WebRTC iOS 本地视频轨道 bytesSent 为 0

Question

我在 Cocoapods 中使用 GoogleWebRTC 版本 1.1.22075 创建了我的 iOS WebRTC 应用程序。另一个客户端是 Web 应用程序。我们已经建立了两个 WebRTC 客户端之间的连接。音频很好。两个 WebRTC 客户端都可以接收和发送音频，但是当涉及到视频时，iOS 本地视频轨道根本没有发送任何字节。在 iOS 应用的 RTCLegacyStatsReport 中，视频的 bytesSent 为 0。

以下是视频的统计数据：

reportId: ssrc_2385920718_send type: ssrc googAdaptationChanges: 0 ssrc: 2385920718 googFrameWidthSent: 0 googBandwidthLimitedResolution: false bytesSent: 0 googCodecName: VP8 codecImplementationName: unknown googFirsReceived: 0 packetsLost: 0 googHasEnteredLowResolution: false googCpuLimitedResolution: false googTrackId: ios_local_video_stream framesEncoded: 0 googPlisReceived: 0 mediaType: video packetsSent: 0 googFrameRateSent: 0 googContentType: realtime googFrameHeightSent: 0 googNacksReceived: 0 googFrameRateInput: 0 transportId: Channel-audio-1 googAvgEncodeMs: 0 googRtt: 0 googEncodeUsagePercent: 0

这是我如何获取捕获设备、创建本地视频轨道以及渲染视频以在本地查看的代码。

func onLocalStreamReadyForRender() {
    print("onLocalStreamReadyForRender")
    let frame = localVideoView!.frame

    let rtcVideoView = RTCCameraPreviewView.init(frame: CGRect.init())
    rtcVideoView.frame = frame
    rtcVideoView.frame.origin.x = 0
    rtcVideoView.frame.origin.y = 0
    self.localVideoView?.addSubview(rtcVideoView)

    currVideoCaptureSession!.startRunning()

    if let _ = currVideoCaptureSession {
        rtcVideoView.captureSession = currVideoCaptureSession!
    }
}

fileprivate func onVideoTrackCreated(_ videoTrack: RTCVideoTrack?, _ videoSource: RTCVideoSource?, _ videoCaptureSession: AVCaptureSession?) {
    print("onVideoTrackCreated")

    currVideoTrack = videoTrack
    currVideoSource = videoSource
    currVideoCaptureSession = videoCaptureSession

    if let _ = currVideoTrack {
        localStream!.addVideoTrack(videoTrack!)
        print("localstream added video track with track id \(String(describing: currVideoTrack?.trackId))")

        onLocalStreamReadyForRender()
    }

    for stream in peerConn!.localStreams {
        if stream.streamId == Config.mediaTrackLabel {
            peerConn!.remove(localStream!)
        }
    }

    peerConn!.add(localStream!)
}

func createLocalVideoTrack(position: AVCaptureDevice.Position) {
    if let captureDevice = getCaptureDevice(position: position) {
        print("createLocalVideoTrack")

        let videoSource = peerConnFactory.videoSource()
        let rtcCamVidCapturer = RTCCameraVideoCapturer(delegate: videoSource)

        rtcCamVidCapturer.startCapture(
            with: captureDevice.device,
            format: captureDevice.format,
            fps: captureDevice.fps,
            completionHandler:
            {
                (error: Error?) in
                if let captureError = error {
                    print("Error RTCCameraVideoCapturer startCapture \(captureError)")
                }
                else {
                    print("RTCCameraVideoCapturer startCapture success")
                    let videoTrack = self.peerConnFactory.videoTrack(with: videoSource, trackId: Config.mediaTrackVideoLabel)
                    self.mediaTrackDelegate?.onVideoTrackCreated(videoTrack, videoSource, rtcCamVidCapturer.captureSession)
                }
            })
    }
}

func getCaptureDevice(position: AVCaptureDevice.Position) -> (device: AVCaptureDevice, format: AVCaptureDevice.Format, fps: Int)? {
    for avCaptureDevice in RTCCameraVideoCapturer.captureDevices() {
        if avCaptureDevice.position == position {
            let supportedActiveFormat = avCaptureDevice.activeFormat
            let maxFrameRate = supportedActiveFormat.videoSupportedFrameRateRanges[0].maxFrameRate
            let minFrameRate = supportedActiveFormat.videoSupportedFrameRateRanges[0].minFrameRate
            //let midFrameRate = minFrameRate + ((maxFrameRate - minFrameRate)/2)
            let fps = maxFrameRate

            print("getCaptureDevice uniqueId:\(avCaptureDevice.uniqueID), supportedActiveFormat:\(supportedActiveFormat), fps:\(fps), deviceType:\(avCaptureDevice.deviceType), isConnected:\(avCaptureDevice.isConnected), localizedName:\(avCaptureDevice.localizedName)")

            return (device: avCaptureDevice, format: supportedActiveFormat, fps: Int(fps))
        }
    }

    print("Error no capture device returned")
    return nil
}

顺便说一下，我在 iPad mini 2nd gen OS version 11.2.6 上测试它

任何帮助将不胜感激。谢谢！

Answer 1

我设法解决了这个问题。这是因为 RTCCameraVideoCapturer 一被创建就被销毁了。