html5 video playing twice (audio doubled) with JQuery .append()

Question

Huge WTF that I thought was a bug hidden in the semicomplex web app that I'm making, but I have pared it down to the simplest code possible, and it is still replicable in Firefox, Chrome, and Safari, unpredictably but more than 1/2 of the time.

http://jsfiddle.net/cDpV9/7/

var v = $("<video id='v' src='http://ia600401.us.archive.org/18/items/ForrestPlaysTaik/forresto-plays-taik-piano-360.webm' autobuffer='auto' preload autoplay controls></video>");
$("#player").append(v);

1. Add a video element.
2. Video starts to load and play.
3. Video audio sounds like it is doubled.
4. Pause the visible video, and one audio track continues.
5. Delete the video element; the ghost audio keeps playing.
6. Delete the frame, and the ghost audio stops (though once in Firefox it continued to play after closing the window, and didn't stop until quitting Firefox).

Here is a screen capture to maybe show that I'm not completely crazy: http://www.youtube.com/watch?v=hLYrakKagRY

It doesn't seem to happen when making the element with .html() instead of .append(), so that's my only clue: http://jsfiddle.net/cDpV9/6/

$("#player").html("<video id='v' src='http://ia600401.us.archive.org/18/items/ForrestPlaysTaik/forresto-plays-taik-piano-360.webm' autobuffer='auto' preload autoplay controls></video>");

I'm on OS X 10.6.7.

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I think that I have it. Even just creating the JQuery object without adding it to the page causes the ghost player to play: http://jsfiddle.net/cDpV9/8/

var v = $("<video id='v' src='http://ia600401.us.archive.org/18/items/ForrestPlaysTaik/forresto-plays-taik-banjo-360.webm' autobuffer='auto' preload autoplay controls></video>");

For now I can work around this by using .html(). I'll report the issue to JQuery.

Answer 1

Maybe jQuery caches the content of $() before appending it to your player div? So there is another instance of the video tag. It could be an error in jQuery. Have you tried this without Jquery/js?

Answer 2

I would try adding the autoplay attribute after you append the video player. This should then instantiate the play function.

That would be something like this:

var v = $("<video id='v' src='videofile.webm' autobuffer='auto' preload controls></video>");
$("#player").append(v);
v.attr('autoplay','autoplay');

When you create elements in JavaScript i.e. image elements, objects etc, they are loaded instantly and stored in memory as objects. That is why you can preload images before you load a page. It is therefore not a jQuery bug.

Ref: http://www.w3.org/TR/html5/video.html#attr-media-autoplay

When present, the user agent (as described in the algorithm described herein) will automatically begin playback of the media resource as soon as it can do so without stopping.