restart video track api (#10)

@@ -78,8 +78,8 @@ internal constructor(
             listOf(this.sid)
         )
         // TODO: sendEncodings to customize
-        val transceiver =
-            engine.publisher.peerConnection.addTransceiver(track.rtcTrack, transInit)
+        val transceiver = engine.publisher.peerConnection.addTransceiver(track.rtcTrack, transInit)
+        track.transceiver = transceiver
 
         if (transceiver == null) {
             publishListener?.onPublishFailure(TrackException.PublishException("null sender returned from peer connection"))
@@ -108,8 +108,8 @@ internal constructor(
             listOf(this.sid)
         )
         // TODO: video encodings & simulcast
-        val transceiver =
-            engine.publisher.peerConnection.addTransceiver(track.rtcTrack, transInit)
+        val transceiver = engine.publisher.peerConnection.addTransceiver(track.rtcTrack, transInit)
+        track.transceiver = transceiver
 
         if (transceiver == null) {
             publishListener?.onPublishFailure(TrackException.PublishException("null sender returned from peer connection"))

@@ -2,6 +2,8 @@ package io.livekit.android.room.track
 
 import org.webrtc.MediaConstraints
 import org.webrtc.PeerConnectionFactory
+import org.webrtc.RtpSender
+import org.webrtc.RtpTransceiver
 import java.util.*
 
 /**
@@ -19,6 +21,10 @@ class LocalAudioTrack(
             rtcTrack.setEnabled(value)
         }
 
+    internal var transceiver: RtpTransceiver? = null
+    private val sender: RtpSender?
+        get() = transceiver?.sender
+
     companion object {
         internal fun createTrack(
             factory: PeerConnectionFactory,

@@ -11,20 +11,32 @@ import java.util.*
  * [startCapture] should be called before use.
  */
 class LocalVideoTrack(
-    private val capturer: VideoCapturer,
-    private val source: VideoSource,
+    private var capturer: VideoCapturer,
+    private var source: VideoSource,
     name: String,
-    private val options: LocalVideoTrackOptions,
-    rtcTrack: org.webrtc.VideoTrack
+    var options: LocalVideoTrackOptions,
+    rtcTrack: org.webrtc.VideoTrack,
+    private val peerConnectionFactory: PeerConnectionFactory,
+    private val context: Context,
+    private val eglBase: EglBase,
 ) : VideoTrack(name, rtcTrack) {
-    val dimensions: Dimensions
 
-    init {
-        dimensions = Dimensions(options.captureParams.width, options.captureParams.height)
-    }
+    override var rtcTrack: org.webrtc.VideoTrack = rtcTrack
+        internal set
+
+    val dimensions: Dimensions =
+        Dimensions(options.captureParams.width, options.captureParams.height)
+
+    internal var transceiver: RtpTransceiver? = null
+    private val sender: RtpSender?
+        get() = transceiver?.sender
 
     fun startCapture() {
-        capturer.startCapture(options.captureParams.width, options.captureParams.height, options.captureParams.maxFps)
+        capturer.startCapture(
+            options.captureParams.width,
+            options.captureParams.height,
+            options.captureParams.maxFps
+        )
     }
 
     override fun stop() {
@@ -32,6 +44,40 @@ class LocalVideoTrack(
         super.stop()
     }
 
+    fun restartTrack(options: LocalVideoTrackOptions = LocalVideoTrackOptions()) {
+        val newTrack = createTrack(
+            peerConnectionFactory,
+            context,
+            name,
+            options,
+            eglBase
+        )
+
+        val oldCapturer = capturer
+        val oldSource = source
+        val oldRtcTrack = rtcTrack
+
+        oldCapturer.stopCapture()
+        oldCapturer.dispose()
+        oldSource.dispose()
+
+        // sender owns rtcTrack, so it'll take care of disposing it.
+        oldRtcTrack.setEnabled(false)
+
+        // migrate video sinks to the new track
+        for (sink in sinks) {
+            oldRtcTrack.removeSink(sink)
+            newTrack.addRenderer(sink)
+        }
+
+        capturer = newTrack.capturer
+        source = newTrack.source
+        rtcTrack = newTrack.rtcTrack
+        this.options = options
+        startCapture()
+        sender?.setTrack(newTrack.rtcTrack, true)
+    }
+
     companion object {
         internal fun createTrack(
             peerConnectionFactory: PeerConnectionFactory,
@@ -55,6 +101,9 @@ class LocalVideoTrack(
                 options = options,
                 name = name,
                 rtcTrack = track,
+                peerConnectionFactory = peerConnectionFactory,
+                context = context,
+                eglBase = rootEglBase,
             )
         }
 

 package io.livekit.android.room.track
 
-import livekit.LivekitModels
 import org.webrtc.VideoSink
 import org.webrtc.VideoTrack
 
 open class VideoTrack(name: String, override val rtcTrack: VideoTrack) :
     Track(name, Kind.VIDEO, rtcTrack) {
-    private val sinks: MutableList<VideoSink> = ArrayList();
+    internal val sinks: MutableList<VideoSink> = ArrayList();
 
     var enabled: Boolean
         get() = rtcTrack.enabled()

@@ -12,8 +12,10 @@ import io.livekit.android.room.Room
 import io.livekit.android.room.RoomListener
 import io.livekit.android.room.participant.Participant
 import io.livekit.android.room.participant.RemoteParticipant
+import io.livekit.android.room.track.CameraPosition
 import io.livekit.android.room.track.LocalAudioTrack
 import io.livekit.android.room.track.LocalVideoTrack
+import io.livekit.android.room.track.LocalVideoTrackOptions
 import kotlinx.coroutines.launch
 
 class CallViewModel(
@@ -118,7 +120,19 @@ class CallViewModel(
     }
 
     fun flipVideo() {
-        // TODO
+        room.value?.localParticipant?.let { participant ->
+            val videoTrack = participant.videoTracks.values
+                .firstOrNull()
+                ?.track as? LocalVideoTrack
+                ?: return@let
+
+            val newOptions = when (videoTrack.options.position) {
+                CameraPosition.FRONT -> LocalVideoTrackOptions(position = CameraPosition.BACK)
+                CameraPosition.BACK -> LocalVideoTrackOptions(position = CameraPosition.FRONT)
+            }
+
+            videoTrack.restartTrack(newOptions)
+        }
     }
 }
 

@@ -4,7 +4,6 @@ import android.Manifest
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.os.Bundle
-import android.text.SpannableStringBuilder
 import android.widget.Toast
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent