HTML5 Video - Percentage Loaded?

Does anyone know what event or property I need to query in order to get a percentage figure of the amount an HTML5 video has loaded? I want to draw a CSS styled "loaded" bar that's width represents this figure. Just like You Tube or any other video player.开发者_运维问答

So just like you tube a video will play even if the whole video hasn't loaded and give the user feedback on how much of the video has loaded and is left to load.

Just like the Red Bar on YouTube:

---

The progress event is fired when some data has been downloaded, up to three times per second. The browser provides a list of ranges of available media through the buffered property; a thorough guide to this is available on Media buffering, seeking, and time ranges on MDN.

Single load start

If the user doesn't skip through the video, the file will be loaded in one TimeRange and the buffered property will have one range:

------------------------------------------------------
|=============|                                      |
------------------------------------------------------
0             5                                      21
|             \_ this.buffered.end(0)
|
\_ this.buffered.start(0)

To know how big that range is, read it this way:

video.addEventListener('progress', function() {
    var loadedPercentage = this.buffered.end(0) / this.duration;
    ...
    // suggestion: don't use this, use what's below
});

Multiple load starts

If the user changes the playhead position while it's loading, a new request may be triggered. This causes the buffered property to be fragmented:

------------------------------------------------------
  |===========|                    |===========|     |
------------------------------------------------------
  1           5                    15          19    21
  |           |                    |            \_ this.buffered.end(1)
  |           |                     \_ this.buffered.start(1)
  |            \_ this.buffered.end(0)
   \_ this.buffered.start(0)

Notice how the number of the buffer changes.

Since it's no longer a contiguous loaded, the "percentage loaded" doesn't make a lot of sense anymore. You want to know what the current TimeRange is and how much of that is loaded. In this example you get where the load bar should start (since it's not 0) and where it should end.

video.addEventListener('progress', function() {
    var range = 0;
    var bf = this.buffered;
    var time = this.currentTime;

    while(!(bf.start(range) <= time && time <= bf.end(range))) {
        range += 1;
    }
    var loadStartPercentage = bf.start(range) / this.duration;
    var loadEndPercentage = bf.end(range) / this.duration;
    var loadPercentage = loadEndPercentage - loadStartPercentage;
    ...
});

---

The other awnsers didn't work for me so I started digging into this problem and this is what I came up with. The solutions uses jquery to make an progressbar.

function loaded()
{
    var v = document.getElementById('videoID');
    var r = v.buffered;
    var total = v.duration;

    var start = r.start(0);
    var end = r.end(0);

    $("#progressB").progressbar({value: (end/total)*100});      
}   

$('#videoID').bind('progress', function() 
{
    loaded();
}
);

I hope this helps others as well

---

Percentage fix for loaded string.. Output something like 99% loaded inside #loaded element...

function loaded() {
    var v = document.getElementById('videoID');
    var r = v.buffered;
    var total = v.duration;

    var start = r.start(0);
    var end = r.end(0);
    var newValue = (end/total)*100;
    var loader = newValue.toString().split(".");

    $('#loaded').html(loader[0]+' loaded...');

    $("#progress").progressbar({
        value: newValue     
    });    
}

---

I think best event to update the buffered progress bar is timeupdate. whenever time of the media is updated event is fired.

It gives buffered property which we can use like this

audio.addEventListener('timeupdate', function () {
    if (this.duration) {
         let range = 0;
         let bf = this.buffered;
         let time = this.currentTime;

         while (!(bf.start(range) <= time && time <= bf.end(range))) {
            range += 1;
         }
         let loadStartPercentage = bf.start(range) / this.duration;
         let loadEndPercentage = bf.end(range) / this.duration;
         let loadPercentage = (loadEndPercentage - loadStartPercentage) * 100;
         //Update your progressbar DOM here
    }
});

Best advantage of this event is this is fired when media is played. Whereas progress event is fired when media is downloaded and notified by browser.

So just like youtube, buffered percentage can only be shown when media is played

---

My answer is better than all of the other ones because you want to update buffer progress when the video is paused. This happens with the progress event. The time update event fires when progress fails, as it sometimes does.

$("#video").on("timeupdate progress", function(){
    var video = document.getElementById("video");
    var vidDur = video.duration;
    for(var i = 0; i <= vidDur; i++){
        var totBuffX = video.buffered.end(i);
        var perBuff = totBuffX/vidDur*100;
        $("#xVidBuffX").css("width", perBuff+"%");
    }
});

you only need video.buffered.end(i).