 1. If the client is not connected, err and volume are null.

isMuted(cbk) Gets if the device is muted or not asynchronously. cbk has signature of function(err, muted).

setMute(muted , cbk) Change mute of the device asynchronously. cbk has signature of function(err, muted).

play(cbk) Notifies the Chromecast to start playing. By default, the Chromecast is always playing.

pause(cbk) Notifies the Chromecast to pause the stream.

stop(cbk) Notifies the Chromecast to stop the stream.

close() Stops the stream and closes the connexion to the device.