iOS SWIFT - WebRTC change from Front Camera to back Camera - ios

Question

WebRTC video by default uses Front Camera, which works fine. However, i need to switch it to back camera, and i have not been able to find any code to do that.
Which part do i need to edit?
Is it the localView or localVideoTrack or capturer?

Answer 1

Swift 3.0
Peer connection can have only one 'RTCVideoTrack' for sending video stream.
At first, for change camera front/back you must remove current video track on peer connection.
After then, you create new 'RTCVideoTrack' on camera which you need, and set this for peer connection.
I used this methods.
func swapCameraToFront() {
let localStream: RTCMediaStream? = peerConnection?.localStreams.first as? RTCMediaStream
localStream?.removeVideoTrack(localStream?.videoTracks.first as! RTCVideoTrack)
let localVideoTrack: RTCVideoTrack? = createLocalVideoTrack()
if localVideoTrack != nil {
localStream?.addVideoTrack(localVideoTrack)
delegate?.appClient(self, didReceiveLocalVideoTrack: localVideoTrack!)
}
peerConnection?.remove(localStream)
peerConnection?.add(localStream)
}
func swapCameraToBack() {
let localStream: RTCMediaStream? = peerConnection?.localStreams.first as? RTCMediaStream
localStream?.removeVideoTrack(localStream?.videoTracks.first as! RTCVideoTrack)
let localVideoTrack: RTCVideoTrack? = createLocalVideoTrackBackCamera()
if localVideoTrack != nil {
localStream?.addVideoTrack(localVideoTrack)
delegate?.appClient(self, didReceiveLocalVideoTrack: localVideoTrack!)
}
peerConnection?.remove(localStream)
peerConnection?.add(localStream)
}

Answer 2

As of now I only have the answer in Objective C language in regard to Ankit's comment below. I will convert it into Swift after some time.
You can check the below code
- (RTCVideoTrack *)createLocalVideoTrack {
RTCVideoTrack *localVideoTrack = nil;
NSString *cameraID = nil;
for (AVCaptureDevice *captureDevice in [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]) {
if (captureDevice.position == AVCaptureDevicePositionFront) {
cameraID = [captureDevice localizedName]; break;
}
}
RTCVideoCapturer *capturer = [RTCVideoCapturer capturerWithDeviceName:cameraID];
RTCMediaConstraints *mediaConstraints = [self defaultMediaStreamConstraints];
RTCVideoSource *videoSource = [_factory videoSourceWithCapturer:capturer constraints:mediaConstraints];
localVideoTrack = [_factory videoTrackWithID:#"ARDAMSv0" source:videoSource];
return localVideoTrack;
}
- (RTCVideoTrack *)createLocalVideoTrackBackCamera {
RTCVideoTrack *localVideoTrack = nil;
//AVCaptureDevicePositionFront
NSString *cameraID = nil;
for (AVCaptureDevice *captureDevice in [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]) {
if (captureDevice.position == AVCaptureDevicePositionBack) {
cameraID = [captureDevice localizedName];
break;
}
}
RTCVideoCapturer *capturer = [RTCVideoCapturer capturerWithDeviceName:cameraID];
RTCMediaConstraints *mediaConstraints = [self defaultMediaStreamConstraints];
RTCVideoSource *videoSource = [_factory videoSourceWithCapturer:capturer constraints:mediaConstraints];
localVideoTrack = [_factory videoTrackWithID:#"ARDAMSv0" source:videoSource];
return localVideoTrack;
}

Answer 3

If you decide to use official Google build here the explanation:
First, you must configure your camera before call start, best place to do that in ARDVideoCallViewDelegate in method didCreateLocalCapturer
- (void)startCapture:(void (^)(BOOL succeeded))completionHandler {
AVCaptureDevicePosition position = _usingFrontCamera ? AVCaptureDevicePositionFront : AVCaptureDevicePositionBack;
__weak AVCaptureDevice *device = [self findDeviceForPosition:position];
if ([device lockForConfiguration:nil]) {
if ([device isFocusPointOfInterestSupported]) {
[device setFocusModeLockedWithLensPosition:0.9 completionHandler: nil];
}
}
AVCaptureDeviceFormat *format = [self selectFormatForDevice:device];
if (format == nil) {
RTCLogError(#"No valid formats for device %#", device);
NSAssert(NO, #"");
return;
}
NSInteger fps = [self selectFpsForFormat:format];
[_capturer startCaptureWithDevice: device
format: format
fps:fps completionHandler:^(NSError * error) {
NSLog(#"%#",error);
if (error == nil) {
completionHandler(true);
}
}];
}
Don't forget enabling capture device is asynchronous, sometime better to use completion to be sure everything done as expected.

Answer 4

I am not sure which chrome version you are using for webrtc but with v54 and above there is "bool" property called "useBackCamera" in RTCAVFoundationVideoSource class. You can make use of this property to switch between front/back camera.

Answer 5

Swift 4.0 & 'GoogleWebRTC' : '1.1.20913'
RTCAVFoundationVideoSource class has a property named useBackCamera that can be used for switching the camera used.
#interface RTCAVFoundationVideoSource : RTCVideoSource
- (instancetype)init NS_UNAVAILABLE;
/**
* Calling this function will cause frames to be scaled down to the
* requested resolution. Also, frames will be cropped to match the
* requested aspect ratio, and frames will be dropped to match the
* requested fps. The requested aspect ratio is orientation agnostic and
* will be adjusted to maintain the input orientation, so it doesn't
* matter if e.g. 1280x720 or 720x1280 is requested.
*/
- (void)adaptOutputFormatToWidth:(int)width height:(int)height fps:(int)fps;
/** Returns whether rear-facing camera is available for use. */
#property(nonatomic, readonly) BOOL canUseBackCamera;
/** Switches the camera being used (either front or back). */
#property(nonatomic, assign) BOOL useBackCamera;
/** Returns the active capture session. */
#property(nonatomic, readonly) AVCaptureSession *captureSession;
Below is the implementation for switching camera.
var useBackCamera: Bool = false
func switchCamera() {
useBackCamera = !useBackCamera
self.switchCamera(useBackCamera: useBackCamera)
}
private func switchCamera(useBackCamera: Bool) -> Void {
let localStream = peerConnection?.localStreams.first
if let videoTrack = localStream?.videoTracks.first {
localStream?.removeVideoTrack(videoTrack)
}
let localVideoTrack = createLocalVideoTrack(useBackCamera: useBackCamera)
localStream?.addVideoTrack(localVideoTrack)
self.delegate?.webRTCClientDidAddLocal(videoTrack: localVideoTrack)
if let ls = localStream {
peerConnection?.remove(ls)
peerConnection?.add(ls)
}
}
func createLocalVideoTrack(useBackCamera: Bool) -> RTCVideoTrack {
let videoSource = self.factory.avFoundationVideoSource(with: self.constraints)
videoSource.useBackCamera = useBackCamera
let videoTrack = self.factory.videoTrack(with: videoSource, trackId: "video")
return videoTrack
}

Answer 6

In the current version of WebRTC, RTCAVFoundationVideoSource has been deprecated and replaced with a
generic RTCVideoSource combined with an RTCVideoCapturer implementation.
In order to switch the camera I'm doing this:
- (void)switchCameraToPosition:(AVCaptureDevicePosition)position completionHandler:(void (^)(void))completionHandler {
if (self.cameraPosition != position) {
RTCMediaStream *localStream = self.peerConnection.localStreams.firstObject;
[localStream removeVideoTrack:self.localVideoTrack];
//[self.peerConnection removeStream:localStream];
self.localVideoTrack = [self createVideoTrack];
[self startCaptureLocalVideoWithPosition:position completionHandler:^{
[localStream addVideoTrack:self.localVideoTrack];
//[self.peerConnection addStream:localStream];
if (completionHandler) {
completionHandler();
}
}];
self.cameraPosition = position;
}
}
Take a look at the commented lines, If you start adding/removing the stream from the peer connection it will cause a delay in the video connection.
I'm using GoogleWebRTC-1.1.25102