refactor webrtc video source + capture code

src/main/java/eu/siacs/conversations/xmpp/jingle/TrackWrapper.java

@@ -0,0 +1,31 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+
+import org.webrtc.MediaStreamTrack;
+import org.webrtc.PeerConnection;
+import org.webrtc.RtpSender;
+
+class TrackWrapper<T extends MediaStreamTrack> {
+    private final T track;
+    private final RtpSender rtpSender;
+
+    private TrackWrapper(final T track, final RtpSender rtpSender) {
+        Preconditions.checkNotNull(track);
+        Preconditions.checkNotNull(rtpSender);
+        this.track = track;
+        this.rtpSender = rtpSender;
+    }
+
+    public static <T extends MediaStreamTrack> TrackWrapper<T> addTrack(
+            final PeerConnection peerConnection, final T mediaStreamTrack) {
+        final RtpSender rtpSender = peerConnection.addTrack(mediaStreamTrack);
+        return new TrackWrapper<>(mediaStreamTrack, rtpSender);
+    }
+
+    public static <T extends MediaStreamTrack> Optional<T> get(
+            final TrackWrapper<T> trackWrapper) {
+        return trackWrapper == null ? Optional.absent() : Optional.of(trackWrapper.track);
+    }
+}

src/main/java/eu/siacs/conversations/xmpp/jingle/VideoSourceWrapper.java

@@ -0,0 +1,181 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import android.content.Context;
+import android.util.Log;
+
+import com.google.common.base.Optional;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.SettableFuture;
+
+import org.webrtc.Camera2Enumerator;
+import org.webrtc.CameraEnumerationAndroid;
+import org.webrtc.CameraEnumerator;
+import org.webrtc.CameraVideoCapturer;
+import org.webrtc.EglBase;
+import org.webrtc.PeerConnectionFactory;
+import org.webrtc.SurfaceTextureHelper;
+import org.webrtc.VideoSource;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Set;
+
+import javax.annotation.Nullable;
+
+import eu.siacs.conversations.Config;
+
+class VideoSourceWrapper {
+
+    private static final int CAPTURING_RESOLUTION = 1920;
+    private static final int CAPTURING_MAX_FRAME_RATE = 30;
+
+    private final CameraVideoCapturer cameraVideoCapturer;
+    private final CameraEnumerationAndroid.CaptureFormat captureFormat;
+    private final Set<String> availableCameras;
+    private boolean isFrontCamera = false;
+    private VideoSource videoSource;
+
+    VideoSourceWrapper(
+            CameraVideoCapturer cameraVideoCapturer,
+            CameraEnumerationAndroid.CaptureFormat captureFormat,
+            Set<String> cameras) {
+        this.cameraVideoCapturer = cameraVideoCapturer;
+        this.captureFormat = captureFormat;
+        this.availableCameras = cameras;
+    }
+
+    private int getFrameRate() {
+        return Math.max(
+                captureFormat.framerate.min,
+                Math.min(CAPTURING_MAX_FRAME_RATE, captureFormat.framerate.max));
+    }
+
+    public void initialize(
+            final PeerConnectionFactory peerConnectionFactory,
+            final Context context,
+            final EglBase.Context eglBaseContext) {
+        final SurfaceTextureHelper surfaceTextureHelper =
+                SurfaceTextureHelper.create("webrtc", eglBaseContext);
+        this.videoSource = peerConnectionFactory.createVideoSource(false);
+        this.cameraVideoCapturer.initialize(
+                surfaceTextureHelper, context, this.videoSource.getCapturerObserver());
+    }
+
+    public VideoSource getVideoSource() {
+        final VideoSource videoSource = this.videoSource;
+        if (videoSource == null) {
+            throw new IllegalStateException("VideoSourceWrapper was not initialized");
+        }
+        return videoSource;
+    }
+
+    public void startCapture() {
+        final int frameRate = getFrameRate();
+        Log.d(
+                Config.LOGTAG,
+                String.format(
+                        "start capturing at %dx%d@%d",
+                        captureFormat.width, captureFormat.height, frameRate));
+        this.cameraVideoCapturer.startCapture(captureFormat.width, captureFormat.height, frameRate);
+    }
+
+    public void stopCapture() throws InterruptedException {
+        this.cameraVideoCapturer.stopCapture();
+    }
+
+    public void dispose() {
+        this.cameraVideoCapturer.dispose();
+        if (this.videoSource != null) {
+            this.videoSource.dispose();
+        }
+    }
+
+    public ListenableFuture<Boolean> switchCamera() {
+        final SettableFuture<Boolean> future = SettableFuture.create();
+        this.cameraVideoCapturer.switchCamera(
+                new CameraVideoCapturer.CameraSwitchHandler() {
+                    @Override
+                    public void onCameraSwitchDone(final boolean isFrontCamera) {
+                        VideoSourceWrapper.this.isFrontCamera = isFrontCamera;
+                        future.set(isFrontCamera);
+                    }
+
+                    @Override
+                    public void onCameraSwitchError(final String message) {
+                        future.setException(
+                                new IllegalStateException(
+                                        String.format("Unable to switch camera %s", message)));
+                    }
+                });
+        return future;
+    }
+
+    public boolean isFrontCamera() {
+        return this.isFrontCamera;
+    }
+
+    public boolean isCameraSwitchable() {
+        return this.availableCameras.size() > 1;
+    }
+
+    public static class Factory {
+        final Context context;
+
+        public Factory(final Context context) {
+            this.context = context;
+        }
+
+        public Optional<VideoSourceWrapper> create() {
+            final CameraEnumerator enumerator = new Camera2Enumerator(context);
+            final Set<String> deviceNames = ImmutableSet.copyOf(enumerator.getDeviceNames());
+            for (final String deviceName : deviceNames) {
+                if (isFrontFacing(enumerator, deviceName)) {
+                    final VideoSourceWrapper videoSourceWrapper =
+                            of(enumerator, deviceName, deviceNames);
+                    if (videoSourceWrapper == null) {
+                        return Optional.absent();
+                    }
+                    videoSourceWrapper.isFrontCamera = true;
+                    return Optional.of(videoSourceWrapper);
+                }
+            }
+            if (deviceNames.size() == 0) {
+                return Optional.absent();
+            } else {
+                return Optional.fromNullable(
+                        of(enumerator, Iterables.get(deviceNames, 0), deviceNames));
+            }
+        }
+
+        @Nullable
+        private VideoSourceWrapper of(
+                final CameraEnumerator enumerator,
+                final String deviceName,
+                final Set<String> availableCameras) {
+            final CameraVideoCapturer capturer = enumerator.createCapturer(deviceName, null);
+            if (capturer == null) {
+                return null;
+            }
+            final ArrayList<CameraEnumerationAndroid.CaptureFormat> choices =
+                    new ArrayList<>(enumerator.getSupportedFormats(deviceName));
+            Collections.sort(choices, (a, b) -> b.width - a.width);
+            for (final CameraEnumerationAndroid.CaptureFormat captureFormat : choices) {
+                if (captureFormat.width <= CAPTURING_RESOLUTION) {
+                    return new VideoSourceWrapper(capturer, captureFormat, availableCameras);
+                }
+            }
+            return null;
+        }
+
+        private static boolean isFrontFacing(
+                final CameraEnumerator cameraEnumerator, final String deviceName) {
+            try {
+                return cameraEnumerator.isFrontFacing(deviceName);
+            } catch (final NullPointerException e) {
+                return false;
+            }
+        }
+    }
+}

src/main/java/eu/siacs/conversations/xmpp/jingle/WebRTCWrapper.java

@@ -9,7 +9,6 @@ import android.util.Log;
 import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Iterables;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.MoreExecutors;
@@ -17,10 +16,6 @@ import com.google.common.util.concurrent.SettableFuture;
 
 import org.webrtc.AudioSource;
 import org.webrtc.AudioTrack;
-import org.webrtc.Camera2Enumerator;
-import org.webrtc.CameraEnumerationAndroid;
-import org.webrtc.CameraEnumerator;
-import org.webrtc.CameraVideoCapturer;
 import org.webrtc.CandidatePairChangeEvent;
 import org.webrtc.DataChannel;
 import org.webrtc.DefaultVideoDecoderFactory;
@@ -36,14 +31,10 @@ import org.webrtc.RtpReceiver;
 import org.webrtc.RtpTransceiver;
 import org.webrtc.SdpObserver;
 import org.webrtc.SessionDescription;
-import org.webrtc.SurfaceTextureHelper;
-import org.webrtc.VideoSource;
 import org.webrtc.VideoTrack;
 import org.webrtc.audio.JavaAudioDeviceModule;
 import org.webrtc.voiceengine.WebRtcAudioEffects;
 
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Queue;
@@ -59,13 +50,15 @@ import eu.siacs.conversations.Config;
 import eu.siacs.conversations.services.AppRTCAudioManager;
 import eu.siacs.conversations.services.XmppConnectionService;
 
+@SuppressWarnings("UnstableApiUsage")
 public class WebRTCWrapper {
 
     private static final String EXTENDED_LOGGING_TAG = WebRTCWrapper.class.getSimpleName();
 
     private final ExecutorService executorService = Executors.newSingleThreadExecutor();
 
-    private static final Set<String> HARDWARE_AEC_BLACKLIST = new ImmutableSet.Builder<String>()
+    private static final Set<String> HARDWARE_AEC_BLACKLIST =
+            new ImmutableSet.Builder<String>()
                     .add("Pixel")
                     .add("Pixel XL")
                     .add("Moto G5")
@@ -83,22 +76,24 @@ public class WebRTCWrapper {
                     .add("GT-I9505") // Samsung Galaxy S4 (jfltexx)
                     .build();
 
-    private static final int CAPTURING_RESOLUTION = 1920;
-    private static final int CAPTURING_MAX_FRAME_RATE = 30;
-
     private final EventCallback eventCallback;
     private final AtomicBoolean readyToReceivedIceCandidates = new AtomicBoolean(false);
     private final Queue<IceCandidate> iceCandidates = new LinkedList<>();
-    private final AppRTCAudioManager.AudioManagerEvents audioManagerEvents = new AppRTCAudioManager.AudioManagerEvents() {
+    private final AppRTCAudioManager.AudioManagerEvents audioManagerEvents =
+            new AppRTCAudioManager.AudioManagerEvents() {
                 @Override
-        public void onAudioDeviceChanged(AppRTCAudioManager.AudioDevice selectedAudioDevice, Set<AppRTCAudioManager.AudioDevice> availableAudioDevices) {
+                public void onAudioDeviceChanged(
+                        AppRTCAudioManager.AudioDevice selectedAudioDevice,
+                        Set<AppRTCAudioManager.AudioDevice> availableAudioDevices) {
                     eventCallback.onAudioDeviceChanged(selectedAudioDevice, availableAudioDevices);
                 }
             };
     private final Handler mainHandler = new Handler(Looper.getMainLooper());
-    private VideoTrack localVideoTrack = null;
+    private TrackWrapper<AudioTrack> localAudioTrack = null;
+    private TrackWrapper<VideoTrack> localVideoTrack = null;
     private VideoTrack remoteVideoTrack = null;
-    private final PeerConnection.Observer peerConnectionObserver = new PeerConnection.Observer() {
+    private final PeerConnection.Observer peerConnectionObserver =
+            new PeerConnection.Observer() {
                 @Override
                 public void onSignalingChange(PeerConnection.SignalingState signalingState) {
                     Log.d(EXTENDED_LOGGING_TAG, "onSignalingChange(" + signalingState + ")");
@@ -113,8 +108,11 @@ public class WebRTCWrapper {
                 }
 
                 @Override
-        public void onIceConnectionChange(PeerConnection.IceConnectionState iceConnectionState) {
+                public void onIceConnectionChange(
-            Log.d(EXTENDED_LOGGING_TAG, "onIceConnectionChange(" + iceConnectionState + ")");
+                        PeerConnection.IceConnectionState iceConnectionState) {
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onIceConnectionChange(" + iceConnectionState + ")");
                 }
 
                 @Override
@@ -124,12 +122,11 @@ public class WebRTCWrapper {
                 }
 
                 @Override
-        public void onIceConnectionReceivingChange(boolean b) {
+                public void onIceConnectionReceivingChange(boolean b) {}
-
-        }
 
                 @Override
-        public void onIceGatheringChange(PeerConnection.IceGatheringState iceGatheringState) {
+                public void onIceGatheringChange(
+                        PeerConnection.IceGatheringState iceGatheringState) {
                     Log.d(EXTENDED_LOGGING_TAG, "onIceGatheringChange(" + iceGatheringState + ")");
                 }
 
@@ -143,30 +140,32 @@ public class WebRTCWrapper {
                 }
 
                 @Override
-        public void onIceCandidatesRemoved(IceCandidate[] iceCandidates) {
+                public void onIceCandidatesRemoved(IceCandidate[] iceCandidates) {}
-
-        }
 
                 @Override
                 public void onAddStream(MediaStream mediaStream) {
-            Log.d(EXTENDED_LOGGING_TAG, "onAddStream(numAudioTracks=" + mediaStream.audioTracks.size() + ",numVideoTracks=" + mediaStream.videoTracks.size() + ")");
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onAddStream(numAudioTracks="
+                                    + mediaStream.audioTracks.size()
+                                    + ",numVideoTracks="
+                                    + mediaStream.videoTracks.size()
+                                    + ")");
                 }
 
                 @Override
-        public void onRemoveStream(MediaStream mediaStream) {
+                public void onRemoveStream(MediaStream mediaStream) {}
-
-        }
 
                 @Override
-        public void onDataChannel(DataChannel dataChannel) {
+                public void onDataChannel(DataChannel dataChannel) {}
-
-        }
 
                 @Override
                 public void onRenegotiationNeeded() {
                     Log.d(EXTENDED_LOGGING_TAG, "onRenegotiationNeeded()");
-            final PeerConnection.PeerConnectionState currentState = peerConnection == null ? null : peerConnection.connectionState();
+                    final PeerConnection.PeerConnectionState currentState =
-            if (currentState != null && currentState != PeerConnection.PeerConnectionState.NEW) {
+                            peerConnection == null ? null : peerConnection.connectionState();
+                    if (currentState != null
+                            && currentState != PeerConnection.PeerConnectionState.NEW) {
                         eventCallback.onRenegotiationNeeded();
                     }
                 }
@@ -174,7 +173,13 @@ public class WebRTCWrapper {
                 @Override
                 public void onAddTrack(RtpReceiver rtpReceiver, MediaStream[] mediaStreams) {
                     final MediaStreamTrack track = rtpReceiver.track();
-            Log.d(EXTENDED_LOGGING_TAG, "onAddTrack(kind=" + (track == null ? "null" : track.kind()) + ",numMediaStreams=" + mediaStreams.length + ")");
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onAddTrack(kind="
+                                    + (track == null ? "null" : track.kind())
+                                    + ",numMediaStreams="
+                                    + mediaStreams.length
+                                    + ")");
                     if (track instanceof VideoTrack) {
                         remoteVideoTrack = (VideoTrack) track;
                     }
@@ -182,17 +187,21 @@ public class WebRTCWrapper {
 
                 @Override
                 public void onTrack(RtpTransceiver transceiver) {
-            Log.d(EXTENDED_LOGGING_TAG, "onTrack(mid=" + transceiver.getMid() + ",media=" + transceiver.getMediaType() + ")");
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onTrack(mid="
+                                    + transceiver.getMid()
+                                    + ",media="
+                                    + transceiver.getMediaType()
+                                    + ")");
                 }
             };
-    @Nullable
+    @Nullable private PeerConnection peerConnection = null;
-    private PeerConnection peerConnection = null;
-    private AudioTrack localAudioTrack = null;
     private AppRTCAudioManager appRTCAudioManager = null;
     private ToneManager toneManager = null;
     private Context context = null;
     private EglBase eglBase = null;
-    private CapturerChoice capturerChoice;
+    private VideoSourceWrapper videoSourceWrapper;
 
     WebRTCWrapper(final EventCallback eventCallback) {
         this.eventCallback = eventCallback;
@@ -206,37 +215,15 @@ public class WebRTCWrapper {
         }
     }
 
-    @Nullable
+    public void setup(
-    private static CapturerChoice of(CameraEnumerator enumerator, final String deviceName, Set<String> availableCameras) {
+            final XmppConnectionService service,
-        final CameraVideoCapturer capturer = enumerator.createCapturer(deviceName, null);
+            final AppRTCAudioManager.SpeakerPhonePreference speakerPhonePreference)
-        if (capturer == null) {
+            throws InitializationException {
-            return null;
-        }
-        final ArrayList<CameraEnumerationAndroid.CaptureFormat> choices = new ArrayList<>(enumerator.getSupportedFormats(deviceName));
-        Collections.sort(choices, (a, b) -> b.width - a.width);
-        for (final CameraEnumerationAndroid.CaptureFormat captureFormat : choices) {
-            if (captureFormat.width <= CAPTURING_RESOLUTION) {
-                return new CapturerChoice(capturer, captureFormat, availableCameras);
-            }
-        }
-        return null;
-    }
-
-    private static boolean isFrontFacing(final CameraEnumerator cameraEnumerator, final String deviceName) {
-        try {
-            return cameraEnumerator.isFrontFacing(deviceName);
-        } catch (final NullPointerException e) {
-            return false;
-        }
-    }
-
-    public void setup(final XmppConnectionService service, final AppRTCAudioManager.SpeakerPhonePreference speakerPhonePreference) throws InitializationException {
         try {
             PeerConnectionFactory.initialize(
                     PeerConnectionFactory.InitializationOptions.builder(service)
                             .setFieldTrials("WebRTC-BindUsingInterfaceName/Enabled/")
-                    .createInitializationOptions()
+                            .createInitializationOptions());
-            );
         } catch (final UnsatisfiedLinkError e) {
             throw new InitializationException("Unable to initialize PeerConnectionFactory", e);
         }
@@ -247,68 +234,93 @@ public class WebRTCWrapper {
         }
         this.context = service;
         this.toneManager = service.getJingleConnectionManager().toneManager;
-        mainHandler.post(() -> {
+        mainHandler.post(
+                () -> {
                     appRTCAudioManager = AppRTCAudioManager.create(service, speakerPhonePreference);
                     toneManager.setAppRtcAudioManagerHasControl(true);
                     appRTCAudioManager.start(audioManagerEvents);
-            eventCallback.onAudioDeviceChanged(appRTCAudioManager.getSelectedAudioDevice(), appRTCAudioManager.getAudioDevices());
+                    eventCallback.onAudioDeviceChanged(
+                            appRTCAudioManager.getSelectedAudioDevice(),
+                            appRTCAudioManager.getAudioDevices());
                 });
     }
 
-    synchronized void initializePeerConnection(final Set<Media> media, final List<PeerConnection.IceServer> iceServers) throws InitializationException {
+    synchronized void initializePeerConnection(
+            final Set<Media> media, final List<PeerConnection.IceServer> iceServers)
+            throws InitializationException {
         Preconditions.checkState(this.eglBase != null);
         Preconditions.checkNotNull(media);
-        Preconditions.checkArgument(media.size() > 0, "media can not be empty when initializing peer connection");
+        Preconditions.checkArgument(
-        final boolean setUseHardwareAcousticEchoCanceler = WebRtcAudioEffects.canUseAcousticEchoCanceler() && !HARDWARE_AEC_BLACKLIST.contains(Build.MODEL);
+                media.size() > 0, "media can not be empty when initializing peer connection");
-        Log.d(Config.LOGTAG, String.format("setUseHardwareAcousticEchoCanceler(%s) model=%s", setUseHardwareAcousticEchoCanceler, Build.MODEL));
+        final boolean setUseHardwareAcousticEchoCanceler =
-        PeerConnectionFactory peerConnectionFactory = PeerConnectionFactory.builder()
+                WebRtcAudioEffects.canUseAcousticEchoCanceler()
-                .setVideoDecoderFactory(new DefaultVideoDecoderFactory(eglBase.getEglBaseContext()))
+                        && !HARDWARE_AEC_BLACKLIST.contains(Build.MODEL);
-                .setVideoEncoderFactory(new DefaultVideoEncoderFactory(eglBase.getEglBaseContext(), true, true))
+        Log.d(
-                .setAudioDeviceModule(JavaAudioDeviceModule.builder(context)
+                Config.LOGTAG,
-                        .setUseHardwareAcousticEchoCanceler(setUseHardwareAcousticEchoCanceler)
+                String.format(
-                        .createAudioDeviceModule()
+                        "setUseHardwareAcousticEchoCanceler(%s) model=%s",
-                )
+                        setUseHardwareAcousticEchoCanceler, Build.MODEL));
+        PeerConnectionFactory peerConnectionFactory =
+                PeerConnectionFactory.builder()
+                        .setVideoDecoderFactory(
+                                new DefaultVideoDecoderFactory(eglBase.getEglBaseContext()))
+                        .setVideoEncoderFactory(
+                                new DefaultVideoEncoderFactory(
+                                        eglBase.getEglBaseContext(), true, true))
+                        .setAudioDeviceModule(
+                                JavaAudioDeviceModule.builder(context)
+                                        .setUseHardwareAcousticEchoCanceler(
+                                                setUseHardwareAcousticEchoCanceler)
+                                        .createAudioDeviceModule())
                         .createPeerConnectionFactory();
 
-
         final PeerConnection.RTCConfiguration rtcConfig = buildConfiguration(iceServers);
-        final PeerConnection peerConnection = peerConnectionFactory.createPeerConnection(rtcConfig, peerConnectionObserver);
+        final PeerConnection peerConnection =
+                peerConnectionFactory.createPeerConnection(rtcConfig, peerConnectionObserver);
         if (peerConnection == null) {
             throw new InitializationException("Unable to create PeerConnection");
         }
 
-        final Optional<CapturerChoice> optionalCapturerChoice = media.contains(Media.VIDEO) ? getVideoCapturer() : Optional.absent();
+        final Optional<VideoSourceWrapper> optionalVideoSourceWrapper =
+                media.contains(Media.VIDEO)
+                        ? new VideoSourceWrapper.Factory(requireContext()).create()
+                        : Optional.absent();
 
-        if (optionalCapturerChoice.isPresent()) {
+        if (optionalVideoSourceWrapper.isPresent()) {
-            this.capturerChoice = optionalCapturerChoice.get();
+            this.videoSourceWrapper = optionalVideoSourceWrapper.get();
-            final CameraVideoCapturer capturer = this.capturerChoice.cameraVideoCapturer;
+            this.videoSourceWrapper.initialize(
-            final VideoSource videoSource = peerConnectionFactory.createVideoSource(false);
+                    peerConnectionFactory, context, eglBase.getEglBaseContext());
-            SurfaceTextureHelper surfaceTextureHelper = SurfaceTextureHelper.create("webrtc", eglBase.getEglBaseContext());
+            this.videoSourceWrapper.startCapture();
-            capturer.initialize(surfaceTextureHelper, requireContext(), videoSource.getCapturerObserver());
-            Log.d(Config.LOGTAG, String.format("start capturing at %dx%d@%d", capturerChoice.captureFormat.width, capturerChoice.captureFormat.height, capturerChoice.getFrameRate()));
-            capturer.startCapture(capturerChoice.captureFormat.width, capturerChoice.captureFormat.height, capturerChoice.getFrameRate());
 
-            this.localVideoTrack = peerConnectionFactory.createVideoTrack("my-video-track", videoSource);
+            final VideoTrack videoTrack =
+                    peerConnectionFactory.createVideoTrack(
+                            "my-video-track", this.videoSourceWrapper.getVideoSource());
 
-            peerConnection.addTrack(this.localVideoTrack);
+            this.localVideoTrack = TrackWrapper.addTrack(peerConnection, videoTrack);
         }
 
-
         if (media.contains(Media.AUDIO)) {
             // set up audio track
-            final AudioSource audioSource = peerConnectionFactory.createAudioSource(new MediaConstraints());
+            final AudioSource audioSource =
-            this.localAudioTrack = peerConnectionFactory.createAudioTrack("my-audio-track", audioSource);
+                    peerConnectionFactory.createAudioSource(new MediaConstraints());
-            peerConnection.addTrack(this.localAudioTrack);
+            final AudioTrack audioTrack =
+                    peerConnectionFactory.createAudioTrack("my-audio-track", audioSource);
+            this.localAudioTrack = TrackWrapper.addTrack(peerConnection, audioTrack);
         }
         peerConnection.setAudioPlayout(true);
         peerConnection.setAudioRecording(true);
+
         this.peerConnection = peerConnection;
     }
 
-    private static PeerConnection.RTCConfiguration buildConfiguration(final List<PeerConnection.IceServer> iceServers) {
+    private static PeerConnection.RTCConfiguration buildConfiguration(
-        final PeerConnection.RTCConfiguration rtcConfig = new PeerConnection.RTCConfiguration(iceServers);
+            final List<PeerConnection.IceServer> iceServers) {
-        rtcConfig.tcpCandidatePolicy = PeerConnection.TcpCandidatePolicy.DISABLED; //XEP-0176 doesn't support tcp
+        final PeerConnection.RTCConfiguration rtcConfig =
-        rtcConfig.continualGatheringPolicy = PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY;
+                new PeerConnection.RTCConfiguration(iceServers);
+        rtcConfig.tcpCandidatePolicy =
+                PeerConnection.TcpCandidatePolicy.DISABLED; // XEP-0176 doesn't support tcp
+        rtcConfig.continualGatheringPolicy =
+                PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY;
         rtcConfig.sdpSemantics = PeerConnection.SdpSemantics.UNIFIED_PLAN;
         rtcConfig.rtcpMuxPolicy = PeerConnection.RtcpMuxPolicy.NEGOTIATE;
         rtcConfig.enableImplicitRollback = true;
@@ -332,7 +344,7 @@ public class WebRTCWrapper {
 
     synchronized void close() {
         final PeerConnection peerConnection = this.peerConnection;
-        final CapturerChoice capturerChoice = this.capturerChoice;
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
         final AppRTCAudioManager audioManager = this.appRTCAudioManager;
         final EglBase eglBase = this.eglBase;
         if (peerConnection != null) {
@@ -345,12 +357,13 @@ public class WebRTCWrapper {
         }
         this.localVideoTrack = null;
         this.remoteVideoTrack = null;
-        if (capturerChoice != null) {
+        if (videoSourceWrapper != null) {
             try {
-                capturerChoice.cameraVideoCapturer.stopCapture();
+                videoSourceWrapper.stopCapture();
-            } catch (InterruptedException e) {
+            } catch (final InterruptedException e) {
                 Log.e(Config.LOGTAG, "unable to stop capturing");
             }
+            // TODO call dispose
         }
         if (eglBase != null) {
             eglBase.release();
@@ -363,94 +376,95 @@ public class WebRTCWrapper {
                 || this.eglBase != null
                 || this.localVideoTrack != null
                 || this.remoteVideoTrack != null) {
-            final IllegalStateException e = new IllegalStateException("WebRTCWrapper hasn't been closed properly");
+            final IllegalStateException e =
+                    new IllegalStateException("WebRTCWrapper hasn't been closed properly");
             Log.e(Config.LOGTAG, "verifyClosed() failed. Going to throw", e);
             throw e;
         }
     }
 
     boolean isCameraSwitchable() {
-        final CapturerChoice capturerChoice = this.capturerChoice;
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
-        return capturerChoice != null && capturerChoice.availableCameras.size() > 1;
+        return videoSourceWrapper != null && videoSourceWrapper.isCameraSwitchable();
     }
 
     boolean isFrontCamera() {
-        final CapturerChoice capturerChoice = this.capturerChoice;
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
-        return capturerChoice == null || capturerChoice.isFrontCamera;
+        return videoSourceWrapper == null || videoSourceWrapper.isFrontCamera();
     }
 
     ListenableFuture<Boolean> switchCamera() {
-        final CapturerChoice capturerChoice = this.capturerChoice;
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
-        if (capturerChoice == null) {
+        if (videoSourceWrapper == null) {
-            return Futures.immediateFailedFuture(new IllegalStateException("CameraCapturer has not been initialized"));
+            return Futures.immediateFailedFuture(
+                    new IllegalStateException("VideoSourceWrapper has not been initialized"));
         }
-        final SettableFuture<Boolean> future = SettableFuture.create();
+        return videoSourceWrapper.switchCamera();
-        capturerChoice.cameraVideoCapturer.switchCamera(new CameraVideoCapturer.CameraSwitchHandler() {
-            @Override
-            public void onCameraSwitchDone(boolean isFrontCamera) {
-                capturerChoice.isFrontCamera = isFrontCamera;
-                future.set(isFrontCamera);
-            }
-
-            @Override
-            public void onCameraSwitchError(final String message) {
-                future.setException(new IllegalStateException(String.format("Unable to switch camera %s", message)));
-            }
-        });
-        return future;
     }
 
     boolean isMicrophoneEnabled() {
-        final AudioTrack audioTrack = this.localAudioTrack;
+        final Optional<AudioTrack> audioTrack = TrackWrapper.get(this.localAudioTrack);
-        if (audioTrack == null) {
+        if (audioTrack.isPresent()) {
-            throw new IllegalStateException("Local audio track does not exist (yet)");
-        }
             try {
-            return audioTrack.enabled();
+                return audioTrack.get().enabled();
             } catch (final IllegalStateException e) {
-            //sometimes UI might still be rendering the buttons when a background thread has already ended the call
+                // sometimes UI might still be rendering the buttons when a background thread has
+                // already ended the call
                 return false;
             }
+        } else {
+            throw new IllegalStateException("Local audio track does not exist (yet)");
+        }
     }
 
     boolean setMicrophoneEnabled(final boolean enabled) {
-        final AudioTrack audioTrack = this.localAudioTrack;
+        final Optional<AudioTrack> audioTrack = TrackWrapper.get(this.localAudioTrack);
-        if (audioTrack == null) {
+        if (audioTrack.isPresent()) {
-            throw new IllegalStateException("Local audio track does not exist (yet)");
-        }
             try {
-            audioTrack.setEnabled(enabled);
+                audioTrack.get().setEnabled(enabled);
                 return true;
             } catch (final IllegalStateException e) {
                 Log.d(Config.LOGTAG, "unable to toggle microphone", e);
                 // ignoring race condition in case MediaStreamTrack has been disposed
                 return false;
             }
+        } else {
+            throw new IllegalStateException("Local audio track does not exist (yet)");
+        }
     }
 
     boolean isVideoEnabled() {
-        final VideoTrack videoTrack = this.localVideoTrack;
+        final Optional<VideoTrack> videoTrack = TrackWrapper.get(this.localVideoTrack);
-        if (videoTrack == null) {
+        if (videoTrack.isPresent()) {
-            return false;
+            return videoTrack.get().enabled();
         }
-        return videoTrack.enabled();
+        return false;
     }
 
     void setVideoEnabled(final boolean enabled) {
-        final VideoTrack videoTrack = this.localVideoTrack;
+        final Optional<VideoTrack> videoTrack = TrackWrapper.get(this.localVideoTrack);
-        if (videoTrack == null) {
+        if (videoTrack.isPresent()) {
-            throw new IllegalStateException("Local video track does not exist");
+            videoTrack.get().setEnabled(enabled);
+            return;
         }
-        videoTrack.setEnabled(enabled);
+        throw new IllegalStateException("Local video track does not exist");
     }
 
     synchronized ListenableFuture<SessionDescription> setLocalDescription() {
-        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
+        return Futures.transformAsync(
+                getPeerConnectionFuture(),
+                peerConnection -> {
+                    if (peerConnection == null) {
+                        return Futures.immediateFailedFuture(
+                                new IllegalStateException("PeerConnection was null"));
+                    }
                     final SettableFuture<SessionDescription> future = SettableFuture.create();
-            peerConnection.setLocalDescription(new SetSdpObserver() {
+                    peerConnection.setLocalDescription(
+                            new SetSdpObserver() {
                                 @Override
                                 public void onSetSuccess() {
-                    final SessionDescription description = peerConnection.getLocalDescription();
+                                    final SessionDescription description =
+                                            peerConnection.getLocalDescription();
                                     Log.d(EXTENDED_LOGGING_TAG, "set local description:");
                                     logDescription(description);
                                     future.set(description);
@@ -458,25 +472,37 @@ public class WebRTCWrapper {
 
                                 @Override
                                 public void onSetFailure(final String message) {
-                    future.setException(new FailureToSetDescriptionException(message));
+                                    future.setException(
+                                            new FailureToSetDescriptionException(message));
                                 }
                             });
                     return future;
-        }, MoreExecutors.directExecutor());
+                },
+                MoreExecutors.directExecutor());
     }
 
     private static void logDescription(final SessionDescription sessionDescription) {
-        for (final String line : sessionDescription.description.split(eu.siacs.conversations.xmpp.jingle.SessionDescription.LINE_DIVIDER)) {
+        for (final String line :
+                sessionDescription.description.split(
+                        eu.siacs.conversations.xmpp.jingle.SessionDescription.LINE_DIVIDER)) {
             Log.d(EXTENDED_LOGGING_TAG, line);
         }
     }
 
-    synchronized ListenableFuture<Void> setRemoteDescription(final SessionDescription sessionDescription) {
+    synchronized ListenableFuture<Void> setRemoteDescription(
+            final SessionDescription sessionDescription) {
         Log.d(EXTENDED_LOGGING_TAG, "setting remote description:");
         logDescription(sessionDescription);
-        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
+        return Futures.transformAsync(
+                getPeerConnectionFuture(),
+                peerConnection -> {
+                    if (peerConnection == null) {
+                        return Futures.immediateFailedFuture(
+                                new IllegalStateException("PeerConnection was null"));
+                    }
                     final SettableFuture<Void> future = SettableFuture.create();
-            peerConnection.setRemoteDescription(new SetSdpObserver() {
+                    peerConnection.setRemoteDescription(
+                            new SetSdpObserver() {
                                 @Override
                                 public void onSetSuccess() {
                                     future.set(null);
@@ -484,11 +510,14 @@ public class WebRTCWrapper {
 
                                 @Override
                                 public void onSetFailure(final String message) {
-                    future.setException(new FailureToSetDescriptionException(message));
+                                    future.setException(
+                                            new FailureToSetDescriptionException(message));
                                 }
-            }, sessionDescription);
+                            },
+                            sessionDescription);
                     return future;
-        }, MoreExecutors.directExecutor());
+                },
+                MoreExecutors.directExecutor());
     }
 
     @Nonnull
@@ -513,26 +542,6 @@ public class WebRTCWrapper {
         requirePeerConnection().addIceCandidate(iceCandidate);
     }
 
-    private Optional<CapturerChoice> getVideoCapturer() {
-        final CameraEnumerator enumerator = new Camera2Enumerator(requireContext());
-        final Set<String> deviceNames = ImmutableSet.copyOf(enumerator.getDeviceNames());
-        for (final String deviceName : deviceNames) {
-            if (isFrontFacing(enumerator, deviceName)) {
-                final CapturerChoice capturerChoice = of(enumerator, deviceName, deviceNames);
-                if (capturerChoice == null) {
-                    return Optional.absent();
-                }
-                capturerChoice.isFrontCamera = true;
-                return Optional.of(capturerChoice);
-            }
-        }
-        if (deviceNames.size() == 0) {
-            return Optional.absent();
-        } else {
-            return Optional.fromNullable(of(enumerator, Iterables.get(deviceNames, 0), deviceNames));
-        }
-    }
-
     PeerConnection.PeerConnectionState getState() {
         return requirePeerConnection().connectionState();
     }
@@ -541,13 +550,12 @@ public class WebRTCWrapper {
         return requirePeerConnection().signalingState();
     }
 
-
     EglBase.Context getEglBaseContext() {
         return this.eglBase.getEglBaseContext();
     }
 
     Optional<VideoTrack> getLocalVideoTrack() {
-        return Optional.fromNullable(this.localVideoTrack);
+        return TrackWrapper.get(this.localVideoTrack);
     }
 
     Optional<VideoTrack> getRemoteVideoTrack() {
@@ -575,12 +583,14 @@ public class WebRTCWrapper {
 
         void onConnectionChange(PeerConnection.PeerConnectionState newState);
 
-        void onAudioDeviceChanged(AppRTCAudioManager.AudioDevice selectedAudioDevice, Set<AppRTCAudioManager.AudioDevice> availableAudioDevices);
+        void onAudioDeviceChanged(
+                AppRTCAudioManager.AudioDevice selectedAudioDevice,
+                Set<AppRTCAudioManager.AudioDevice> availableAudioDevices);
 
         void onRenegotiationNeeded();
     }
 
-    private static abstract class SetSdpObserver implements SdpObserver {
+    private abstract static class SetSdpObserver implements SdpObserver {
 
         @Override
         public void onCreateSuccess(org.webrtc.SessionDescription sessionDescription) {
@@ -591,22 +601,6 @@ public class WebRTCWrapper {
         public void onCreateFailure(String s) {
             throw new IllegalStateException("Not able to use SetSdpObserver");
         }
-
-    }
-
-    private static abstract class CreateSdpObserver implements SdpObserver {
-
-
-        @Override
-        public void onSetSuccess() {
-            throw new IllegalStateException("Not able to use CreateSdpObserver");
-        }
-
-
-        @Override
-        public void onSetFailure(String s) {
-            throw new IllegalStateException("Not able to use CreateSdpObserver");
-        }
     }
 
     static class InitializationException extends Exception {
@@ -625,7 +619,6 @@ public class WebRTCWrapper {
         private PeerConnectionNotInitialized() {
             super("initialize PeerConnection first");
         }
-
     }
 
     private static class FailureToSetDescriptionException extends IllegalArgumentException {
@@ -634,20 +627,4 @@ public class WebRTCWrapper {
         }
     }
 
-    private static class CapturerChoice {
-        private final CameraVideoCapturer cameraVideoCapturer;
-        private final CameraEnumerationAndroid.CaptureFormat captureFormat;
-        private final Set<String> availableCameras;
-        private boolean isFrontCamera = false;
-
-        CapturerChoice(CameraVideoCapturer cameraVideoCapturer, CameraEnumerationAndroid.CaptureFormat captureFormat, Set<String> cameras) {
-            this.cameraVideoCapturer = cameraVideoCapturer;
-            this.captureFormat = captureFormat;
-            this.availableCameras = cameras;
-        }
-
-        int getFrameRate() {
-            return Math.max(captureFormat.framerate.min, Math.min(CAPTURING_MAX_FRAME_RATE, captureFormat.framerate.max));
-        }
-    }
 }