iOS MultiPlayer Swift¶

Overview¶

The example shows how to publish a WebRTC stream to a server and play multiple streams from the server (one-to-mant videochat). It may be also used as memory consumption test while decoding multiple high resolution streams.

On the screenshot below the 1280x720 stream is publishing and playing. The published stream from the device camera is displayed above, and four playing streams are displayed below

Analyzing the code¶

To analyze the code let's take MultiPlayerSwift example, which can be downloaded from GitHub.

The class for main view of the application: MultiPlayerController (implementation file MultiPlayerController.swift).

1. Import of API¶

code

import FPWCSApi2Swift

2. Session creation and connection to server¶

WCSSession, WCSSession.connect code

The session options include:

URL of WCS server
appKey of server-side REST hook application (defaultApp)

@IBAction func startPressed(_ sender: Any) {
    ...

    if (startButton.title(for: .normal) == "PUBLISH AND PLAY") {
        if (session == nil) {
            let options = FPWCSApi2SessionOptions()
            options.urlServer = urlField.text
            options.appKey = "defaultApp"
            do {
                try session = WCSSession(options)
            } catch {
                print(error)
            }
        }
        ...
        session?.connect()
    } else {
        ...
    }

}

3. Stream publishing¶

WCSSession.createStream, WCSStream.publish code

The following stream options are passed to createStream method:

stream name
view to display video
width and height publishing constraint

func publish() {
    let options = FPWCSApi2StreamOptions()
    options.name = streamName.text
    options.display = localDisplay.videoView

    let ret = FPWCSApi2MediaConstraints()

    let video = FPWCSApi2VideoConstraints()
    video.minWidth = Int(widthField.text ?? "0") ?? 0
    video.maxWidth = video.minWidth
    video.minHeight = Int(heightField.text ?? "0") ?? 0
    video.maxHeight = video.minHeight
    ret.video = video

    options.constraints = ret
    do {
        publishStream = try session!.createStream(options)
    } catch {
        print(error);
    }

    ...
    do {
        try publishStream?.publish()
    } catch {
        print(error);
    }
}

4. Start four stream instances playback after successful publishing¶

code

fileprivate func onPublishing(_ stream:FPWCSApi2Stream) {
    playStreamLT = self.play(display: remoteDisplayLT);
    playStreamRT = self.play(display: remoteDisplayRT);
    playStreamLB = self.play(display: remoteDisplayLB);
    playStreamRB = self.play(display: remoteDisplayRB);

    startButton.setTitle("STOP", for:.normal)
    changeViewState(startButton, true);
    changeViewState(switchCameraButton, true);
}

5. Stream playback¶

WCSSession.createStream, WCSStream.play code

The following stream options are passed to createStream method:

stream name
view to display video

func play(display: WebRTCView) -> WCSStream? {
    let options = FPWCSApi2StreamOptions()
    options.name = streamName.text;
    options.display = display.videoView;
    do {
        let playStream = try session!.createStream(options)

        ...
        try playStream.play()
        return playStream;
    } catch {
        print(error);
    }
    return nil;
}

6. Camera switching¶

WCSStream.switchCamera code

@IBAction func switchCameraPressed(_ sender: Any) {
    publishStream?.switchCamera()
}

7. Playback stop when publishing is stopped¶

WCSStream.stop code

fileprivate func onUnpublished() {
    do {
        try playStreamLT?.stop();
    } catch {
        print(error);
    }
    do {
        try playStreamRT?.stop();
    } catch {
        print(error);
    }
    do {
        try playStreamLB?.stop();
    } catch {
        print(error);
    }
    do {
        try playStreamRB?.stop();
    } catch {
        print(error);
    }
}

8. Closing the connection¶

WCSSession.disconnect code

@IBAction func startPressed(_ sender: Any) {
    changeViewState(startButton, false)
    changeViewState(urlField, false)
    changeViewState(streamName, false)

    if (startButton.title(for: .normal) == "PUBLISH AND PLAY") {
        ...
        session?.connect()
    } else {
        session?.disconnect()
    }

}