Local Audio Share (Beta)

This feature is the analog of screen capture, but for audio. There may be cases where the application needs to stream music which is either stored in the device locally or from some other app present on the device in the room where the peer is joined.

Examples of such use cases can be a FM like application where the host would want to stream music while also interacting with others in the room or a host in a gaming app who would want to stream music from their device in the room along with their regular audio track.

How does audio share work

The Audio share option only works in Android 10 and above.

100ms SDK uses the MediaProjection APIs of Android to capture the device audio and stream it along with the user's regular audio track. To achieve this SDK starts a foreground service and starts capturing the device audio and mixes the bytes with the data collected from mic, so that the stream contains both system music and mic data.

This API gives apps the ability to copy the audio being played by other apps which have set its usage to USAGE_MEDIA, USAGE_GAME, or USAGE_UNKNOWN. (Audio from apps like YouTube etc can be captured)

How to stream device audio from the app (without a custom notification)

To start streaming device audio , app needs to call the startAudioshare method of HMSSDK, which takes in three parameters - The first one is HMSActionResultListener which is a callback object needed to inform about success or failure of the action The second one is an Intent which is the result data of MediaProjection permission activity; the calling app must validate that result code is Activity.RESULT_OK before calling this method. The third one is one of the modes of type AudioMixingMode in which the user wants to stream. This can be one out of the three available types - TALK_ONLY : only data captured by mic will be streamed in the room TALK_AND_MUSIC: data captured by mic as well as playback audio being captured from device will be streamed in the room MUSIC_ONLY: only the playback audio being captured from device will be streamed in the room

Following is the snippet on how to use this:

// Define a result Launcher var resultLauncher = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result -> if (result.resultCode == Activity.RESULT_OK) { val mediaProjectionPermissionResultData: Intent? = result.data // Pass this intent to hmsSDK hmsSDK.startAudioshare(object : HMSActionResultListener { override fun onError(error: HMSException) { // an error occurred } override fun onSuccess() { // started successfully } } ,mediaProjectionPermissionResultData, AudioMixingMode.TALK_AND_MUSIC) } } // Get the MEDIA_PROJECTION_SERVICE and launch the result launcher val mediaProjectionManager: MediaProjectionManager? = requireContext().getSystemService( Context.MEDIA_PROJECTION_SERVICE ) as MediaProjectionManager resultLauncher.launch(mediaProjectionManager?.createScreenCaptureIntent())

It is important to note that this API will not work if the resultCode is NOT Activity.RESULT_OK. SDK will also start a foreground service with a notification when it starts capturing the audio of the device.

How to add a custom notification

To take a look at how this is implemented in our sample app, click here.

hmssdk.startAudioShare also takes an optional fourth parameter of type notification. See how to build a custom notification in the android docs here.

It could look something like this: Since this is a standard Android notification the full range of customization is available.

fun startScreenshare(mediaProjectionPermissionResultData: Intent?, actionListener: HMSActionResultListener) { // Without custom notification // hmsSDK.startAudioshare(actionListener ,mediaProjectionPermissionResultData, AudioMixingMode.TALK_AND_MUSIC) // With custom notification val notification = NotificationCompat.Builder(getApplication(), "ScreenCapture channel") .setContentText("Screenshare running for roomId: ${hmsRoom?.roomId}") .setSmallIcon(R.drawable.arrow_up_float) .build() hmsSDK.startScreenshare(actionListener, mediaProjectionPermissionResultData, notification, AudioMixingMode.TALK_AND_MUSIC) }

How to change mode

To change the mode the user is streaming audio, call the setAudioMixingMode API and pass one of the modes out of TALK_ONLY or TALK_AND_MUSIC or MUSIC_ONLY

Note that TALK_ONLY mode is equivalent to regular mode, that is without starting this API

How to stop audio sharing

To stop capturing device audio and streaming into the room, call the stopAudioShare API and provide a HMSActionResultListener to listen to the success or error callbacks.

hmsSDK.stopAudioshare(object : HMSActionResultListener { override fun onError(error: HMSException) { // an error occurred } override fun onSuccess() { // stopped successfully } } )

It is advisable to call leave API from the onDestroy() of the activity/ fragment that

started the sharing of device audio otherwise the foreground service will be running if even user kills the app from the Recents tab.

DONOT forget to add the following permission for foreground service

<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

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