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Re: Firing media events early for throttled downloads

From: Ian Hickson <ian@hixie.ch>
Date: Thu, 30 Apr 2009 00:23:51 +0000 (UTC)
To: Robert O'Callahan <robert@ocallahan.org>
Cc: public-html <public-html@w3.org>
Message-ID: <Pine.LNX.4.62.0904300023380.10370@hixie.dreamhostps.com>
On Thu, 2 Apr 2009, Robert O'Callahan wrote:
> Suppose a page waits for the "canplaythrough" or "load" events to fire 
> on an "autobuffer" media element before it starts playing the media. 
> Then suppose that a user-agent has a media data cache that's smaller 
> than the size of the media resource, so after loading some amount of the 
> data the user-agent decides to pause the download because the cache is 
> full. Unfortunately, the page will never start playing the media.
> Authors can work around this by starting playback on receiving the 
> "stalled" event. (I'm assuming the the user agent is able to free up 
> cache space for played media data, so it will be able to resume the 
> download and eventually play the entire resource.) But that event could 
> fire in other situations, say due to temporary network stalls, when the 
> page would not need to start playback. It's also a trap for authors; in 
> testing they might never notice that the "stalled" handler is needed.
> Should the spec allow the user-agent to set the media element ready 
> state to HAVE_ENOUGH_DATA, and to fire the "load" event, if it pauses 
> the download due to local resource constraints that may persist 
> indefinitely?

The 'suspend' event, already specified, is intended for this case.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Thursday, 30 April 2009 00:24:29 UTC

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