JS 用CANVAS自定义VIDEO播放器

概述

HTML5用规范的VIDEO标签取代了以往需要借助外部控件进行视频播放的历史（如Flash播放器），实现了浏览器无插件统一视频播放标准。
统一的VIDEO标签也有其自身局限，如VIDEO标签在不同浏览器实现时层级控制不尽相同，播放器外观也在不同浏览器表现不一，虽然通过浏览器私有CSS可以定义风格，但其可定义风格是非常有限的，等等问题。
为了实现客户定制统一风格视频播放器，HTML网页可以借助CANVAS进行自定义VIDEO绘制。

CANVAS绘制核心代码

let canvas = this.canvas;
var ctx = canvas.getContext('2d');
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.drawImage(this.video, 0, 0, canvas.width, canvas.height); // this.video = document.getElementById(videoId);

VIDEO标签可以和普通IMG一样进行绘制；
VIDEO仅作与服务器通讯、视频下载、解码等功能，显示和UI则通过CANVAS和其他HTML元素替代。

播放器代码

/*
 * singleplayer.js
 * 为了优化性能，对于页面中多于一个video标签，但同时只有一个VIDEO点播的，SinglePlayer仅使用一个VIDEO标签
 * 第一个SinglePlayer保留VIDEO标签，并将VIDEO设置为1x1（苹果浏览器可能要求VIDEO不能隐藏，否则直接冻结优化掉视频流）
 * if (null == g_SinglePlayer) { // 仅保留第一个VIDEO标签，并将尺寸设置为1x1
    $(this.video).css("width", "1px").css("height", "1px");
    $(this.video).parent().append(html);
    g_SinglePlayer = this;
 }
 else { // 用SinglePlayer替换VIDEO标签
    $(this.video).parent().html(html);
    this.videoId = g_SinglePlayer.playerId;
    this.video = g_SinglePlayer.video;
    if (!this.isFullPlayer) {
        g_VidepPlayerList.push(this);
    }
 }
 * 对于部分浏览器，设置video.src则会自动缓存视频，即使通过DOM操作删除video，也不会导致已经缓存下载的视频流取消缓存和下载
 * SinglePlayer通过自定义videoSource属性替代src属性，在激活对应player时再用videoSource值设置src
 * */
var g_VidepPlayerList = new Array();
var g_FullscreenPlayer = null;
var g_CurrentPlayer = null;
var g_SinglePlayer = null;
var g_ActivedPlayer = null;
var g_PlayerClicked = false;
class SinglePlayer {
    constructor(videoId, videoWidth = 960, videoHeight = 540, full = false) {
        this.videoId = videoId;
        this.videoWidth = videoWidth;
        this.videoHeight = videoHeight;
        this.isVisibled = true;
        this.isFullPlayer = full;
        this.playerId = videoId   "_player";
        this.canvasId = videoId   "_canvas";
        this.controlsId = videoId   "_controls";
        this.timeId = videoId   "_time";
        this.playId = videoId   "_play";
        this.muteId = videoId   "_mute";
        this.seekId = videoId   "_seek";
        this.fullscreenId = videoId   "_fullscreen";
        this.isSeeking = false;
        this.isFirstPlayed = false;

        this.video = document.getElementById(videoId);
        if (null == this.video) {
            console.log("没有找到视频["   videoId   "]");
        }
        this.poster = new Image();
        this.poster.src = $(this.video).attr("poster");
        this.videoSource = $(this.video).attr("videoSource");
        this.canvas = null;
        this.player = null;
        this.isFullscreen = false;
        this.isPlaying = false;
        this.idletime = 0;
        this.lasttimestamp = 0;
        this.frames = 0;
        this.frametime = 0;
        this.fps = 0;

        this.touchX = null;
        this.touchY = null;
        this.seekStart = 0;
        this.message = "";

        var html = "";
        if (!full) {
            html  = '<div id="'   this.playerId   '" class="canvas_player" style="position:absolute;width:100%;">';
            html  = '  <canvas class="canvasplayer_canvas" id="'   this.canvasId   '" width="'   this.videoWidth   '" height="'   this.videoHeight   '" style="width:100%;"></canvas>';
            html  = '  <div class="canvasplayer_controls" id="'   this.controlsId   '" style="position:absolute;width:100%;height:20%;bottom:1.6%;left:0px;background-image:url(\'img/videoplayer/backgnd.png\');transform: translateZ(10px);z-order:10">';
            html  = '    <div class="canvasplayer_controls" style="position:absolute;width:85%;height:30%;left:10%;top:40%"><input type="range" min="0.0" max="1.0" value="0.0" step="0.01" id="'   this.seekId   '" style="width:100%;height:15%;::-webkit-slider-thumb{width:10px;height:10px;}" /></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.timeId   '" style="position:absolute;width:60%;left:10%;top:15%;text-align:left;"><span style="color:white;text-align:left;font-size:50%">0:00 / 0:00</span></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.playId   '" style="position:absolute;width:3%;left:5%;top:39%;padding-top:4px;"><img src="https://blog.csdn.net/qq_31042143/article/details/img/videoplayer/play.png" /></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.muteId   '" style="position:absolute;width:3%;left:80%;top:15%"><img src="https://blog.csdn.net/qq_31042143/article/details/img/videoplayer/mute.png" /></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.fullscreenId   '" style="position:absolute;width:3%;left:90%;top:15%"><img src="https://blog.csdn.net/qq_31042143/article/details/img/videoplayer/fullscreen.png" /></div>';
            html  = '  </div>';
            html  = '</div>';
        }
        else {
            html  = '<div id="'   this.playerId   '" class="canvas_player" style="position:absolute;width:100%;left:0px;top:0px;">';
            html  = '  <canvas class="canvasplayer_canvas" id="'   this.canvasId   '" width="'   this.videoWidth   '" height="'   this.videoHeight   '" style="width:100%;height:'   window.innerWidth   'px"></canvas>';
            html  = '  <div class="canvasplayer_controls" id="'   this.controlsId   '" style="position:absolute;width:100%;height:20%;bottom:0px;left:0px;background-image:url(\'img/videoplayer/backgnd.png\');transform: translateZ(10px);z-order:10">';
            html  = '    <div class="canvasplayer_controls" style="position:absolute;width:85%;height:30%;left:10%;bottom:20%"><input type="range" min="0.0" max="1.0" value="0.0" step="0.01" id="'   this.seekId   '" style="width:100%;height:15%" /></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.timeId   '" style="position:absolute;width:60%;left:10%;top:15%;text-align:left;"><span style="color:white;text-align:left;font-size:50%">0:00 / 0:00</span></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.playId   '" style="position:absolute;width:3%;left:5%;top:50%"><img src="https://blog.csdn.net/qq_31042143/article/details/img/videoplayer/play.png" /></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.muteId   '" style="position:absolute;width:3%;left:80%;top:15%"><img src="https://blog.csdn.net/qq_31042143/article/details/img/videoplayer/mute.png" /></div>';
            html  = '    <div class="canvasplayer_controls" id="'   this.fullscreenId   '" style="position:absolute;width:3%;left:90%;top:15%"><img src="https://blog.csdn.net/qq_31042143/article/details/img/videoplayer/unfullscreen.png" /></div>';
            html  = '  </div>';
            html  = '</div>';
            g_FullscreenPlayer = this;
        }
        if (null == g_SinglePlayer) {
            $(this.video).css("width", "1px").css("height", "1px");
            $(this.video).parent().append(html);
            g_SinglePlayer = this;
        }
        else {
            $(this.video).parent().html(html);
            this.videoId = g_SinglePlayer.playerId;
            this.video = g_SinglePlayer.video;
            if (!this.isFullPlayer) {
                g_VidepPlayerList.push(this);
            }
        }

        $("#"   this.canvasId).click(function () {
            if (!SinglePlayer.TestPlayerClicked()) return;
            var id = $(this).attr("id");
            var player = SinglePlayer.getPlayerByCanvasId(id);
            if (!player.isFullPlayer && SinglePlayer.GetActivePlayer() != player) {
                SinglePlayer.ActivePlayer(player);
            }
            player.showcontrols();
            if (!player.isFirstPlayed) {
                player.play();
            }
        });
        $("#"   this.playId).click(function () {
            if (!SinglePlayer.TestPlayerClicked()) return;
            var playerId = $(this).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            if (!player.isFullPlayer && SinglePlayer.GetActivePlayer() != player) {
                SinglePlayer.ActivePlayer(player);
            }
            if (player.isPlaying) {
                player.pause();
            }
            else {
                player.play();
            }
        });
        $("#"   this.muteId).click(function () {
            if (!SinglePlayer.TestPlayerClicked()) return;
            var playerId = $(this).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            player.mute(!player.isMuted());
            player.updateUI();
        });
        $("#"   this.seekId).change(function () {
            if (!SinglePlayer.TestPlayerClicked()) return;
            var playerId = $(this).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            player.seek($(this).val());
        });
        var seek = document.getElementById(this.seekId);
        seek.addEventListener('touchstart', function (event) {
            if (!SinglePlayer.TestPlayerClicked()) return;
            //event.preventDefault();
            var playerId = $(seek).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            player.isSeeking = true;
            player.showcontrols();
            if (event.targetTouches.length == 1) {
                var touch = event.targetTouches[0];
                player.touchX = touch.clientX;
                player.touchY = touch.clientY;
                player.seekStart = new Number($(seek).val());
            }
        });
        seek.addEventListener('touchmove', function (event) {
            if (!SinglePlayer.TestPlayerClicked()) return;
            //event.preventDefault();
            var playerId = $(seek).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            player.showcontrols();
            player.isSeeking = true;
            if (event.targetTouches.length == 1) {
                var touch = event.targetTouches[0];
                var dx = touch.clientX - player.touchX;
                var dy = touch.clientY - player.touchY;
                dy /= $(seek).outerWidth(false);
                player.message = "setPos("   player.seekStart   dy   ")";
                $(seek).val(player.seekStart   dy)
                player.seek(player.seekStart   dy);
            }
        });
        seek.addEventListener('touchend', function (event) {
            if (!SinglePlayer.TestPlayerClicked()) return;
            //event.preventDefault();
            // alert("touchend at "   $(seek).closest('.canvas_player').attr("id")   " with "   event.targetTouches.length);
            if (event.targetTouches.length == 0) {
                var playerId = $(seek).closest('.canvas_player').attr("id");
                var player = SinglePlayer.getPlayerByPlayerId(playerId);
                setTimeout(function () {
                    player.isSeeking = false;
                }, 100, this)
            }
        });
        $("#"   this.seekId).mousedown(function () {
            if (!SinglePlayer.TestPlayerClicked()) return;
            var playerId = $(this).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            player.isSeeking = true;
        });
        $("#"   this.seekId).mouSEO（(Search Engine Optimization)）ut(function () {
            if (!SinglePlayer.TestPlayerClicked()) return;
            var playerId = $(this).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            player.isSeeking = false;
        });
        $("#"   this.fullscreenId).click(function () {
            if (!SinglePlayer.TestPlayerClicked()) return;
            var playerId = $(this).closest('.canvas_player').attr("id");
            var player = SinglePlayer.getPlayerByPlayerId(playerId);
            console.log("全屏按钮["   this.isFullPlayer   "]");
            if (!player.isFullPlayer) {
                player.fullscreen();
            }
            else {
                SinglePlayer.ExitFullscreen();
            }
        });

        this.canvas = document.getElementById(this.canvasId);
        this.player = document.getElementById(this.playerId);
    }
    static getPlayerByPlayerId(playerId) {
        if (null != g_FullscreenPlayer && g_FullscreenPlayer.playerId == playerId) {
            return g_FullscreenPlayer;
        }
        for (var i = 0; i < g_VidepPlayerList.length;   i) {
            if (g_VidepPlayerList[i].playerId == playerId) {
                return g_VidepPlayerList[i];
            }
        }
        return null;
    }
    static getPlayerByVideoId(videoId) {
        if (null != g_FullscreenPlayer && g_FullscreenPlayer.videoId == videoId) {
            return g_FullscreenPlayer;
        }
        for (var i = 0; i < g_VidepPlayerList.length;   i) {
            if (g_VidepPlayerList[i].videoId == videoId) {
                return g_VidepPlayerList[i];
            }
        }
        return null;
    }
    static getPlayerByCanvasId(canvasId) {
        if (null != g_FullscreenPlayer && g_FullscreenPlayer.canvasId == canvasId) {
            return g_FullscreenPlayer;
        }
        for (var i = 0; i < g_VidepPlayerList.length;   i) {
            if (g_VidepPlayerList[i].canvasId == canvasId) {
                return g_VidepPlayerList[i];
            }
        }
        return null;
    }
    static toTime(seconds) {
        if (isNaN(seconds)) {
            return "0:00";
        }
        else {
            var minutes = parseInt(seconds / 60);
            seconds = parseInt(seconds - minutes * 60);
            if (seconds < 10) {
                return minutes   ":0"   seconds;
            }
            else {
                return minutes   ":"   seconds;
            }
        }
    }
    static isNullOrEmpty(str) {
        return null == str || undefined == str || "" == str || "undefined" == str;
    }
    updateUI() {
        if (this.isMuted()) {
            $("#"   this.muteId).find("img").attr("src", "img/videoplayer/mute.png");
        }
        else {
            $("#"   this.muteId).find("img").attr("src", "img/videoplayer/unmute.png");
        }
        if (!this.isPlaying) {
            $("#"   this.playId).find("img").attr("src", "img/videoplayer/play.png");
        }
        else {
            $("#"   this.playId).find("img").attr("src", "img/videoplayer/pause.png");
        }
        if (null == g_FullscreenPlayer) {
            $("#"   this.fullscreenId).hide();
        }
        else {
            $("#"   this.fullscreenId).show();
        }
    }
    play() {
        if (this.isFirstPlayed) {

        }
        this.video.play();
        this.isPlaying = true;
        this.isFirstPlayed = true;
    }
    pause() {
        this.video.pause();
        this.isPlaying = false;
    }
    showcontrols() {
        this.idletime = 0;
        $("#"   this.controlsId).show();
    }
    mute(muted) {
        this.video.muted = muted;
    }
    isMuted() {
        return this.video.muted;
    }
    seek(pos) {
        if (!isNaN(this.video.currentTime) && !isNaN(this.video.duration)) {
            this.video.currentTime = pos * this.video.duration;
        }
    }
    fullscreen() {
        if (null != g_FullscreenPlayer) {
            this.isFullscreen = true;
            g_CurrentPlayer = this;
            g_FullscreenPlayer.setVisible(true);
            g_FullscreenPlayer.isPlaying = this.isPlaying;
            g_FullscreenPlayer.isMuted = this.isMuted;
            g_FullscreenPlayer.isFirstPlayed = this.isFirstPlayed;
        }
    }
    static ExitFullscreen() {
        console.log("ExitFullscreen");
        if (null != g_FullscreenPlayer && null != g_CurrentPlayer) {
            g_CurrentPlayer.isPlaying = g_FullscreenPlayer.isPlaying;
            g_CurrentPlayer.isMuted = g_FullscreenPlayer.isMuted;
            g_CurrentPlayer.isFirstPlayed = g_FullscreenPlayer.isFirstPlayed;;
            g_CurrentPlayer.isFullscreen = false;

            g_FullscreenPlayer.setVisible(false);

            g_CurrentPlayer = null;
        }
    }
    setVisible(visible = true) {
        this.isVisibled = visible;
        if (visible) {
            $(this.player).parent().show();
            this.showcontrols();
        }
        else {
            $(this.player).parent().hide();
        }
    }
    nextFrame() {

    }
    render(timestamp) {
        var ticks = (timestamp - this.lasttimestamp) / 1000;
        this.lasttimestamp = timestamp;
        this.frametime  = ticks;
        if (this.frametime >= 0.1) {
            this.nextFrame();
            this.frametime = 0;
        }
          this.frames;
        this.fps = this.frames * 1000 / this.timestamp;
        this.idletime  = ticks;

        // 绘制视频
        let canvas = this.canvas;
        var ctx = canvas.getContext('2d');
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        ctx.fillStyle = "black";
        ctx.fillRect(0, 0, canvas.width, canvas.height);
        var vh = this.video.videoWidth;
        var vw = this.video.videoHeight;
        var aspect = vw / vh;
        var height = canvas.width * aspect;
        var width = canvas.width;
        var top = (canvas.height - height) / 2;
        var left = 0;
        if (top < 0) {
            width = canvas.height / aspect;
            height = canvas.height;
            top = 0;
            left = (canvas.width - width) / 2
        }
        ctx.drawImage(this.video, left, top, width, height);

        if (!this.isFirstPlayed) {
            if (null != this.poster) {
                var vh = this.poster.width;
                var vw = this.poster.height;
                var aspect = vw / vh;
                var height = canvas.width * aspect;
                var width = canvas.width;
                var top = (canvas.height - height) / 2;
                var left = 0;
                if (top < 0) {
                    width = canvas.height / aspect;
                    height = canvas.height;
                    top = 0;
                    left = (canvas.width - width) / 2
                }
                ctx.drawImage(this.poster, left, top, width, height);
            }
        }
        var text = timestamp   " - "   this.message;
        ctx.font = "30px Verdana";
        ctx.fillStyle = "red";
        // ctx.fillText(text, canvas.width * 0.05, canvas.height * 0.05);

        var text = SinglePlayer.toTime(this.video.currentTime)   "&nbsp;\/&nbsp;"   SinglePlayer.toTime(this.video.duration);
        $("#"   this.timeId).find("span").html(text);
        if (!this.isSeeking) {
            var seek = 0;
            if (!isNaN(this.video.currentTime) && !isNaN(this.video.duration)) {
                seek = this.video.currentTime / this.video.duration
            }
            $("#"   this.seekId).val(seek);
        }
        if (this.idletime > 3) {
            $("#"   this.controlsId).hide();
        }
    }
    static RenderPlayers(timestamp) {
        if (null != g_FullscreenPlayer && g_FullscreenPlayer.isVisibled) {
            g_FullscreenPlayer.render(timestamp);
        }
        else {
            for (var i = 0; i < g_VidepPlayerList.length;   i) {
                var player = g_VidepPlayerList[i];
                if (player.isVisibled) {
                    player.render(timestamp);
                }
            }
        }
        window.requestAnimationFrame((timestamp) => SinglePlayer.RenderPlayers(timestamp));
    }
    static Init() {
        if (null != g_FullscreenPlayer) {
            g_FullscreenPlayer.setVisible(false);
        }
        window.requestAnimationFrame((timestamp) => SinglePlayer.RenderPlayers(timestamp));
    }
    static ActivePlayer(player) {
        if (player == g_FullscreenPlayer) {
            console.log("不能将全屏播放器设置为激活");
            return;
        }
        for (var i = 0; i < g_VidepPlayerList.length;   i) {
            if (g_VidepPlayerList[i] != player) {
                g_VidepPlayerList[i].setVisible(false)
            }
        }
        if (null != g_ActivedPlayer) {
            g_ActivedPlayer.pause();
        }
        g_ActivedPlayer = player;
        if (null != g_ActivedPlayer) {
            g_ActivedPlayer.setVisible(true);
            g_SinglePlayer.video.pause();
            $(g_SinglePlayer.video).attr("src", g_ActivedPlayer.videoSource);
            g_ActivedPlayer.isFirstPlayed = false;
            g_ActivedPlayer.isPlaying = false;
            g_ActivedPlayer.updateUI();
        }
    }
    static GetActivePlayer() {
        return g_ActivedPlayer;
    }
    static IsPlayerClicked() {
        return g_PlayerClicked;
    }
    static TestPlayerClicked() {
        console.log("g_PlayerClicked="   g_PlayerClicked);
        if (g_PlayerClicked) {
            return false;
        }
        g_PlayerClicked = true;
        setTimeout(function () {
            g_PlayerClicked = false;
        }, 100, null);
        return true;;
    }
}

使用页面HTML代码

    <!-- 视频 -->
    <div class="popCon popCon1">
        <div class="videoPop">
            <video videoSource="video/bird_family1.mp4" id="myVideo1" poster="video/bird_family1.JPG" controls></video>
        </div>
    </div>
    <div class="popCon popCon2">
        <div class="videoPop">
            <video videoSource="video/bird_family2.mp4" id="myVideo2" poster="video/bird_family2.JPG" controls></video>
        </div>
    </div>
    <div class="popCon popCon3">
        <div class="videoPop">
            <video videoSource="video/bird_family3.mp4" id="myVideo3" poster="video/bird_family3.JPG" controls></video>
        </div>
    </div>
    <div class="popCon popCon4">
        <div class="videoPop">
            <video videoSource="video/bird_family4.mp4" id="myVideo4" poster="video/bird_family4.JPG" controls></video>
        </div>
    </div>

    <div id="realplayer"
        style="position:absolute;width:1px;height:1px;z-index:-1;transform:translateZ(-1px);left:-10000px">
        <video id="realVideo" class="full_player" poster="video/casa_v1.JPG" webkit-playsinline="true"
            playsinline="true" x5-video-player-type="h5" x5-video-orientation="landscape" controls></video>
    </div>
    <div id="fullplayer"
        style="position:absolute;width:100%;height:100vh;z-index:999;transform:translateZ(999px);left:0px;top:0px;display:none;">
        <video id="fullVideo" class="full_player" poster="video/casa_v1.JPG" webkit-playsinline="true"
            playsinline="true" x5-video-player-type="h5" x5-video-orientation="landscape" controls></video>
    </div>

使用页面JS代码

	// 先创建真实播放器和全屏播放器
  new SinglePlayer("realVideo", window.innerHeight, window.innerWidth, false);
  new SinglePlayer("fullVideo", window.innerHeight, window.innerWidth, true);

	// 创建每个VIDEO对应播放器（不会生成CANVAS）
  var index = 0;
  $("video").each(function (index, element) {
      if (!$(element).hasClass("full_player")) {
          $(element).attr("id", "myVideo_"   index);
          new SinglePlayer("myVideo_"   index, 960, 540, false);
          index  ;
      }
  });

	// 切换slider时激活对应视频
  function SlideVideo(pop) {
      var domPlayer = $("."   pop).find(".canvas_player");
      var playerId = $(domPlayer).attr("id");
      var player = SinglePlayer.getPlayerByPlayerId(playerId);
      if (null != player) {
          SinglePlayer.ActivePlayer(player);
          console.log("切换视频成功["   playerId   "]")
      }
      else {
          console.log("切换视频失败["   playerId   "]")
      }
  }

使用示例

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