controls.js¶

This module encapsulates code responsible for managing local media and room config. This includes creation of new tracks, stopping existing tracks and preparation of room config before connecting to server.

1. Wrapper function¶

createControls() code

Wrapper function which keeps controls inside the closure

const createControls = function(config) {
    ...
}

2. Create controls object¶

code

Create controls object which will hold all the html handles. Also initialize tables for displaying local tracks configuration

const controls = {
    entrance: {
        url: document.getElementById("url"),
        roomName: document.getElementById("roomName"),
        roomPin: document.getElementById("roomPin"),
        nickName: document.getElementById("nickName"),
        enter: document.getElementById("startButton")
    },
    addVideoTrack: {
        source: document.getElementById("addVideoTrackSource"),
        width: document.getElementById("addVideoTrackWidth"),
        height: document.getElementById("addVideoTrackHeight"),
        codec: document.getElementById("addVideoTrackCodec")
    },
    addAudioTrack: {
        source: document.getElementById("addAudioTrackSource"),
        channels: document.getElementById("addAudioTrackChannels")
    },
    addVideoEncoding: {
        rid: document.getElementById("addVideoTrackEncodingRid"),
        active: document.getElementById("addVideoTrackEncodingActive"),
        maxBitrate: document.getElementById("addVideoTrackEncodingMaxBitrate"),
        resolutionScale: document.getElementById("addVideoTrackEncodingResolutionScale")
    },
    tables: {
        video: $('#videoTracksTable').DataTable({
            "sDom": 't',
            "columns": [
                {
                    "className":      'details-control',
                    "orderable":      false,
                    "data":           null,
                    "defaultContent": ''
                },
                {"data": "source"},
                {"data": "width"},
                {"data": "height"},
                {"data": "codec"},
                {"data": "action"}
            ]
        }),
        audio: $('#audioTracksTable').DataTable({
            "sDom": 't',
            "columns": [
                {"data": "source"},
                {"data": "channels"},
                {"data": "action"}
            ]
        }),
        encodings: $('#videoTrackEncodingsTable').DataTable({
            "sDom": 't',
            "columns": [
                {"data": "rid"},
                {"data": "active"},
                {"data": "maxBitrate"},
                {"data": "resolutionScale"},
                {"data": "action"}
            ]
        })
    }
}

3. Fill entrance modal window fields¶

code

Populate entrance modal with provided config

//apply room config
controls.entrance.url.value = config.room.url;
controls.entrance.roomName.value = config.room.name;
controls.entrance.roomPin.value = config.room.pin;
controls.entrance.nickName.value = config.room.nickName;

4. Add new audio tracks to controls¶

addAudioTrackRow() code

Function that will add new audio tracks to controls and notify main script

const addAudioTrackRow = async function(track) {
    const stream = await getMedia([track]);
    let button = '<button id="' + stream.id + '-button" class="btn btn-primary">Delete</button>';
    const row = controls.tables.audio.row.add({
        source: track.source,
        channels: track.channels,
        action: button,
        stream: stream
    }).node();
    controls.tables.audio.draw();

    $('#' + stream.id + "-button").on('click', function(){
        //terminate stream
        console.log("terminate audio stream " + stream.id);
        let track = stream.getAudioTracks()[0];
        track.stop();
        track.dispatchEvent(new Event("ended"));
    }).prop('disabled', true);
    stream.getTracks()[0].onended = function() {
        controls.tables.audio.row(row).remove().draw();
    }
    trackCallback({
        stream: stream,
        encodings: track.encodings,
        source: track.source,
        type: track.type
    });
}

Request local media from the WebRTC API

code

const stream = await getMedia([track]);

Add track to the audio tracks table

code

let button = '<button id="' + stream.id + '-button" class="btn btn-primary">Delete</button>';
const row = controls.tables.audio.row.add({
    source: track.source,
    channels: track.channels,
    action: button,
    stream: stream
}).node();
controls.tables.audio.draw();

Subscribe to "click" event. Once "Delete" button is clicked stop the track and dispatch "ended" event

code

$('#' + stream.id + "-button").on('click', function(){
    //terminate stream
    console.log("terminate audio stream " + stream.id);
    let track = stream.getAudioTracks()[0];
    track.stop();
    track.dispatchEvent(new Event("ended"));
}).prop('disabled', true);

Subscribe to track's "ended" event and clean the table once track is ended

code

stream.getTracks()[0].onended = function() {
    controls.tables.audio.row(row).remove().draw();
}

Notify main script we have a new local track

code

trackCallback({
    stream: stream,
    encodings: track.encodings,
    source: track.source,
    type: track.type
});

5. Add new video tracks to controls¶

addVideoTrackRow() code

Function that will add new video tracks to controls and notify main script. This is the same as addAudioTrackRow function except it adds video

const addVideoTrackRow = async function(track) {
    const stream = await getMedia([track]);
    let button = '<button id="' + stream.id + '-button" class="btn btn-primary">Delete</button>';
    const row = controls.tables.video.row.add({
        source: track.source,
        width: track.width,
        height: track.height,
        codec: track.codec,
        action: button,
        stream: stream,
        encodings: track.encodings,
    }).node();
    controls.tables.video.draw();

    $('#' + stream.id + "-button").on('click', function(){
        //terminate stream
        console.log("terminate video stream " + stream.id);
        let track = stream.getVideoTracks()[0];
        track.stop();
        track.dispatchEvent(new Event("ended"));
    }).prop('disabled', true);
    stream.getTracks()[0].addEventListener("ended", function() {
        controls.tables.video.row(row).remove().draw();
    });
    trackCallback({
        stream: stream,
        encodings: track.encodings,
        source: track.source
    });
}

6. Format video encodings¶

format() code

Helper function to format video encodings so we can display them in the table nicely

const format = function(d) {
    if (!d.encodings) {
        return;
    }
    let details =  '<table cellpadding="5" cellspacing="0" border="0" style="padding-left:50px;">';
    d.encodings.forEach(function(encoding){
        details += '<tr>';
        for (const [key, value] of Object.entries(encoding)) {
            details += '<td>'+ key + '</td>'+
                '<td>'+ value + '</td>';
        }
        details += '</tr>';
    });
    details +='</table>';
    return details;
}

7. Audio and video track tables displaying¶

displayTables() code

const displayTables = async function() {
    // Add event listener for opening and closing details
    $('#videoTracksTableBody').on('click', 'td.details-control', function () {
        let tr = $(this).closest('tr');
        let row = controls.tables.video.row(tr);
        if (row.child.isShown()) {
            // This row is already open - close it
            row.child.hide();
            tr.removeClass('shown');
        } else {
            // Open this row
            row.child(format(row.data())).show();
            tr.addClass('shown');
        }
    });

    // Add preconfigured audio and video tracks
    for (const track of config.media.audio.tracks) {
        await addAudioTrackRow(track);
    }
    for (const track of config.media.video.tracks) {
        await addVideoTrackRow(track);
    }

    // Click event listener to add a new video track
    document.getElementById("addVideoTrack").addEventListener("click", function(e){
        let encodings = [];
        controls.tables.encodings.rows().every(function() {
            let encoding = this.data();
            encodings.push({
                rid: encoding.rid,
                active: encoding.active,
                maxBitrate: encoding.maxBitrate,
                scaleResolutionDownBy: encoding.resolutionScale
            })
        });
        let track = {
            source: controls.addVideoTrack.source.value,
            width: controls.addVideoTrack.width.value,
            height: controls.addVideoTrack.height.value,
            codec: controls.addVideoTrack.codec.value,
            encodings: encodings
        }
        addVideoTrackRow(track);
    });

    // Click event listener to remove video quality
    $("#videoTrackEncodingsTable").on("click", ".remove", function(){
        controls.tables.encodings.row($(this).parents('tr')).remove().draw();
    });

    // Click event listener to add video quality
    document.getElementById("addVideoTrackEncoding").addEventListener("click", function(){
        let button = '<button class="btn btn-primary remove">Delete</button>';
        controls.tables.encodings.row.add({
            rid: controls.addVideoEncoding.rid.value,
            active: controls.addVideoEncoding.active.value,
            maxBitrate: controls.addVideoEncoding.maxBitrate.value,
            resolutionScale: controls.addVideoEncoding.resolutionScale.value,
            action: button
        }).draw();
    });

    // Click event listener to add a new audio track
    document.getElementById("addAudioTrack").addEventListener("click", function(e){
        let encodings = [];
        let track = {
            source: controls.addAudioTrack.source.value,
            channels: controls.addAudioTrack.channels.value,
            encodings: encodings
        }
        addAudioTrackRow(track);
    });

}

7.1. Add handler to display/hide track details¶

code

Add open and close handler for video tracks details

$('#videoTracksTableBody').on('click', 'td.details-control', function () {
    let tr = $(this).closest('tr');
    let row = controls.tables.video.row(tr);
    if (row.child.isShown()) {
        // This row is already open - close it
        row.child.hide();
        tr.removeClass('shown');
    } else {
        // Open this row
        row.child(format(row.data())).show();
        tr.addClass('shown');
    }
});

7.2. Add audio and video tracks from configuration file to table¶

code

Add all configured audio and video tracks to the table

// Add preconfigured audio and video tracks
for (const track of config.media.audio.tracks) {
    await addAudioTrackRow(track);
}
for (const track of config.media.video.tracks) {
    await addVideoTrackRow(track);
}

7.3. Add video tracks to the table¶

code

Add all configured video tracks to the table

// Click event listener to add a new video track
document.getElementById("addVideoTrack").addEventListener("click", function(e){
    let encodings = [];
    controls.tables.encodings.rows().every(function() {
        let encoding = this.data();
        encodings.push({
            rid: encoding.rid,
            active: encoding.active,
            maxBitrate: encoding.maxBitrate,
            scaleResolutionDownBy: encoding.resolutionScale
        })
    });
    let track = {
        source: controls.addVideoTrack.source.value,
        width: controls.addVideoTrack.width.value,
        height: controls.addVideoTrack.height.value,
        codec: controls.addVideoTrack.codec.value,
        encodings: encodings
    }
    addVideoTrackRow(track);
});

7.4. Add audio tracks to the table¶

code

Add all configured audio tracks to the table

// Click event listener to add a new audio track
document.getElementById("addAudioTrack").addEventListener("click", function(e){
    let encodings = [];
    let track = {
        source: controls.addAudioTrack.source.value,
        channels: controls.addAudioTrack.channels.value,
        encodings: encodings
    }
    addAudioTrackRow(track);
});

8. Mute form elements¶

muteForm() code

Define helper function for muting forms

const muteForm = function(form) {
    for (const [key, value] of Object.entries(form)) {
        value.disabled = true;
    }
}

9. Unmute form elements¶

unmuteForm() code

Define helper function for unmuting forms

const unmuteForm = function(form) {
    for (const [key, value] of Object.entries(form)) {
        value.disabled = false;
    }
}

10. Mute entrance modal window inputs¶

muteInput() code

Define function that mutes entrance inputs

const muteInput = function() {
    muteForm(controls.entrance);
}

11. Create room configuration object¶

roomConfig() code

Define function that will assemble room config

const roomConfig = function() {
    let roomConfig = {
        url: controls.entrance.url.value,
        roomName: controls.entrance.roomName.value,
        pin: controls.entrance.roomPin.value,
        nickname: controls.entrance.nickName.value
    };
    if (config.room.failedProbesThreshold !== undefined) {
        roomConfig.failedProbesThreshold = config.room.failedProbesThreshold;
    }
    if (config.room.pingInterval !== undefined) {
        roomConfig.pingInterval = config.room.pingInterval;
    }
    return roomConfig;
}

12. Get local video tracks¶

getVideoStreams() code

Define function that will return all available local video tracks

const getVideoStreams = function() {
    let streams = [];
    controls.tables.video.rows().every(function(rowIdx, tableLoop, rowLoop) {
        let data = this.data();
        streams.push({
            stream: data.stream,
            encodings: data.encodings,
            source: data.source,
            type: data.type
        });
    });
    return streams;
}

13. Get local audio tracks¶

getAudioStreams() code

Define function that will return all available local audio tracks

const getAudioStreams = function() {
    let streams = [];
    controls.tables.audio.rows().every(function(rowIdx, tableLoop, rowLoop) {
        let data = this.data();
        streams.push({
            stream: data.stream,
            encodings: [],
            source: data.source
        });
    });
    return streams;
}

14. Handler to add video track to the table¶

code

The function passes a callback function to a new tracks

const onTrack = function(callback) {
    trackCallback = callback;
}

15. Export functions¶

code

Export functions for the script

return {
    muteInput: muteInput,
    roomConfig: roomConfig,
    displayTables: displayTables,
    getAudioStreams: getAudioStreams,
    getVideoStreams: getVideoStreams,
    onTrack: onTrack,
    cleanTables: cleanTables
}

16. Get media streams from WebRTC API¶

getMedia() code

Requests local media streams from the WebRTC API

const getMedia = async function(tracks) {
    //convert to constraints
    let screen = false;
    const constraints= {};
    tracks.forEach(function(track){
        if (track.source === "mic") {
            //audio
            constraints.audio = {};
            if (track.constraints) {
                constraints.audio = track.constraints;
            }
            constraints.audio.stereo = track.channels !== 1
            if (track.channels && track.channels === 2) {
                constraints.audio.echoCancellation = false;
                constraints.audio.googEchoCancellation = false;
            }
        } else if (track.source === "camera") {
            constraints.video = {};
            if (track.constraints) {
                constraints.video = track.constraints;
            }
            constraints.video.width = track.width;
            constraints.video.height = track.height;
        } else if (track.source === "screen") {
            constraints.video = {};
            if (track.constraints) {
                constraints.video = track.constraints;
            }
            constraints.video.width = track.width;
            constraints.video.height = track.height;
            screen = true;
        }
    });

    //get access to a/v
    let stream;
    if (screen) {
        stream = await navigator.mediaDevices.getDisplayMedia(constraints);
    } else {
        stream = await navigator.mediaDevices.getUserMedia(constraints);
    }
    return stream;
}