Overview

The player shows how to convert stream published on WCS server to HLS and play it in browser using HLS.js. HLS segments cut starts automatically when stream is requested by HLS URL, for example `https://test1.flashphoner.com:8445/test/test.m3u8` on the screenshot below

Since build 2.0.244, the example supports the following parameters:

llhls - enable Low Latency HLS support: false or true
src - stream full HLS URL to play, should be encoded with URI, for example https%3A%2F%2Ftest1.flashphoner.com%3A8445%2Ftest%2Ftest.m3u8
autoplay - automatically play the HLS URL, in this case all the input fields and buttons are hidden: false (by default) or true

The player URL example with parameters as displayed on the screenshot above (the link is available in Permalink field)

https://test1.flashphoner.com:8444/client2/examples/demo/streaming/hls-js-player/hls-js-player.html?llhls=false&src=https%3A%2F%2Ftest1.flashphoner.com%3A8445%2Ftest-HLS-ABR-STREAM%2Ftest-HLS-ABR-STREAM.m3u8

The player URL example with autoplay enabled

https://test1.flashphoner.com:8444/client2/examples/demo/streaming/hls-js-player/hls-js-player.html?llhls=false&src=https%3A%2F%2Ftest1.flashphoner.com%3A8445%2Ftest-HLS-ABR-STREAM%2Ftest-HLS-ABR-STREAM.m3u8&autoplay=true

In this case the stream should be played automatically with audio muted. A viewer should use a loud slider in the player interface to unmute audio.

The code of the example

The source code can be accessed on server by the following path:

/usr/local/FlashphonerWebCallServer/client2/examples/demo/streaming/hls-js-player

hls-js-player.css - player page styles file
hls-js-player.html - player page
hls.js - player script (https://github.com/video-dev/hls.js/, Apache License Version 2.0)
hls-js-player.js - player launch script
hls.min.js - player script (minimized)
../hls-player/player-page.html - common player page elements for three HLS playback examples

The example can be tested using the fiollowing URL:

https://host:8888/client2/examples/demo/streaming/hls-js-player/hls-js-player.html

Where host is WCS server address

Analyzing the code

To analyze the code get hls-js-player.js file version with hash b19f637 which is available here and can be downloaded in build 2.0.248.

1. Loading the player page

code

const loadPlayerPage = function() {
    loadPage("../hls-player/player-page.html", "playerPage", initPage );
}

2. The player HTML page initializing

code

If browser does not support MSE, player will not be initialized and a warning will be displayed

const initPage =  function() {
    if (playSrc) {
        setValue("fullLink", decodeURIComponent(playSrc));
    } else if (autoplay) {
        console.warn("No HLS URL set, autoplay disabled");
        autoplay = false;
    }
    if (llHlsEnabled) {
        setCheckbox("llHlsEnabled", llHlsEnabled);
    }
    remoteVideo = document.getElementById('remoteVideo');
    if (Hls.isSupported()) {
        console.log("Using HLS.JS " + Hls.version);
        if (autoplay) {
            // There should not be any visible item on the page unless player
            hideAllToAutoplay();
            // The player should use all available page width
            setUpPlayerItem(true);
            // The player should be muted to automatically start playback
            initVideoPlayer(remoteVideo, true);
            playBtnClick();
        } else {
            setText("header", "HLS.JS Player Minimal");
            showItem("llHlsMode");
            displayCommonItems();
            setUpButtons();
            enablePlaybackStats();
            // The player should have a maximum fixed size
            setUpPlayerItem(false);
            // The player can be unmuted because user should click Play button
            initVideoPlayer(remoteVideo, false);
        }
    } else {
        setText("notifyFlash", "Your browser doesn't support MSE technology required to play video");
        disableItem("applyBtn");
        toggleInputs(false);
    }
}

3. Video tag initializing to play

code

const initVideoPlayer = function(video, muted) {
    if (video) {
        video.style.backgroundColor = "black";
        video.muted = muted;
    }
}

4. HLS stream URL forming

code

If authentication key and token are set, they will be included to stream URL

const getVideoSrc = function(src) {
    let videoSrc = src;
    if (validateForm()) {
        let streamName = getValue('playStream');
        streamName = encodeURIComponent(streamName);
        videoSrc = getValue("urlServer") + '/' + streamName + '/' + streamName + '.m3u8';
        let key = getValue('key');
        let token = getValue("token");
        if (key.length > 0 && token.length > 0) {
            videoSrc += "?" + key + "=" + token;
        }
    }
    setValue("fullLink", videoSrc);
    return videoSrc;
}

5. HLS.js player configuration

code

const getHlsConfig = function(llHlsEnabled) {
    let config = {
        lowLatencyMode: false,
        enableWorker: true,
        backBufferLength: 90,
        manifestLoadingTimeOut: 15000
    };
    console.log("Low Latency HLS: "+llHlsEnabled)
    if(llHlsEnabled) {
        // Here we configure HLS.JS for lower latency
        config = {
           lowLatencyMode: llHlsEnabled,
           enableWorker: true,
           backBufferLength: 90,
           liveBackBufferLength: 0,
           liveSyncDuration: 0.5,
           liveMaxLatencyDuration: 5,
           liveDurationInfinity: true,
           highBufferWatchdogPeriod: 1,
           manifestLoadingTimeOut: 15000
        };
    }
    return config;
}

6. Player launching

Hls.on(), Hls.loadSource(), Hls.attachMedia(), HTMLVideoElement.onplaying() code

const playBtnClick = function() {
    let videoSrc = getVideoSrc(getValue("fullLink"));
    if (videoSrc) {
        llHlsEnabled = getCheckbox("llHlsEnabled");
        hlsPlayer = new Hls(getHlsConfig(llHlsEnabled));
        hlsPlayer.on(Hls.Events.MANIFEST_PARSED, function() {
            console.log("Play with HLS.js");
            remoteVideo.play();
            initQualityLevels(hlsPlayer);
        });
        remoteVideo.onplaying = () => {
            console.log("playing event fired");
            displayPermalink(videoSrc);
            displayQualitySwitch();
        }
        hlsPlayer.loadSource(videoSrc);
        hlsPlayer.attachMedia(remoteVideo);
        onStarted();            
    }
}

7. Get available qualities list

Hls.levels code

const initQualityLevels = function(player) {
    if (player) {
        let qualityDiv = document.getElementById("qualityBtns");
        let qualityLevel;
        for (let i = 0; i < player.levels.length; i++) {
            qualityLevel = QualityLevel(player, player.levels[i].height, i, qualityDiv);
            qualityLevels.push(qualityLevel);
        }
        if (qualityLevels.length) {
            qualityLevel = QualityLevel(player, QUALITY_AUTO, -1, qualityDiv);
            qualityLevels.push(qualityLevel);
        }
    }
}

8. Quality button click action

Hls.currentLevel code

const qualityBtnClick = function(button, player, index) {
    if (player) {
        player.currentLevel = index;
    }
    button.style.color = QUALITY_COLORS.SELECTED;
    qualityLevels.forEach(item => {
        if (item.button.id !== button.id) {
            item.button.style.color = QUALITY_COLORS.AVAILABLE
        }
    });
}

9. Playback stopping

code

const stopBtnClick = function() {
    if (hlsPlayer != null) {
        console.log("Stop HLS segments loading");
        hlsPlayer.stopLoad();
        hlsPlayer = null;
    }
    if (remoteVideo != null) {
        console.log("Stop HTML5 player");
        remoteVideo.pause();
        remoteVideo.currentTime = 0;
        remoteVideo.removeAttribute('src');
        remoteVideo.load();
    }
    onStopped();
}

10. Dispose qualities list when player is stopped

code

const disposeQualityLevels = function() {
    qualityLevels.forEach(level => {
        if (level.button) {
            level.button.remove();
        }
    });
    qualityLevels = [];
}

11. Getting an available playback statistics from HTML5 video tag

HTML5Stats code

const PlaybackStats = function(interval) {
    const playbackStats = {
        interval: interval || STATS_INTERVAL,
        timer: null,
        stats: null,
        start: function() {
            let video = remoteVideo;

            playbackStats.stop();
            stats = HTML5Stats(video);
            playbackStats.timer = setInterval(playbackStats.displayStats, playbackStats.interval);
            setText("videoWidth", "N/A");
            setText("videoHeight", "N/A");
            setText("videoRate", "N/A");
            setText("videoFps", "N/A");
            showItem("stats");
        },
        stop: function() {
            if (playbackStats.timer) {
                clearInterval(playbackStats.timer);
                playbackStats.timer = null;
            }
            playbackStats.stats = null;
            hideItem("stats");
        },
        displayStats: function() {
            if (stats.collect()) {
                let width = stats.getWidth();
                let height = stats.getHeight();
                let bitrate = stats.getBitrate();
                let fps = stats.getFps();

                setText("videoWidth", width);
                setText("videoHeight", height);

                if (bitrate !== undefined) {
                    setText("videoRate", Math.round(bitrate));
                }
                if (fps !== undefined) {
                    setText("videoFps", fps.toFixed(1));
                }
            }
        }
    };
    return playbackStats;
}

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Overview

The code of the example

Analyzing the code

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HLS.js Player

Overview

The code of the example

Analyzing the code