AWARE: Music

This sensor module monitors the system music player using the MediaPlayer framework. It records playback state changes (playing, paused, stopped, etc.) and now-playing item changes (track changes), capturing metadata such as title, artist, album, genre, duration, and playback position.

Requirements

iOS 13 or later

Installation

1. Open Package Manager Windows

   • Open Xcode -> Select Menu Bar -> File -> App Package Dependencies...

2. Find the package using the manager

   • Select Search Package URL and type https://github.com/awareframework/com.awareframework.ios.sensor.music.git

3. Import the package into your target.

4. Add NSAppleMusicUsageDescription to your Info.plist.

Public functions

MusicSensor

• init(_ config: MusicSensor.Config): Initializes the sensor with the given configuration.
• start(): Requests media library authorization and begins observing playback notifications.
• stop(): Stops observing playback notifications.
• sync(force:): Syncs stored data to the configured host.
• set(label:): Sets a custom label applied to all subsequent data points.

MusicSensor.Config

Class to hold the configuration of the sensor.

Fields

• sensorObserver: MusicObserver?: Callback for live data updates.
• emitInitialState: Bool: If true, immediately fires callbacks for the current playback state and now-playing item when the sensor starts. (default = true)
• duplicateEventSuppressionInterval: TimeInterval: Minimum time interval (seconds) between identical events to suppress duplicates. (default = 1.0)
• enabled: Bool: Sensor is enabled or not. (default = false)
• debug: Bool: Enable/disable logging. (default = false)
• label: String: Label for the data. (default = "")
• deviceId: String: Id of the device associated with the events. (default = "")
• dbEncryptionKey: Encryption key for the database. (default = nil)
• dbType: Engine: Which db engine to use for saving data. (default = Engine.DatabaseType.NONE)
• dbPath: String: Path of the database. (default = "aware_music")
• dbHost: String: Host for syncing the database. (default = nil)

Broadcasts

Fired Broadcasts

• MusicSensor.ACTION_AWARE_MUSIC_PLAYBACK_STATE_CHANGED: fired when the playback state changes (playing, paused, stopped, etc.).
• MusicSensor.ACTION_AWARE_MUSIC_NOW_PLAYING_ITEM_CHANGED: fired when the now-playing track changes.

Received Broadcasts

• MusicSensor.ACTION_AWARE_MUSIC_START: received broadcast to start the sensor.
• MusicSensor.ACTION_AWARE_MUSIC_STOP: received broadcast to stop the sensor.
• MusicSensor.ACTION_AWARE_MUSIC_SYNC: received broadcast to send sync attempt to the host.
• MusicSensor.ACTION_AWARE_MUSIC_SET_LABEL: received broadcast to set the data label. Label is expected in the MusicSensor.EXTRA_LABEL field of the notification userInfo.

Data Representations

MusicData

Contains the playback event data.

Field	Type	Description
title	String	Song title
artist	String	Artist name
album	String	Album title
genre	String	Genre
duration	Double	Track duration in seconds
position	Double	Playback position at the event time in seconds (-1 if unavailable)
playbackState	Int	MPMusicPlaybackState raw value: 0=stopped, 1=playing, 2=paused, 3=interrupted, 4=seekFwd, 5=seekBwd
playbackRate	Double	Current playback rate (0.0=paused, 1.0=normal speed)
label	String	Customizable label. Useful for data calibration or traceability
deviceId	String	AWARE device UUID
timestamp	Int64	Unixtime milliseconds since 1970
timezone	Int	Timezone of the device
os	String	Operating system of the device (iOS)
jsonVersion	Int	JSON schema version

Example usage

import com_awareframework_ios_sensor_music

let sensor = MusicSensor(MusicSensor.Config().apply { config in
    config.sensorObserver = Observer()
    config.emitInitialState = true
    config.debug = true
})

sensor.start()

// Later...
sensor.stop()

class Observer: MusicObserver {
    func onPlaybackStateChanged(data: MusicData) {
        print("State:", data.playbackState, "Track:", data.title)
    }

    func onNowPlayingItemChanged(data: MusicData) {
        print("Now playing:", data.title, "-", data.artist)
    }
}

Author

Yuuki Nishiyama (The University of Tokyo), nishiyama@csis.u-tokyo.ac.jp

Related Links

• Apple | MediaPlayer
• Apple | MPMusicPlayerController

License

Copyright (c) 2018 AWARE Mobile Context Instrumentation Middleware/Framework (http://www.awareframework.com)

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.