Keeping two YouTube videos in sync with each other
Your project is kinda interesting, that's why I decided to try to help you. I have never used the youtube API but I have tried some coding and it might be a start for you.
So here is the code I have tried and it seems to work quite well , it certainly needs some improvements ( I haven't tried to calculate the offset between the two played videos but letting them unmute shows the mismatch and it sounds legit)
Here we go :
Let's start with some html basics
<!DOCTYPE html><html> <head>We add an absolute positionning for the foreground player so it overlays the one playing the background video (for testing)
<style> #player2{position:absolute;left:195px;top:100px;} </style> </head><body>jQuery is used here to fade in/out the players (you'll see why below) but you can use basic JS
<script src="jquery-1.10.2.min.js"></script>The < iframes> (and video players) will replace these < div> tags.
<div id="player1"></div> <!-- Background video player --> <div id="player2"></div> <!-- Foreground video player --> <script>This code loads the IFrame Player API code asynchronously.
var tag = document.createElement('script'); tag.src = "https://www.youtube.com/iframe_api"; var firstScriptTag = document.getElementsByTagName('script')[0]; firstScriptTag.parentNode.insertBefore(tag, firstScriptTag);This function creates the < iframes> (and YouTube players) after the API code downloads. Note the callback functions : onPlayer1Ready and onPlayer1StateChange
var player1; var player2; function onYouTubeIframeAPIReady() { player1 = new YT.Player('player1', { height: '780', width: '1280', videoId: 'M7lc1UVf-VE', playerVars: { 'autoplay': 0, 'controls': 0 }, events: { 'onReady': onPlayer1Ready, 'onStateChange': onPlayer1StateChange } }); player2 = new YT.Player('player2', { height: '390', width: '640', videoId: 'M7lc1UVf-VE', events: { 'onReady': onPlayer2Ready, 'onStateChange': onPlayer2StateChange } }); } var player1Ready = false; var player2Ready = false;So now is the interesting part of the code. The main issue in your project of sync is linked to the fact that videos need to be buffered before launching them. Actually the API doesn't provide any kind of intuitive function to preload the videos (due to bandwidth issues (client and server side). So we have to get a bit tricky.
The steps to preload a video are the following:
- Hide the player so the next steps aren't visible for the user);
- Mute the player (
player.mute():Void); - Emulate a jump in timeline to start the buffering (
player.seekTo(seconds:Number, allowSeekAhead:Boolean):Void); - Wait for a state change event equal to
YT.PlayerState.PLAYING; - Pause the video (
player.pauseVideo():Void); - Rewind the video with
player.seekTo(seconds:Number, allowSeekAhead:Boolean):Void; - Unmute the player (
player.unMute():Void); - Show the player.
You have to preload your two videos.
var preloading1 = false; var preloading2 = false;The API will call these functions when the video players are ready.
function onPlayer1Ready(event) { player1Ready = true; preloading1 = true; // Flag the player 1 preloading player1.mute(); // Mute the player 1 $( "#player1" ).hide(); // Hide it player1.seekTo(1); // Start the preloading and wait a state change event } function onPlayer2Ready(event) { player2Ready = true; // The foreground video player is not preloaded here }The API calls this function when the background video player's state changes.
function onPlayer1StateChange(event) { if (event.data == YT.PlayerState.PLAYING ) { if(preloading1) { prompt("Background ready"); // For testing player1.pauseVideo(); // Pause the video player1.seekTo(0); // Rewind player1.unMute(); // Comment this after test $( "#player1" ).show(); // Show the player preloading1 = false; player2Ready = true; preloading2 = true; // Flag for foreground video preloading player2.mute(); //$( "#player2" ).hide(); player2.seekTo(1); // Start buffering and wait the event } else player2.playVideo(); // If not preloading link the 2 players PLAY events } else if (event.data == YT.PlayerState.PAUSED ) { if(!preloading1) player2.pauseVideo(); // If not preloading link the 2 players PAUSE events } else if (event.data == YT.PlayerState.BUFFERING ) { if(!preloading1) { player2.pauseVideo(); // If not preloading link the 2 players BUFFERING events } } else if (event.data == YT.PlayerState.CUED ) { if(!preloading1) player2.pauseVideo(); // If not preloading link the 2 players CUEING events } else if (event.data == YT.PlayerState.ENDED ) { player2.stopVideo(); // If not preloading link the 2 players ENDING events } }The API calls this function when the foreground video player's state changes.
function onPlayer2StateChange(event) { if (event.data == YT.PlayerState.PLAYING ) { if(preloading2) { //prompt("Foreground ready"); player2.pauseVideo(); // Pause the video player2.seekTo(0); // Rewind player2.unMute(); // Unmute preloading2 = false; $( "#player2" ).show(50, function() {Here is a part of the code that acts strangely. Uncommenting the line below will make the sync quite bad,but if you comment it, you will have to click twice on the PLAY button BUT the sync will look way better.
//player2.playVideo(); }); } else player1.playVideo(); } else if (event.data == YT.PlayerState.PAUSED ) { if(/*!preloading1 &&*/ !preloading2) player1.pauseVideo(); } else if (event.data == YT.PlayerState.BUFFERING ) { if(!preloading2) { player1.pauseVideo(); //player1.seekTo(... // Correct the offset here } } else if (event.data == YT.PlayerState.CUED ) { if(!preloading2) player1.pauseVideo(); } else if (event.data == YT.PlayerState.ENDED ) { player1.stopVideo(); } } </script> </body></html>Note that the views might not be counted with this code.
If you want the code without the explanations you can go here : http://jsfiddle.net/QtBlueWaffle/r8gvX/1/
2016 UpdateLive Preview
Hope this helps.