[whatwg] Html 5 video element's poster attribute

Shiv Kumar skumar at exposureroom.com
Sun Sep 19 19:57:20 PDT 2010

I'll try and respond to everyone that's replied...

First I do want to make clear that it's not about being able to do things via script, but rather declaratively via attributes to the extent possible. At least that's the way I feel Html should be. That is, to the extent possible, Html should be self sufficient, without requiring JavaScript to get the job done. I mean that is the direction we're trying to take Html 5 in isn't it? All of the things people have been doing over the years using JavaScript are finding their way into the Html spec (such as date, validations, required etc.).

I'm glad to see that people do see the need to change (or specify in more detail) the behavior of the poster at least insofar as it disappearing before the video is played. As far as I know, every major browser (IE 9 beta, Firefox, Safari, Chrome and Opera) do this. So I wouldn't categorize this as a bug but rather that the spec needs to be specific about this case.

As regards having control over the poster's visibility using attributes/script, the use case I can think of is, that currently there is no way to make it visible if one wanted to. Typically, we show the poster after the video has ended because it implies to our users that they can play the video again if they want to. And the poster *is* the identifier of the video and not a usually black frame and content producers frequently want us to show the poster after the video has ended.

Seeing that there is no way to show it again (after it has disappeared) I think that there should be a way to make it visible. Website developers are then free to make the choice for themselves. As it stands now, one is forced to overlay an image over the video tag and not have any use for the poster attribute if one wants to turn on the poster.

Yes, I know one can assign/un-assign the poster attribute. But really is that how we see functionality of a new spec is to be implemented? And even this solution will not make the poster visible when required (or when desired).


-----Original Message-----
From: simetrical at gmail.com [mailto:simetrical at gmail.com] On Behalf Of Aryeh Gregor
Sent: Sunday, September 19, 2010 8:50 PM
To: Shiv Kumar
Subject: Re: [whatwg] Html 5 video element's poster attribute

On Sun, Sep 19, 2010 at 4:53 PM, Shiv Kumar <skumar at exposureroom.com> wrote:
> The poster frame should remain visible until the video is played.

I agree with Silvia, this should be required by the spec.  The
alternative is clearly wrong.  Someone should also file a bug with
WebKit to ask them to change.  If WebKit agrees to change, then I
don't think that changing the spec should be controversial.

> The poster should not show while the player is seeking (some browser
> implementation do show the poster while seeking, resulting a flashes)

This sounds like a browser bug.  You should report it to the implementer.

> The poster should show again after the video has ended.

I'm ambivalent about this.  I could go either way.  It should be
standardized one way or the other, though, and currently it's
standardized as not showing (everyone does that, right?), so I'm okay
with keeping it there.

> The visibility of the poster should be scriptable and/or controllable using
> an attribute. Meaning that one should be able to turn on/off the poster
> (without changing the poster attrbute’s value)

I don't see why this is necessary.  You can just do

video.dataset.poster = video.poster;

to remove it, and

video.poster = video.dataset.poster;

to restore, if you like.  (In browsers that implement dataset, which
is apparently only WebKit so far.  But you can easily store the
original value someplace else, although not quite as elegantly.)

More information about the whatwg mailing list