[whatwg] Html 5 video element's poster attribute

Chris Pearce chris at pearce.org.nz
Mon Sep 20 21:14:19 PDT 2010

  On 21/09/2010 2:37 p.m., Robert O'Callahan wrote:
> On Mon, Sep 20, 2010 at 10:31 PM, Shiv Kumar <skumar at exposureroom.com 
> <mailto:skumar at exposureroom.com>> wrote:
>      The only thing that remains then is if web developers would like
>     control over the poster, such as to show the poster after the
>     video has ended, then there should be a way to do that. For this
>     we need a method to show the poster once again. Current there is
>     no way to get the poster to show again and the load() method is
>     not the answer, nor is resetting. A simple method that does not
>     impact anything else will do the trick.
> I am trying to understand why load() is not an adequate answer.

One caveat: if you use load() to reset the poster image, you'll trigger 
all the events and state changes, and reset the volume, currentTime, 
playbackRate and so on.

On 21/09/2010 2:31 p.m., Shiv Kumar wrote:
> Now if you want to change the source of the video in mid play to a 
> better or lower quality version of the same video then you have to go 
> through a few more hoops (and the load() method is used at this time – 
> but you don’t want the poster to show either).

Wouldn't it be better to load() the new resource in a separate video 
element, and then swap it into the DOM when it's completed loading and 
seeked to your change over point? Wouldn't that be more seemless?

On 21/09/2010 3:36 p.m., Shiv Kumar wrote:
> Here are some contradictory cases that may serve as use cases to 
> justify the need to have a spate method:
> 1. Some websites, don’t bother showing the poster after the video ends 
> while providing the content producer to override.
> 2. Some websites (and mobile devices) default to showing the poster 
> after the video ends and allowing the content producer to override
> 3. Some websites show the poster whenever the video is paused.
> Given the above cases, having a method the specifically controls the 
> visibility of the poster (alone) will allow all of the above cases to 
> be implemented.

If we wanted to go down this path, I think a settable attribute 
'postervisible' would be the way to go. Setting to true would show the 
poster, and the browser would automatically hide the poster the next 
time it updates the video frame (the next time playback starts and after 
a seek completes). The attribute would also be readable from script. 
We'd probably want to dispatch a 'posterhidden' event when the poster is 
hidden as well, and maybe a 'postershown'  event as well.

But wouldn't anyone who wanted this level of control have their own 
custom video controls anyway, so that they could ensure they looked the 
same across all browsers? In which case they'd have their own custom 
poster image implementation anyway?

Chris P.
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