WebRTCWrapper.java

  1package eu.siacs.conversations.xmpp.jingle;
  2
  3import android.content.Context;
  4import android.os.Build;
  5import android.os.Handler;
  6import android.os.Looper;
  7import android.util.Log;
  8
  9import com.google.common.base.Optional;
 10import com.google.common.base.Preconditions;
 11import com.google.common.collect.ImmutableSet;
 12import com.google.common.collect.Iterables;
 13import com.google.common.util.concurrent.Futures;
 14import com.google.common.util.concurrent.ListenableFuture;
 15import com.google.common.util.concurrent.MoreExecutors;
 16import com.google.common.util.concurrent.SettableFuture;
 17
 18import org.webrtc.AudioSource;
 19import org.webrtc.AudioTrack;
 20import org.webrtc.Camera1Enumerator;
 21import org.webrtc.Camera2Enumerator;
 22import org.webrtc.CameraEnumerationAndroid;
 23import org.webrtc.CameraEnumerator;
 24import org.webrtc.CameraVideoCapturer;
 25import org.webrtc.CandidatePairChangeEvent;
 26import org.webrtc.DataChannel;
 27import org.webrtc.DefaultVideoDecoderFactory;
 28import org.webrtc.DefaultVideoEncoderFactory;
 29import org.webrtc.EglBase;
 30import org.webrtc.IceCandidate;
 31import org.webrtc.MediaConstraints;
 32import org.webrtc.MediaStream;
 33import org.webrtc.MediaStreamTrack;
 34import org.webrtc.PeerConnection;
 35import org.webrtc.PeerConnectionFactory;
 36import org.webrtc.RtpReceiver;
 37import org.webrtc.RtpTransceiver;
 38import org.webrtc.SdpObserver;
 39import org.webrtc.SessionDescription;
 40import org.webrtc.SurfaceTextureHelper;
 41import org.webrtc.VideoSource;
 42import org.webrtc.VideoTrack;
 43import org.webrtc.audio.JavaAudioDeviceModule;
 44import org.webrtc.voiceengine.WebRtcAudioEffects;
 45
 46import java.util.ArrayList;
 47import java.util.Collections;
 48import java.util.List;
 49import java.util.Set;
 50
 51import javax.annotation.Nonnull;
 52import javax.annotation.Nullable;
 53
 54import eu.siacs.conversations.Config;
 55import eu.siacs.conversations.services.AppRTCAudioManager;
 56import eu.siacs.conversations.services.XmppConnectionService;
 57
 58public class WebRTCWrapper {
 59
 60    private static final String EXTENDED_LOGGING_TAG = WebRTCWrapper.class.getSimpleName();
 61
 62    //we should probably keep this in sync with: https://github.com/signalapp/Signal-Android/blob/master/app/src/main/java/org/thoughtcrime/securesms/ApplicationContext.java#L296
 63    private static final Set<String> HARDWARE_AEC_BLACKLIST = new ImmutableSet.Builder<String>()
 64            .add("Pixel")
 65            .add("Pixel XL")
 66            .add("Moto G5")
 67            .add("Moto G (5S) Plus")
 68            .add("Moto G4")
 69            .add("TA-1053")
 70            .add("Mi A1")
 71            .add("Mi A2")
 72            .add("E5823") // Sony z5 compact
 73            .add("Redmi Note 5")
 74            .add("FP2") // Fairphone FP2
 75            .add("MI 5")
 76            .build();
 77
 78    private static final int CAPTURING_RESOLUTION = 1920;
 79    private static final int CAPTURING_MAX_FRAME_RATE = 30;
 80
 81    private final EventCallback eventCallback;
 82    private final AppRTCAudioManager.AudioManagerEvents audioManagerEvents = new AppRTCAudioManager.AudioManagerEvents() {
 83        @Override
 84        public void onAudioDeviceChanged(AppRTCAudioManager.AudioDevice selectedAudioDevice, Set<AppRTCAudioManager.AudioDevice> availableAudioDevices) {
 85            eventCallback.onAudioDeviceChanged(selectedAudioDevice, availableAudioDevices);
 86        }
 87    };
 88    private final Handler mainHandler = new Handler(Looper.getMainLooper());
 89    private VideoTrack localVideoTrack = null;
 90    private VideoTrack remoteVideoTrack = null;
 91    private final PeerConnection.Observer peerConnectionObserver = new PeerConnection.Observer() {
 92        @Override
 93        public void onSignalingChange(PeerConnection.SignalingState signalingState) {
 94            Log.d(EXTENDED_LOGGING_TAG, "onSignalingChange(" + signalingState + ")");
 95            //this is called after removeTrack or addTrack
 96            //and should then trigger a content-add or content-remove or something
 97            //https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/removeTrack
 98        }
 99
100        @Override
101        public void onConnectionChange(PeerConnection.PeerConnectionState newState) {
102            eventCallback.onConnectionChange(newState);
103        }
104
105        @Override
106        public void onIceConnectionChange(PeerConnection.IceConnectionState iceConnectionState) {
107
108        }
109
110        @Override
111        public void onSelectedCandidatePairChanged(CandidatePairChangeEvent event) {
112            Log.d(Config.LOGTAG, "remote candidate selected: " + event.remote);
113            Log.d(Config.LOGTAG, "local candidate selected: " + event.local);
114        }
115
116        @Override
117        public void onIceConnectionReceivingChange(boolean b) {
118
119        }
120
121        @Override
122        public void onIceGatheringChange(PeerConnection.IceGatheringState iceGatheringState) {
123            Log.d(EXTENDED_LOGGING_TAG, "onIceGatheringChange(" + iceGatheringState + ")");
124        }
125
126        @Override
127        public void onIceCandidate(IceCandidate iceCandidate) {
128            eventCallback.onIceCandidate(iceCandidate);
129        }
130
131        @Override
132        public void onIceCandidatesRemoved(IceCandidate[] iceCandidates) {
133
134        }
135
136        @Override
137        public void onAddStream(MediaStream mediaStream) {
138            Log.d(EXTENDED_LOGGING_TAG, "onAddStream(numAudioTracks=" + mediaStream.audioTracks.size() + ",numVideoTracks=" + mediaStream.videoTracks.size() + ")");
139            final List<VideoTrack> videoTracks = mediaStream.videoTracks;
140            if (videoTracks.size() > 0) {
141                remoteVideoTrack = videoTracks.get(0);
142                Log.d(Config.LOGTAG, "remote video track enabled?=" + remoteVideoTrack.enabled());
143            } else {
144                Log.d(Config.LOGTAG, "no remote video tracks found");
145            }
146        }
147
148        @Override
149        public void onRemoveStream(MediaStream mediaStream) {
150
151        }
152
153        @Override
154        public void onDataChannel(DataChannel dataChannel) {
155
156        }
157
158        @Override
159        public void onRenegotiationNeeded() {
160
161        }
162
163        @Override
164        public void onAddTrack(RtpReceiver rtpReceiver, MediaStream[] mediaStreams) {
165            final MediaStreamTrack track = rtpReceiver.track();
166            Log.d(EXTENDED_LOGGING_TAG, "onAddTrack(kind=" + (track == null ? "null" : track.kind()) + ",numMediaStreams=" + mediaStreams.length + ")");
167        }
168
169        @Override
170        public void onTrack(RtpTransceiver transceiver) {
171            Log.d(EXTENDED_LOGGING_TAG, "onTrack(mid=" + transceiver.getMid() + ",media=" + transceiver.getMediaType() + ")");
172        }
173    };
174    @Nullable
175    private PeerConnection peerConnection = null;
176    private AudioTrack localAudioTrack = null;
177    private AppRTCAudioManager appRTCAudioManager = null;
178    private ToneManager toneManager = null;
179    private Context context = null;
180    private EglBase eglBase = null;
181    private CapturerChoice capturerChoice;
182
183    WebRTCWrapper(final EventCallback eventCallback) {
184        this.eventCallback = eventCallback;
185    }
186
187    private static void dispose(final PeerConnection peerConnection) {
188        try {
189            peerConnection.dispose();
190        } catch (final IllegalStateException e) {
191            Log.e(Config.LOGTAG, "unable to dispose of peer connection", e);
192        }
193    }
194
195    @Nullable
196    private static CapturerChoice of(CameraEnumerator enumerator, final String deviceName, Set<String> availableCameras) {
197        final CameraVideoCapturer capturer = enumerator.createCapturer(deviceName, null);
198        if (capturer == null) {
199            return null;
200        }
201        final ArrayList<CameraEnumerationAndroid.CaptureFormat> choices = new ArrayList<>(enumerator.getSupportedFormats(deviceName));
202        Collections.sort(choices, (a, b) -> b.width - a.width);
203        for (final CameraEnumerationAndroid.CaptureFormat captureFormat : choices) {
204            if (captureFormat.width <= CAPTURING_RESOLUTION) {
205                return new CapturerChoice(capturer, captureFormat, availableCameras);
206            }
207        }
208        return null;
209    }
210
211    public void setup(final XmppConnectionService service, final AppRTCAudioManager.SpeakerPhonePreference speakerPhonePreference) throws InitializationException {
212        try {
213            PeerConnectionFactory.initialize(
214                    PeerConnectionFactory.InitializationOptions.builder(service).createInitializationOptions()
215            );
216        } catch (final UnsatisfiedLinkError e) {
217            throw new InitializationException(e);
218        }
219        this.eglBase = EglBase.create();
220        this.context = service;
221        this.toneManager = service.getJingleConnectionManager().toneManager;
222        mainHandler.post(() -> {
223            appRTCAudioManager = AppRTCAudioManager.create(service, speakerPhonePreference);
224            toneManager.setAppRtcAudioManagerHasControl(true);
225            appRTCAudioManager.start(audioManagerEvents);
226            eventCallback.onAudioDeviceChanged(appRTCAudioManager.getSelectedAudioDevice(), appRTCAudioManager.getAudioDevices());
227        });
228    }
229
230    synchronized void initializePeerConnection(final Set<Media> media, final List<PeerConnection.IceServer> iceServers) throws InitializationException {
231        Preconditions.checkState(this.eglBase != null);
232        Preconditions.checkNotNull(media);
233        Preconditions.checkArgument(media.size() > 0, "media can not be empty when initializing peer connection");
234        final boolean setUseHardwareAcousticEchoCanceler = WebRtcAudioEffects.canUseAcousticEchoCanceler() && !HARDWARE_AEC_BLACKLIST.contains(Build.MODEL);
235        Log.d(Config.LOGTAG, String.format("setUseHardwareAcousticEchoCanceler(%s) model=%s", setUseHardwareAcousticEchoCanceler, Build.MODEL));
236        PeerConnectionFactory peerConnectionFactory = PeerConnectionFactory.builder()
237                .setVideoDecoderFactory(new DefaultVideoDecoderFactory(eglBase.getEglBaseContext()))
238                .setVideoEncoderFactory(new DefaultVideoEncoderFactory(eglBase.getEglBaseContext(), true, true))
239                .setAudioDeviceModule(JavaAudioDeviceModule.builder(context)
240                        .setUseHardwareAcousticEchoCanceler(setUseHardwareAcousticEchoCanceler)
241                        .createAudioDeviceModule()
242                )
243                .createPeerConnectionFactory();
244
245
246        final MediaStream stream = peerConnectionFactory.createLocalMediaStream("my-media-stream");
247
248        final Optional<CapturerChoice> optionalCapturerChoice = media.contains(Media.VIDEO) ? getVideoCapturer() : Optional.absent();
249
250        if (optionalCapturerChoice.isPresent()) {
251            this.capturerChoice = optionalCapturerChoice.get();
252            final CameraVideoCapturer capturer = this.capturerChoice.cameraVideoCapturer;
253            final VideoSource videoSource = peerConnectionFactory.createVideoSource(false);
254            SurfaceTextureHelper surfaceTextureHelper = SurfaceTextureHelper.create("webrtc", eglBase.getEglBaseContext());
255            capturer.initialize(surfaceTextureHelper, requireContext(), videoSource.getCapturerObserver());
256            Log.d(Config.LOGTAG, String.format("start capturing at %dx%d@%d", capturerChoice.captureFormat.width, capturerChoice.captureFormat.height, capturerChoice.getFrameRate()));
257            capturer.startCapture(capturerChoice.captureFormat.width, capturerChoice.captureFormat.height, capturerChoice.getFrameRate());
258
259            this.localVideoTrack = peerConnectionFactory.createVideoTrack("my-video-track", videoSource);
260
261            stream.addTrack(this.localVideoTrack);
262        }
263
264
265        if (media.contains(Media.AUDIO)) {
266            //set up audio track
267            final AudioSource audioSource = peerConnectionFactory.createAudioSource(new MediaConstraints());
268            this.localAudioTrack = peerConnectionFactory.createAudioTrack("my-audio-track", audioSource);
269            stream.addTrack(this.localAudioTrack);
270        }
271
272
273        final PeerConnection.RTCConfiguration rtcConfig = new PeerConnection.RTCConfiguration(iceServers);
274        rtcConfig.tcpCandidatePolicy = PeerConnection.TcpCandidatePolicy.DISABLED; //XEP-0176 doesn't support tcp
275        rtcConfig.continualGatheringPolicy = PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY;
276        final PeerConnection peerConnection = peerConnectionFactory.createPeerConnection(rtcConfig, peerConnectionObserver);
277        if (peerConnection == null) {
278            throw new InitializationException("Unable to create PeerConnection");
279        }
280        peerConnection.addStream(stream);
281        peerConnection.setAudioPlayout(true);
282        peerConnection.setAudioRecording(true);
283        this.peerConnection = peerConnection;
284    }
285
286    synchronized void close() {
287        final PeerConnection peerConnection = this.peerConnection;
288        final CapturerChoice capturerChoice = this.capturerChoice;
289        final AppRTCAudioManager audioManager = this.appRTCAudioManager;
290        final EglBase eglBase = this.eglBase;
291        if (peerConnection != null) {
292            dispose(peerConnection);
293            this.peerConnection = null;
294        }
295        if (audioManager != null) {
296            toneManager.setAppRtcAudioManagerHasControl(false);
297            mainHandler.post(audioManager::stop);
298        }
299        this.localVideoTrack = null;
300        this.remoteVideoTrack = null;
301        if (capturerChoice != null) {
302            try {
303                capturerChoice.cameraVideoCapturer.stopCapture();
304            } catch (InterruptedException e) {
305                Log.e(Config.LOGTAG, "unable to stop capturing");
306            }
307        }
308        if (eglBase != null) {
309            eglBase.release();
310            this.eglBase = null;
311        }
312    }
313
314    synchronized void verifyClosed() {
315        if (this.peerConnection != null
316                || this.eglBase != null
317                || this.localVideoTrack != null
318                || this.remoteVideoTrack != null) {
319            final IllegalStateException e = new IllegalStateException("WebRTCWrapper hasn't been closed properly");
320            Log.e(Config.LOGTAG, "verifyClosed() failed. Going to throw", e);
321            throw e;
322        }
323    }
324
325    boolean isCameraSwitchable() {
326        final CapturerChoice capturerChoice = this.capturerChoice;
327        return capturerChoice != null && capturerChoice.availableCameras.size() > 1;
328    }
329
330    boolean isFrontCamera() {
331        final CapturerChoice capturerChoice = this.capturerChoice;
332        return capturerChoice == null || capturerChoice.isFrontCamera;
333    }
334
335    ListenableFuture<Boolean> switchCamera() {
336        final CapturerChoice capturerChoice = this.capturerChoice;
337        if (capturerChoice == null) {
338            return Futures.immediateFailedFuture(new IllegalStateException("CameraCapturer has not been initialized"));
339        }
340        final SettableFuture<Boolean> future = SettableFuture.create();
341        capturerChoice.cameraVideoCapturer.switchCamera(new CameraVideoCapturer.CameraSwitchHandler() {
342            @Override
343            public void onCameraSwitchDone(boolean isFrontCamera) {
344                capturerChoice.isFrontCamera = isFrontCamera;
345                future.set(isFrontCamera);
346            }
347
348            @Override
349            public void onCameraSwitchError(final String message) {
350                future.setException(new IllegalStateException(String.format("Unable to switch camera %s", message)));
351            }
352        });
353        return future;
354    }
355
356    boolean isMicrophoneEnabled() {
357        final AudioTrack audioTrack = this.localAudioTrack;
358        if (audioTrack == null) {
359            throw new IllegalStateException("Local audio track does not exist (yet)");
360        }
361        try {
362            return audioTrack.enabled();
363        } catch (final IllegalStateException e) {
364            //sometimes UI might still be rendering the buttons when a background thread has already ended the call
365            return false;
366        }
367    }
368
369    void setMicrophoneEnabled(final boolean enabled) {
370        final AudioTrack audioTrack = this.localAudioTrack;
371        if (audioTrack == null) {
372            throw new IllegalStateException("Local audio track does not exist (yet)");
373        }
374        audioTrack.setEnabled(enabled);
375    }
376
377    boolean isVideoEnabled() {
378        final VideoTrack videoTrack = this.localVideoTrack;
379        if (videoTrack == null) {
380            throw new IllegalStateException("Local video track does not exist");
381        }
382        return videoTrack.enabled();
383    }
384
385    void setVideoEnabled(final boolean enabled) {
386        final VideoTrack videoTrack = this.localVideoTrack;
387        if (videoTrack == null) {
388            throw new IllegalStateException("Local video track does not exist");
389        }
390        videoTrack.setEnabled(enabled);
391    }
392
393    ListenableFuture<SessionDescription> createOffer() {
394        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
395            final SettableFuture<SessionDescription> future = SettableFuture.create();
396            peerConnection.createOffer(new CreateSdpObserver() {
397                @Override
398                public void onCreateSuccess(SessionDescription sessionDescription) {
399                    future.set(sessionDescription);
400                }
401
402                @Override
403                public void onCreateFailure(String s) {
404                    future.setException(new IllegalStateException("Unable to create offer: " + s));
405                }
406            }, new MediaConstraints());
407            return future;
408        }, MoreExecutors.directExecutor());
409    }
410
411    ListenableFuture<SessionDescription> createAnswer() {
412        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
413            final SettableFuture<SessionDescription> future = SettableFuture.create();
414            peerConnection.createAnswer(new CreateSdpObserver() {
415                @Override
416                public void onCreateSuccess(SessionDescription sessionDescription) {
417                    future.set(sessionDescription);
418                }
419
420                @Override
421                public void onCreateFailure(String s) {
422                    future.setException(new IllegalStateException("Unable to create answer: " + s));
423                }
424            }, new MediaConstraints());
425            return future;
426        }, MoreExecutors.directExecutor());
427    }
428
429    ListenableFuture<Void> setLocalDescription(final SessionDescription sessionDescription) {
430        Log.d(EXTENDED_LOGGING_TAG, "setting local description:");
431        for (final String line : sessionDescription.description.split(eu.siacs.conversations.xmpp.jingle.SessionDescription.LINE_DIVIDER)) {
432            Log.d(EXTENDED_LOGGING_TAG, line);
433        }
434        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
435            final SettableFuture<Void> future = SettableFuture.create();
436            peerConnection.setLocalDescription(new SetSdpObserver() {
437                @Override
438                public void onSetSuccess() {
439                    future.set(null);
440                }
441
442                @Override
443                public void onSetFailure(final String s) {
444                    future.setException(new IllegalArgumentException("unable to set local session description: " + s));
445
446                }
447            }, sessionDescription);
448            return future;
449        }, MoreExecutors.directExecutor());
450    }
451
452    ListenableFuture<Void> setRemoteDescription(final SessionDescription sessionDescription) {
453        Log.d(EXTENDED_LOGGING_TAG, "setting remote description:");
454        for (final String line : sessionDescription.description.split(eu.siacs.conversations.xmpp.jingle.SessionDescription.LINE_DIVIDER)) {
455            Log.d(EXTENDED_LOGGING_TAG, line);
456        }
457        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
458            final SettableFuture<Void> future = SettableFuture.create();
459            peerConnection.setRemoteDescription(new SetSdpObserver() {
460                @Override
461                public void onSetSuccess() {
462                    future.set(null);
463                }
464
465                @Override
466                public void onSetFailure(String s) {
467                    future.setException(new IllegalArgumentException("unable to set remote session description: " + s));
468
469                }
470            }, sessionDescription);
471            return future;
472        }, MoreExecutors.directExecutor());
473    }
474
475    @Nonnull
476    private ListenableFuture<PeerConnection> getPeerConnectionFuture() {
477        final PeerConnection peerConnection = this.peerConnection;
478        if (peerConnection == null) {
479            return Futures.immediateFailedFuture(new IllegalStateException("initialize PeerConnection first"));
480        } else {
481            return Futures.immediateFuture(peerConnection);
482        }
483    }
484
485    void addIceCandidate(IceCandidate iceCandidate) {
486        requirePeerConnection().addIceCandidate(iceCandidate);
487    }
488
489    private CameraEnumerator getCameraEnumerator() {
490        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
491            return new Camera2Enumerator(requireContext());
492        } else {
493            return new Camera1Enumerator();
494        }
495    }
496
497    private Optional<CapturerChoice> getVideoCapturer() {
498        final CameraEnumerator enumerator = getCameraEnumerator();
499        final Set<String> deviceNames = ImmutableSet.copyOf(enumerator.getDeviceNames());
500        for (final String deviceName : deviceNames) {
501            if (enumerator.isFrontFacing(deviceName)) {
502                final CapturerChoice capturerChoice = of(enumerator, deviceName, deviceNames);
503                if (capturerChoice == null) {
504                    return Optional.absent();
505                }
506                capturerChoice.isFrontCamera = true;
507                return Optional.of(capturerChoice);
508            }
509        }
510        if (deviceNames.size() == 0) {
511            return Optional.absent();
512        } else {
513            return Optional.fromNullable(of(enumerator, Iterables.get(deviceNames, 0), deviceNames));
514        }
515    }
516
517    public PeerConnection.PeerConnectionState getState() {
518        return requirePeerConnection().connectionState();
519    }
520
521    EglBase.Context getEglBaseContext() {
522        return this.eglBase.getEglBaseContext();
523    }
524
525    Optional<VideoTrack> getLocalVideoTrack() {
526        return Optional.fromNullable(this.localVideoTrack);
527    }
528
529    Optional<VideoTrack> getRemoteVideoTrack() {
530        return Optional.fromNullable(this.remoteVideoTrack);
531    }
532
533    private PeerConnection requirePeerConnection() {
534        final PeerConnection peerConnection = this.peerConnection;
535        if (peerConnection == null) {
536            throw new IllegalStateException("initialize PeerConnection first");
537        }
538        return peerConnection;
539    }
540
541    private Context requireContext() {
542        final Context context = this.context;
543        if (context == null) {
544            throw new IllegalStateException("call setup first");
545        }
546        return context;
547    }
548
549    AppRTCAudioManager getAudioManager() {
550        return appRTCAudioManager;
551    }
552
553    public interface EventCallback {
554        void onIceCandidate(IceCandidate iceCandidate);
555
556        void onConnectionChange(PeerConnection.PeerConnectionState newState);
557
558        void onAudioDeviceChanged(AppRTCAudioManager.AudioDevice selectedAudioDevice, Set<AppRTCAudioManager.AudioDevice> availableAudioDevices);
559    }
560
561    private static abstract class SetSdpObserver implements SdpObserver {
562
563        @Override
564        public void onCreateSuccess(org.webrtc.SessionDescription sessionDescription) {
565            throw new IllegalStateException("Not able to use SetSdpObserver");
566        }
567
568        @Override
569        public void onCreateFailure(String s) {
570            throw new IllegalStateException("Not able to use SetSdpObserver");
571        }
572
573    }
574
575    private static abstract class CreateSdpObserver implements SdpObserver {
576
577
578        @Override
579        public void onSetSuccess() {
580            throw new IllegalStateException("Not able to use CreateSdpObserver");
581        }
582
583
584        @Override
585        public void onSetFailure(String s) {
586            throw new IllegalStateException("Not able to use CreateSdpObserver");
587        }
588    }
589
590    static class InitializationException extends Exception {
591
592        private InitializationException(final Throwable throwable) {
593            super(throwable);
594        }
595
596        private InitializationException(final String message) {
597            super(message);
598        }
599    }
600
601    private static class CapturerChoice {
602        private final CameraVideoCapturer cameraVideoCapturer;
603        private final CameraEnumerationAndroid.CaptureFormat captureFormat;
604        private final Set<String> availableCameras;
605        private boolean isFrontCamera = false;
606
607        CapturerChoice(CameraVideoCapturer cameraVideoCapturer, CameraEnumerationAndroid.CaptureFormat captureFormat, Set<String> cameras) {
608            this.cameraVideoCapturer = cameraVideoCapturer;
609            this.captureFormat = captureFormat;
610            this.availableCameras = cameras;
611        }
612
613        int getFrameRate() {
614            return Math.max(captureFormat.framerate.min, Math.min(CAPTURING_MAX_FRAME_RATE, captureFormat.framerate.max));
615        }
616    }
617}