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("Unable to initialize PeerConnectionFactory", e);
218        }
219        try {
220            this.eglBase = EglBase.create();
221        } catch (final RuntimeException e) {
222            throw new InitializationException("Unable to create EGL base", e);
223        }
224        this.context = service;
225        this.toneManager = service.getJingleConnectionManager().toneManager;
226        mainHandler.post(() -> {
227            appRTCAudioManager = AppRTCAudioManager.create(service, speakerPhonePreference);
228            toneManager.setAppRtcAudioManagerHasControl(true);
229            appRTCAudioManager.start(audioManagerEvents);
230            eventCallback.onAudioDeviceChanged(appRTCAudioManager.getSelectedAudioDevice(), appRTCAudioManager.getAudioDevices());
231        });
232    }
233
234    synchronized void initializePeerConnection(final Set<Media> media, final List<PeerConnection.IceServer> iceServers) throws InitializationException {
235        Preconditions.checkState(this.eglBase != null);
236        Preconditions.checkNotNull(media);
237        Preconditions.checkArgument(media.size() > 0, "media can not be empty when initializing peer connection");
238        final boolean setUseHardwareAcousticEchoCanceler = WebRtcAudioEffects.canUseAcousticEchoCanceler() && !HARDWARE_AEC_BLACKLIST.contains(Build.MODEL);
239        Log.d(Config.LOGTAG, String.format("setUseHardwareAcousticEchoCanceler(%s) model=%s", setUseHardwareAcousticEchoCanceler, Build.MODEL));
240        PeerConnectionFactory peerConnectionFactory = PeerConnectionFactory.builder()
241                .setVideoDecoderFactory(new DefaultVideoDecoderFactory(eglBase.getEglBaseContext()))
242                .setVideoEncoderFactory(new DefaultVideoEncoderFactory(eglBase.getEglBaseContext(), true, true))
243                .setAudioDeviceModule(JavaAudioDeviceModule.builder(context)
244                        .setUseHardwareAcousticEchoCanceler(setUseHardwareAcousticEchoCanceler)
245                        .createAudioDeviceModule()
246                )
247                .createPeerConnectionFactory();
248
249
250        final MediaStream stream = peerConnectionFactory.createLocalMediaStream("my-media-stream");
251
252        final Optional<CapturerChoice> optionalCapturerChoice = media.contains(Media.VIDEO) ? getVideoCapturer() : Optional.absent();
253
254        if (optionalCapturerChoice.isPresent()) {
255            this.capturerChoice = optionalCapturerChoice.get();
256            final CameraVideoCapturer capturer = this.capturerChoice.cameraVideoCapturer;
257            final VideoSource videoSource = peerConnectionFactory.createVideoSource(false);
258            SurfaceTextureHelper surfaceTextureHelper = SurfaceTextureHelper.create("webrtc", eglBase.getEglBaseContext());
259            capturer.initialize(surfaceTextureHelper, requireContext(), videoSource.getCapturerObserver());
260            Log.d(Config.LOGTAG, String.format("start capturing at %dx%d@%d", capturerChoice.captureFormat.width, capturerChoice.captureFormat.height, capturerChoice.getFrameRate()));
261            capturer.startCapture(capturerChoice.captureFormat.width, capturerChoice.captureFormat.height, capturerChoice.getFrameRate());
262
263            this.localVideoTrack = peerConnectionFactory.createVideoTrack("my-video-track", videoSource);
264
265            stream.addTrack(this.localVideoTrack);
266        }
267
268
269        if (media.contains(Media.AUDIO)) {
270            //set up audio track
271            final AudioSource audioSource = peerConnectionFactory.createAudioSource(new MediaConstraints());
272            this.localAudioTrack = peerConnectionFactory.createAudioTrack("my-audio-track", audioSource);
273            stream.addTrack(this.localAudioTrack);
274        }
275
276
277        final PeerConnection.RTCConfiguration rtcConfig = new PeerConnection.RTCConfiguration(iceServers);
278        rtcConfig.tcpCandidatePolicy = PeerConnection.TcpCandidatePolicy.DISABLED; //XEP-0176 doesn't support tcp
279        rtcConfig.continualGatheringPolicy = PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY;
280        final PeerConnection peerConnection = peerConnectionFactory.createPeerConnection(rtcConfig, peerConnectionObserver);
281        if (peerConnection == null) {
282            throw new InitializationException("Unable to create PeerConnection");
283        }
284        peerConnection.addStream(stream);
285        peerConnection.setAudioPlayout(true);
286        peerConnection.setAudioRecording(true);
287        this.peerConnection = peerConnection;
288    }
289
290    synchronized void close() {
291        final PeerConnection peerConnection = this.peerConnection;
292        final CapturerChoice capturerChoice = this.capturerChoice;
293        final AppRTCAudioManager audioManager = this.appRTCAudioManager;
294        final EglBase eglBase = this.eglBase;
295        if (peerConnection != null) {
296            dispose(peerConnection);
297            this.peerConnection = null;
298        }
299        if (audioManager != null) {
300            toneManager.setAppRtcAudioManagerHasControl(false);
301            mainHandler.post(audioManager::stop);
302        }
303        this.localVideoTrack = null;
304        this.remoteVideoTrack = null;
305        if (capturerChoice != null) {
306            try {
307                capturerChoice.cameraVideoCapturer.stopCapture();
308            } catch (InterruptedException e) {
309                Log.e(Config.LOGTAG, "unable to stop capturing");
310            }
311        }
312        if (eglBase != null) {
313            eglBase.release();
314            this.eglBase = null;
315        }
316    }
317
318    synchronized void verifyClosed() {
319        if (this.peerConnection != null
320                || this.eglBase != null
321                || this.localVideoTrack != null
322                || this.remoteVideoTrack != null) {
323            final IllegalStateException e = new IllegalStateException("WebRTCWrapper hasn't been closed properly");
324            Log.e(Config.LOGTAG, "verifyClosed() failed. Going to throw", e);
325            throw e;
326        }
327    }
328
329    boolean isCameraSwitchable() {
330        final CapturerChoice capturerChoice = this.capturerChoice;
331        return capturerChoice != null && capturerChoice.availableCameras.size() > 1;
332    }
333
334    boolean isFrontCamera() {
335        final CapturerChoice capturerChoice = this.capturerChoice;
336        return capturerChoice == null || capturerChoice.isFrontCamera;
337    }
338
339    ListenableFuture<Boolean> switchCamera() {
340        final CapturerChoice capturerChoice = this.capturerChoice;
341        if (capturerChoice == null) {
342            return Futures.immediateFailedFuture(new IllegalStateException("CameraCapturer has not been initialized"));
343        }
344        final SettableFuture<Boolean> future = SettableFuture.create();
345        capturerChoice.cameraVideoCapturer.switchCamera(new CameraVideoCapturer.CameraSwitchHandler() {
346            @Override
347            public void onCameraSwitchDone(boolean isFrontCamera) {
348                capturerChoice.isFrontCamera = isFrontCamera;
349                future.set(isFrontCamera);
350            }
351
352            @Override
353            public void onCameraSwitchError(final String message) {
354                future.setException(new IllegalStateException(String.format("Unable to switch camera %s", message)));
355            }
356        });
357        return future;
358    }
359
360    boolean isMicrophoneEnabled() {
361        final AudioTrack audioTrack = this.localAudioTrack;
362        if (audioTrack == null) {
363            throw new IllegalStateException("Local audio track does not exist (yet)");
364        }
365        try {
366            return audioTrack.enabled();
367        } catch (final IllegalStateException e) {
368            //sometimes UI might still be rendering the buttons when a background thread has already ended the call
369            return false;
370        }
371    }
372
373    void setMicrophoneEnabled(final boolean enabled) {
374        final AudioTrack audioTrack = this.localAudioTrack;
375        if (audioTrack == null) {
376            throw new IllegalStateException("Local audio track does not exist (yet)");
377        }
378        audioTrack.setEnabled(enabled);
379    }
380
381    boolean isVideoEnabled() {
382        final VideoTrack videoTrack = this.localVideoTrack;
383        if (videoTrack == null) {
384            throw new IllegalStateException("Local video track does not exist");
385        }
386        return videoTrack.enabled();
387    }
388
389    void setVideoEnabled(final boolean enabled) {
390        final VideoTrack videoTrack = this.localVideoTrack;
391        if (videoTrack == null) {
392            throw new IllegalStateException("Local video track does not exist");
393        }
394        videoTrack.setEnabled(enabled);
395    }
396
397    ListenableFuture<SessionDescription> createOffer() {
398        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
399            final SettableFuture<SessionDescription> future = SettableFuture.create();
400            peerConnection.createOffer(new CreateSdpObserver() {
401                @Override
402                public void onCreateSuccess(SessionDescription sessionDescription) {
403                    future.set(sessionDescription);
404                }
405
406                @Override
407                public void onCreateFailure(String s) {
408                    future.setException(new IllegalStateException("Unable to create offer: " + s));
409                }
410            }, new MediaConstraints());
411            return future;
412        }, MoreExecutors.directExecutor());
413    }
414
415    ListenableFuture<SessionDescription> createAnswer() {
416        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
417            final SettableFuture<SessionDescription> future = SettableFuture.create();
418            peerConnection.createAnswer(new CreateSdpObserver() {
419                @Override
420                public void onCreateSuccess(SessionDescription sessionDescription) {
421                    future.set(sessionDescription);
422                }
423
424                @Override
425                public void onCreateFailure(String s) {
426                    future.setException(new IllegalStateException("Unable to create answer: " + s));
427                }
428            }, new MediaConstraints());
429            return future;
430        }, MoreExecutors.directExecutor());
431    }
432
433    ListenableFuture<Void> setLocalDescription(final SessionDescription sessionDescription) {
434        Log.d(EXTENDED_LOGGING_TAG, "setting local description:");
435        for (final String line : sessionDescription.description.split(eu.siacs.conversations.xmpp.jingle.SessionDescription.LINE_DIVIDER)) {
436            Log.d(EXTENDED_LOGGING_TAG, line);
437        }
438        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
439            final SettableFuture<Void> future = SettableFuture.create();
440            peerConnection.setLocalDescription(new SetSdpObserver() {
441                @Override
442                public void onSetSuccess() {
443                    future.set(null);
444                }
445
446                @Override
447                public void onSetFailure(final String s) {
448                    future.setException(new IllegalArgumentException("unable to set local session description: " + s));
449
450                }
451            }, sessionDescription);
452            return future;
453        }, MoreExecutors.directExecutor());
454    }
455
456    ListenableFuture<Void> setRemoteDescription(final SessionDescription sessionDescription) {
457        Log.d(EXTENDED_LOGGING_TAG, "setting remote description:");
458        for (final String line : sessionDescription.description.split(eu.siacs.conversations.xmpp.jingle.SessionDescription.LINE_DIVIDER)) {
459            Log.d(EXTENDED_LOGGING_TAG, line);
460        }
461        return Futures.transformAsync(getPeerConnectionFuture(), peerConnection -> {
462            final SettableFuture<Void> future = SettableFuture.create();
463            peerConnection.setRemoteDescription(new SetSdpObserver() {
464                @Override
465                public void onSetSuccess() {
466                    future.set(null);
467                }
468
469                @Override
470                public void onSetFailure(String s) {
471                    future.setException(new IllegalArgumentException("unable to set remote session description: " + s));
472
473                }
474            }, sessionDescription);
475            return future;
476        }, MoreExecutors.directExecutor());
477    }
478
479    @Nonnull
480    private ListenableFuture<PeerConnection> getPeerConnectionFuture() {
481        final PeerConnection peerConnection = this.peerConnection;
482        if (peerConnection == null) {
483            return Futures.immediateFailedFuture(new IllegalStateException("initialize PeerConnection first"));
484        } else {
485            return Futures.immediateFuture(peerConnection);
486        }
487    }
488
489    void addIceCandidate(IceCandidate iceCandidate) {
490        requirePeerConnection().addIceCandidate(iceCandidate);
491    }
492
493    private CameraEnumerator getCameraEnumerator() {
494        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
495            return new Camera2Enumerator(requireContext());
496        } else {
497            return new Camera1Enumerator();
498        }
499    }
500
501    private Optional<CapturerChoice> getVideoCapturer() {
502        final CameraEnumerator enumerator = getCameraEnumerator();
503        final Set<String> deviceNames = ImmutableSet.copyOf(enumerator.getDeviceNames());
504        for (final String deviceName : deviceNames) {
505            if (enumerator.isFrontFacing(deviceName)) {
506                final CapturerChoice capturerChoice = of(enumerator, deviceName, deviceNames);
507                if (capturerChoice == null) {
508                    return Optional.absent();
509                }
510                capturerChoice.isFrontCamera = true;
511                return Optional.of(capturerChoice);
512            }
513        }
514        if (deviceNames.size() == 0) {
515            return Optional.absent();
516        } else {
517            return Optional.fromNullable(of(enumerator, Iterables.get(deviceNames, 0), deviceNames));
518        }
519    }
520
521    public PeerConnection.PeerConnectionState getState() {
522        return requirePeerConnection().connectionState();
523    }
524
525    EglBase.Context getEglBaseContext() {
526        return this.eglBase.getEglBaseContext();
527    }
528
529    Optional<VideoTrack> getLocalVideoTrack() {
530        return Optional.fromNullable(this.localVideoTrack);
531    }
532
533    Optional<VideoTrack> getRemoteVideoTrack() {
534        return Optional.fromNullable(this.remoteVideoTrack);
535    }
536
537    private PeerConnection requirePeerConnection() {
538        final PeerConnection peerConnection = this.peerConnection;
539        if (peerConnection == null) {
540            throw new IllegalStateException("initialize PeerConnection first");
541        }
542        return peerConnection;
543    }
544
545    private Context requireContext() {
546        final Context context = this.context;
547        if (context == null) {
548            throw new IllegalStateException("call setup first");
549        }
550        return context;
551    }
552
553    AppRTCAudioManager getAudioManager() {
554        return appRTCAudioManager;
555    }
556
557    public interface EventCallback {
558        void onIceCandidate(IceCandidate iceCandidate);
559
560        void onConnectionChange(PeerConnection.PeerConnectionState newState);
561
562        void onAudioDeviceChanged(AppRTCAudioManager.AudioDevice selectedAudioDevice, Set<AppRTCAudioManager.AudioDevice> availableAudioDevices);
563    }
564
565    private static abstract class SetSdpObserver implements SdpObserver {
566
567        @Override
568        public void onCreateSuccess(org.webrtc.SessionDescription sessionDescription) {
569            throw new IllegalStateException("Not able to use SetSdpObserver");
570        }
571
572        @Override
573        public void onCreateFailure(String s) {
574            throw new IllegalStateException("Not able to use SetSdpObserver");
575        }
576
577    }
578
579    private static abstract class CreateSdpObserver implements SdpObserver {
580
581
582        @Override
583        public void onSetSuccess() {
584            throw new IllegalStateException("Not able to use CreateSdpObserver");
585        }
586
587
588        @Override
589        public void onSetFailure(String s) {
590            throw new IllegalStateException("Not able to use CreateSdpObserver");
591        }
592    }
593
594    static class InitializationException extends Exception {
595
596        private InitializationException(final String message, final Throwable throwable) {
597            super(message, throwable);
598        }
599
600        private InitializationException(final String message) {
601            super(message);
602        }
603    }
604
605    private static class CapturerChoice {
606        private final CameraVideoCapturer cameraVideoCapturer;
607        private final CameraEnumerationAndroid.CaptureFormat captureFormat;
608        private final Set<String> availableCameras;
609        private boolean isFrontCamera = false;
610
611        CapturerChoice(CameraVideoCapturer cameraVideoCapturer, CameraEnumerationAndroid.CaptureFormat captureFormat, Set<String> cameras) {
612            this.cameraVideoCapturer = cameraVideoCapturer;
613            this.captureFormat = captureFormat;
614            this.availableCameras = cameras;
615        }
616
617        int getFrameRate() {
618            return Math.max(captureFormat.framerate.min, Math.min(CAPTURING_MAX_FRAME_RATE, captureFormat.framerate.max));
619        }
620    }
621}