默认情况下的webrtc视频使用前置摄像头，该摄像头正常。但是，我需要将其切换到后相机，并且我找不到任何代码来做到这一点。我需要编辑哪一部分？是LocalView，LocalVideOtrack还是Capturer？
swift 3.0
对等连接可以只有一个用于发送视频流的" rtcvideotrack"。
首先，对于更改摄像头/后部，您必须删除当前的视频跟踪对等连接。之后，您在需要的相机上创建新的" rtcvideotrack"，并将其设置为同行连接。
我使用了此方法。
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)
}
到目前为止，我只有Objective C语言的答案，即 ankit 的评论。一段时间后，我会将其转换为Swift。
您可以检查以下代码
- (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;
}
如果您决定在此处使用官方的Google构建说明：
首先，您必须在呼叫开始之前配置相机，在方法didCreateLocalCapturer
ARDVideoCallViewDelegate的最佳地点 - (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);
}
}];
}
不要忘记启用捕获设备是异步的，有时最好使用完成以确保按预期完成的所有操作。
我不确定您用于WebRTC使用的chrome版本，但是V54及更高版本在RTCAVFOUNDATIONVIDEOSOURCE类中具有" Bool"属性，称为" usebackCamera"。您可以使用此属性在前摄像头之间切换。
swift 4.0＆amp;'GoogleWebrtc'：'1.1.20913'
RTCAVFOUNDATIONVIDEOSOURCE 类具有名为 usebackCamera 的属性，可用于切换使用的相机。
@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;
以下是开关相机的实现。
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
}
在当前版本的 webrtc 中，rtcavfoundationVideoSource已被弃用并替换为通用RTCVIDEOSOURCE与RTCVIDEOCAPTURER的实现相结合。
为了切换相机，我正在执行此操作：
- (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;
}
}
看一下注释的行，如果您开始添加/删除从对等连接的流，将导致视频连接延迟。
我正在使用GoogleWebrtc-1.1.25102