Use new RTCCameraVideoCapturer in AppRTCMobile.

webrtc/examples/objc/AppRTCMobile/ARDAppClient.m

Index: webrtc/examples/objc/AppRTCMobile/ARDAppClient.m
diff --git a/webrtc/examples/objc/AppRTCMobile/ARDAppClient.m b/webrtc/examples/objc/AppRTCMobile/ARDAppClient.m
index ef38138319ac56b2e9655eaec5cedef932cbd2f7..623fad4f285ed35d312b103c456248fc8783c958 100644
--- a/webrtc/examples/objc/AppRTCMobile/ARDAppClient.m
+++ b/webrtc/examples/objc/AppRTCMobile/ARDAppClient.m
@@ -12,6 +12,7 @@
 
 #import "WebRTC/RTCAVFoundationVideoSource.h"
 #import "WebRTC/RTCAudioTrack.h"
+#import "WebRTC/RTCCameraVideoCapturer.h"
 #import "WebRTC/RTCConfiguration.h"
 #import "WebRTC/RTCFileLogger.h"
 #import "WebRTC/RTCIceServer.h"
@@ -21,6 +22,7 @@
 #import "WebRTC/RTCPeerConnectionFactory.h"
 #import "WebRTC/RTCRtpSender.h"
 #import "WebRTC/RTCTracing.h"
+#import "WebRTC/RTCVideoTrack.h"
 
 #import "ARDAppEngineClient.h"
 #import "ARDJoinResponse.h"
@@ -100,6 +102,9 @@ static int const kKbpsMultiplier = 1000;
   RTCFileLogger *_fileLogger;
   ARDTimerProxy *_statsTimer;
   ARDSettingsModel *_settings;
+  RTCCameraVideoCapturer *_capturer;
+  RTCVideoTrack *_localVideoTrack;
+  BOOL _usingFrontCamera;
 }
 
 @synthesize shouldGetStats = _shouldGetStats;
@@ -300,11 +305,16 @@ static int const kKbpsMultiplier = 1000;
     // Disconnect from collider.
     _channel = nil;
   }
+  if (_capturer) {
+    [_capturer stopCapture];
+    _capturer = nil;
+  }
   _clientId = nil;
   _roomId = nil;
   _isInitiator = NO;
   _hasReceivedSdp = NO;
   _messageQueue = [NSMutableArray array];
+  _localVideoTrack = nil;
 #if defined(WEBRTC_IOS)
   [_factory stopAecDump];
   [_peerConnection stopRtcEventLog];
@@ -318,6 +328,11 @@ static int const kKbpsMultiplier = 1000;
 #endif
 }
 
+- (void)switchCamera {
+  _usingFrontCamera = !_usingFrontCamera;
+  [self startCapture];
+}
+
 #pragma mark - ARDSignalingChannelDelegate
 
 - (void)channel:(id<ARDSignalingChannel>)channel
@@ -666,11 +681,12 @@ static int const kKbpsMultiplier = 1000;
   RTCRtpSender *sender =
       [_peerConnection senderWithKind:kRTCMediaStreamTrackKindVideo
                              streamId:kARDMediaStreamId];
-  RTCVideoTrack *track = [self createLocalVideoTrack];
-  if (track) {
-    sender.track = track;
-    [_delegate appClient:self didReceiveLocalVideoTrack:track];
+  _localVideoTrack = [self createLocalVideoTrack];
+  if (_localVideoTrack) {
+    sender.track = _localVideoTrack;
+    [_delegate appClient:self didReceiveLocalVideoTrack:_localVideoTrack];
   }
+  [_delegate appClient:self didReceiveLocalVideoTrack:_localVideoTrack];

[daniela-webrtc, 2017/04/03 10:16:50]

Not sure if we should invoke the delegate with nil here to indicate the
localTrack was not created. If there is such need it's better to have additional
callback like `appClientFailedToCreateLocalVideoTrack` or adjust the existing
method to included error parameter.

[sakal, 2017/04/04 09:18:23]

Oops, this was added by accident.

 
   return sender;
 }
@@ -709,6 +725,55 @@ static int const kKbpsMultiplier = 1000;
   return sender;
 }
 
+- (void)startCapture {

[daniela-webrtc, 2017/04/03 10:16:50]

This should be exposed in the interface. Also, it signature can be changed to:
`startCaptureWithDevice:` That way you can ditch the _usingFrontCamera ivar and
move the responsibility of capturing device elsewhere (as it should be since
AppDelegate becomes quite cluttered otherwise).

[sakal, 2017/04/04 09:18:23]

Moved to CaptureController as discussed.

+  AVCaptureDevicePosition position =
+      _usingFrontCamera ? AVCaptureDevicePositionFront : AVCaptureDevicePositionBack;
+  AVCaptureDevice *device = [self findDeviceForPosition:position];
+  AVCaptureDeviceFormat *format = [self selectFormatForDevice:device];
+  int fps = [self selectFpsForFormat:format];
+
+  [_capturer startCaptureWithDevice:device format:format fps:fps];
+}
+
+- (AVCaptureDevice *)findDeviceForPosition:(AVCaptureDevicePosition)position {
+  NSArray<AVCaptureDevice *> *captureDevices = [RTCCameraVideoCapturer captureDevices];
+  for (AVCaptureDevice *device in captureDevices) {
+    if (device.position == position) {
+      return device;
+    }
+  }
+  return captureDevices[0];
+}
+
+- (AVCaptureDeviceFormat *)selectFormatForDevice:(AVCaptureDevice *)device {
+  NSArray<AVCaptureDeviceFormat *> *formats =
+      [RTCCameraVideoCapturer supportedFormatsForDevice:device];
+  int targetWidth = [_settings currentVideoResolutionWidthFromStore];
+  int targetHeight = [_settings currentVideoResolutionHeightFromStore];
+  AVCaptureDeviceFormat *selectedFormat;

[daniela-webrtc, 2017/04/03 10:16:50]

Preferably explicitly set pointers to nil.

[sakal, 2017/04/04 09:18:23]

Done.

+  int currentDiff = INT_MAX;
+
+  for (AVCaptureDeviceFormat *format in formats) {
+    CMVideoDimensions dimension = CMVideoFormatDescriptionGetDimensions(format.formatDescription);
+    int diff = abs(targetWidth - dimension.width) + abs(targetHeight - dimension.height);
+    if (diff < currentDiff) {
+      selectedFormat = format;
+      currentDiff = diff;
+    }
+  }
+
+  NSAssert(selectedFormat != nil, @"No suitable capture format found.");
+  return selectedFormat;
+}
+
+- (int)selectFpsForFormat:(AVCaptureDeviceFormat *)format {
+  Float64 maxFramerate = 0;
+  for (AVFrameRateRange *fpsRange in format.videoSupportedFrameRateRanges) {
+    maxFramerate = fmax(maxFramerate, fpsRange.maxFrameRate);
+  }
+  return maxFramerate;
+}
+
 - (RTCVideoTrack *)createLocalVideoTrack {
   RTCVideoTrack* localVideoTrack = nil;
   // The iOS simulator doesn't provide any sort of camera capture
@@ -716,10 +781,11 @@ static int const kKbpsMultiplier = 1000;
   // trying to open a local stream.
 #if !TARGET_IPHONE_SIMULATOR
   if (!_isAudioOnly) {
-    RTCMediaConstraints *cameraConstraints =
-        [self cameraConstraints];
-    RTCAVFoundationVideoSource *source =
-        [_factory avFoundationVideoSourceWithConstraints:cameraConstraints];
+    RTCVideoSource *source = [_factory videoSource];
+    _capturer = [[RTCCameraVideoCapturer alloc] initWithDelegate:source];
+    [_delegate appClient:self didCreateLocalCapturer:_capturer];
+    _usingFrontCamera = true;
+    [self startCapture];

[daniela-webrtc, 2017/04/03 10:16:50]

[startCapture] should not be here but rather exposed in the interface of this
class so that it can be invoked when convenient (for instance in this case in
the delegate callback `appClient:didReceiveLocalVideoTrack:`.
Also, this way `createLocalVideoTrack`has a lot of side effects and does way
more than it's naming suggests.

[sakal, 2017/04/04 09:18:23]

Done.

     localVideoTrack =
         [_factory videoTrackWithSource:source
                                trackId:kARDVideoTrackId];
@@ -764,13 +830,6 @@ static int const kKbpsMultiplier = 1000;
    return constraints;
 }
 
-- (RTCMediaConstraints *)cameraConstraints {
-  RTCMediaConstraints *cameraConstraints = [[RTCMediaConstraints alloc]
-      initWithMandatoryConstraints:nil
-               optionalConstraints:[_settings currentMediaConstraintFromStoreAsRTCDictionary]];
-  return cameraConstraints;
-}
-
 - (RTCMediaConstraints *)defaultAnswerConstraints {
   return [self defaultOfferConstraints];
 }